Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001
SCIENTIFIC PAPERS ON
WORKSHOP OF THE COMPLUTENSE-
“CÁTEDRA COMPLUTENSE” PROJECT
Principal editor: Redondo, C.
WORKSHOP OF THE COMPLUTENSE-
“CÁTEDRA COMPLUTENSE” PROJECT
2 ND EDITION
Juan D Centeno
Almudena de la Losa
M Ángel de Pablo
M Teresa López Bahut
M Eugenia Moya-Palomares
Olga San Juan
Printed by Department of Geodynamics. Faculty of Geological Sciences. Complutense
University (Spain). Madrid, 2001
“The University Complutense of Madrid (UCM)”.
Centeno, J. D. ……………………………………………………………………………4
“The Faculty of Geological Science”.
Centeno, J. D. …………………………………………………………………………5
“Spain: general features of the country (Geology and Hydrogeology)”.
Villarroya, F. ……………………………………………………………………………6
“Hidrogeologic and environmental issues of the Llanura Manchega
and Campo de Montiel aquifers”.
Montero González, E. .............................................................................................…….14
“Hidrogeologic and environmental issues of Aragón Region”.
Sánchez, J.A., Pérez, A., Roc, A.C. and Rubio, J.C. ……………………………………39
“Fieldtrip to the upper Lozoya valley and Peñalara hanging glacier cirque”.
Centeno, J.D. and Moya-Palomares, M.E. ..…………………………………………67
“Evaluation of the runoff erosion in the drainage basin of the Puente
Alta Reservoir (Segovia)”.
Bodoque, J.M ..............................................................................................................…73
“Terrain analysis in coastal erosion and fluvial morphometry”.
Garrote, J. ................................................................................................................….78
“Naturally occurring arsenic in groundwaters of the Madrid Tertiary
Detrital Aquifer (Spain)”.
Hernández, M.E. ...........................................................................................................82
“The origin and significance of phosphorous in a periurban, alluvial aquifer”.
Himi, Y. and Alvarez-Cobelas, M. ................................................................................90
“Hydrogeological and hydrochemical study of Lozoya River High
Catchment (Madrid, Spain)”.
López, M.T., De la Losa, A. and Redondo, C. ............................................................….95
“Preliminary sedimentological and geomorphological evolution in
a part of the Guadiana Basin between Mérida and Badajoz (Spain)”.
Moya-Palomares, M.E., Centeno, J.D. and Azevedo, T.M. ........................................102
“Present and past floods in the Guadiana River Basin: hydro- and
Ortega, J.A. and Garzón, G. ….…………………………………………………….107
“Historical floods analysis between the Atlantic and the Mediterranean
watersheds in Central-South Spain”.
Potenciano, A. and Garzón, G. ……………………………………………………112
“Microbiological study of the incrustations and corrosions in
Senderos, A., Villarroya, F. and De Castro, F. ............................................................116
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001
Since the beginning of the nineties our universities (University Complutense of Madrid
and Charles University in Prague) collaborate by mean of the project "Cátedra Complutense".
Since then, two fields of the project had been accomplished: an humanist part in order to
improve the Spanish culture and language in the Czech Republic and a scientific side related
mainly with Hydrogeology. In such manner some people (faculty and studies) had the
opportunity to work in Prague and Madrid respectively extending their professional knowledge
and meeting scientists and people.
Last year, the 1 st Workshop of the project devoted to "Sustainable development of water
resources in fractured rocks: environment issues", was held in the Czech Republic, and made
possible to organize this second Workshop of the "Cátedra Complutense".
Our meeting on "Groundwater and Landscape Sustainable Management" will be
performed between 21 st of September to 1 st October 2001. We devote our field trips to see and
discuss specials problems related with water and landscape management in La Mancha, the
Ebro basin, the Pyrenees and the Guadarrama range.
We plan to start with a lectures and discussions day, devoted both to give the
participants basic information for the following days field trip and to discuss the related
research of the Department of Geodinamic.
In La Mancha, where Cervantes imagined Don Quijote heroic deeds we will visit the
overexploited aquifer of La Mancha and work on its big problems like overexploitation, and
critical environmental problems like contamination, rivers and cracks completely dry and
spontaneous combustion of peat who were the bed of the Guadiana river, and the interland
wetland of Natural Park of Ruidera lakes, where wetland conservancy and agricultural
development are the main conflict to solve.
In Aragón will have the opportunity to visit the most important aquifer in Ebro basin:
the Alfamén-Cariñeña Area. In Pyrenees mountains we have the opportunity to visit some
thermal springs and spaas.
In Guadarrama range we will visit the mountain wetland of Peñalara glacier cirque, a
good example of integral conservation of geomorphological, hidrogeological and ecological
The organizers want to show their acknowledge to the University Complutense, that
founds this project specially to the Vice-Rector of International Affaires for this invaluable
help and energy and to the Faculty of Geology and the Department of Geodinamic for their
We want to welcome the Czech and Spanish participants to this Workshop. Moreover,
we hope it will be successful in the scientific and human aspects. For sure, the discussion of
ideas in such a large body of faculty and students will allow a productive exchange of
experiences on the field of both environment and hydrogeology.
On behalf of all my colleagues and ph-students and postgraduates students who helped
us in order to prepare this Workshop we would like to welcome all participants to Madrid and
Dr. Fermín Villarroya
Head of Department of Geodynamics
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 4
THE UNIVERSITY COMPLUTENSE OF MADRID (UCM)
The University Complutense of Madrid recently celebrated its seven hundred
anniversary. The 20 th May 1293, the Castilian king Sancho IV ordered its foundation in Alcalá
de Henares the former Roman town of COMPLUTUM - in a time of Muslin-Christians war the
roman name was chosen by the new University.
Such foundation date makes the Complutense the third Spanish University, after
Salamanca and Valladolid Universities. But a second foundation should be cited. In 1495
Cisneros (later Cardinal Cisneros) is designated Archbishop of Toledo and becomes the real
founder of our University in a difficult process that last until 1513 when himself declare to be
the “School and University of Alcalá founder”. This double foundation seems to be in the
destiny of our University for in October 1836 the University of Alcalá de Henares is closed to
create in Madrid the Central University, forgetting the term Complutense until the 1970’s when
it is recovered and the new University of Alcalá de Henares is created.
The first production of the University Complutense is the opera magnum of the
Cardinal, the Bible Poliglota (multilingual) that made the University a leading publishing centre
in western Europe. Since then, many Spanish humanist and scientist have studied or worked in
the Complutense making it a basic centre for Spanish development and culture. Antonio de
Nebrija, San Juan de la Cruz, Pedro Calderón de la Barca or Francisco de Quevedo can be cited
among de classics. But also Manuel Bartolomé de Cossío, Santiago Ramón y Cajal, Gregorio
Marañón, José Ortega y Gasset or Severo Ochoa are between the Complutense outstanding
Nowadays the University Complutense is the biggest University of Spain and one of the
biggest of Europe. Around 90.000 students and 5.000 faculty in 25 centres, 70 degrees and
many postgraduates study plans make it an pivot teaching institution. But also it is a main
research establishment, leading the Spanish science and humanity in many fields and devoting
to fringe science more space and effort than any other Spanish University.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 5
THE FACULTY OF GEOLOGICAL SCIENCE
The Faculty of Geological Science history goes back to 1944 when the Faculty of
Science establish four sections (Mathematics, Physics, Chemistry and Natural Science) and a
Doctorate on Geological Science. In 1964 the section of Natural Science is divided in two
sections of Biology and Geology and, finally, in 1975 the Faculty of Geological Science is
In the meantime, the degree “Licence in Geological Science” was former regulated in
1953, following official changes in 1962, 1969, 1975 and 1994 (changing the last one the
official name to “Licence in Geology”). This degree on Geology can be obtained also in the
universities Autónoma of Barcelona, Barcelona, Bilbao, Granada, Huelva, Oviedo, Salamanca y
Zaragoza. In addition, since 2000 a title of Geology Engineer can be followed in our Faculty
and the universities of Alicante, Barcelona and Polytechnic of Madrid.
The Faculty of Geological Science is organised into five departments:
• Crystallography and Mineralogy
• Petrology and Geochemistry
There are around 1200 students, 112 faculty staff and 70 technical and auxiliary staff.
Moreover, some 60 postgraduate students follow some of the two PhD Programs (Geology and
Geodinamics) or the interunivesities PhD Program on Palaeontology.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 6-12
SPAIN: GENERAL FEATURES OF THE COUNTRY
(GEOLOGY AND HYDROGEOLOGY)
Department of Geodynamics. Faculty of Geological Sciences. Complutense University. 28040 Madrid (Spain)
By virtue of its relief (average altitude of 600 m and one-sixth of its area above 1.000
m), the variety of its climate, the length of its coastline (more than 7.000 km with many
beaches) and his historical and cultural heritage, Spain is a microcontinent where virtually all
types of crops can be found. All these factors, together with an intermediate level of economic
development and an acceptable network of infrastructures and amenities, have turned the
country into a prime destination for tourists. Tourism represents close the 11% of the Gross
Domestic product, accounts for annual revenues exceeding more than 26.000 millions of euros
and generates more than one million jobs. Earnings from tourism cover 21,5% of all imports. In
1997, Spain received 64,5 million visitors. Of these, 43,4 million were real tourists, who
consumed tourist service on Spanish soil. The remaining 21,1 million were on day trips, cross
border visitors, or in transit. (MEH and MIMAN, 1999). The other hand, management of
twelve National Parks and other statutorily protected areas has made it possible for conservation
of places of special environmental importance to be combined with an annual influx of visitors
numbering over nine millions, (we expect visit some of them during field trips). Apart from
National Parks, the Autonomous regions have brought in different legal formulae for
environmental protection purposes; in total, there are 580 protected areas in Spain , extended
over 2.700.000 hectares.
The main figures of Spain are:
• 40 million inhabitants
• 504.745 km 2
• 174.745 km 2 permeable outcrops
• recharge 100 mm/y (20.000Mm 3 /y)
• 442 aquifer systems
• surface runoff 95.000 Mm 3 /y
• groundwater extraction 6100 Mm 3 /y
18% water supply
6% industrial use
76% agricultural use (irrigation)
Spain is a partially industrialized country with a modest economy in comparison with
some other members of the European Union. It is the most arid country in Europe. The
economy have relied heavily on irrigated agriculture, which is a major consumer of fresh-water
resources but now is not a major contributor to the Gross National Product of Spain. This
situation is quite different from that in most other countries of the European Union.
Water has long been recognized as a valuable resource and a critical factor in public
health and welfare. For several decades, water has also become recognized as being essential for
the functioning of most ecosystems. The role of groundwater in the hydrological cycle has been
known for more than three centuries. Nevertheless, the potential role of groundwater is often
downplayed in the water policy of many countries. Water planners often prefer surface-water
solutions even at the expense of conjunctive use of surface water and groundwater, which is
either not considered or misapplied. In the early 1970s, the attitude of some hydraulic engineers
to draw a sharp distinction between groundwater and surface water, and disregarding the
former, was characterized as "hydroschizophrenia" by Nace (in Llamas, 1985). Llamas, studied
this syndrome and concluded that one major cause of hydroschizophrenia in Spain was the
failure during the previous century to cope with the increasing water demand of the city of
Madrid by means of groundwater using infiltration galleries and water wells. At that time it was
decided to import surface water from the nearby mountain ranges with the aid of dams and
aqueducts. The centralized nature of the Spanish Administration until the drafting of a new
Constitution in 1978, the unhealthy competition between two rival ministries in charge of
surface and groundwater, and the promulgation of hydroschizophrenia through most civil
engineering schools and research institutions in Spain have helped to spread the malaise across
the entire country, thus adversely affecting Spain's national water policy. The private sector did
develop groundwater when surface water from public projects was not available, but often
without sufficient knowledge or safeguards to sustain this precious resource. There have been
some exceptions, such as the successful management schemes of water in Barcelona, but even
in those cases the public water administration has often been more of a hindrance than help in
the initiation and maintenance of sound groundwater management practices.
OUTLINE OF SPAIN'S GEOLOGY, HYDROGEOLOGY AND GROUNDWATER USE
Spain is located in the southwestern corner of Europe, separated from Africa by the
western Mediterranean Sea. Spain comprises the larger part of the Iberian Peninsula (the rest is
Portugal) and includes (a) two main archipelagoes, the Balearic Islands in the Mediterranean
Sea and the Canary Islands in the Atlantic Ocean, which face the African continent (b) two
small peninsulas in northern Africa, Ceuta and Melilla; and (c) several small islands. (Locations
are shown in Figure l).
Since the democratic system was restored by the 1978 Constitution, Spain has
comprised 17 autonomous communities, plus the enclaves of Ceuta y Melilla in North Africa.
The basement of the Iberian Peninsula is formed by folded and partly metamorphosed
Hercynian-age rocks. These rocks crop out in the northern and northeaster parts of Spain and
form the basement of the central highlands (Mesetas). Thick Mesozoic-age sediments,
predominantly carbonates and marls with evaporites, were deposited around and on the
basement rocks. These formations were covered by early Cenozoic-age sediments that contain a
large proportion of carbonates along the Mediterranean coast (Fig. l). Mountain ranges,
reactivated during the Alpine orogeny, occur at the margins and across the Central highlands,
with intensive folding and thrusting of sediments of pre-Miocene age. Large and deep grabens
were formed, which are filled with a variety of materials, from arkosic sand to playa-lake
evaporitic sediments, mostly unfolded. They constitute a major part of the main river
watersheds and contain some extensive aquifers such as those of the Duero and the Madrid
basins. General descriptions can been found in Custodio et al 1997, and López Geta et al, 2001).
In broad terms, the Iberian Peninsula consists of a western and northwestern hard-rock
domain; a central domain, dominated by clastic, often fine-grained and clay-rich sediments; and
a northern and Mediterranean domain, with extensive thick carbonato formations. Restricted,
but thick and well-developed, Quaternary-age deposits along the major river valleys and the
coastal plains play important roles as aquifers. Gypsum and anhydrite are widespread in the
southeastern part of the Peninsula, where the associated saline waters occur.
The Balearic Islands are part of the carbonato region of the Mediterranean basin, with a
deep sea-occupied trough in between. The Atlantic volcanic archipelago of the Canaries consists
of high and large volcanic formations arising from the deep ocean floor, except the easternmost
islands, which rest near the African continental shelf. Some islands are very high, up to 3700 m
above sea level in Tenerife, from a submarine base more than 3000 m deep. Volcanism started
in the Miocene epoch and comprises several episodes of basic to intermediate eruptions, with
intensive landslides, and with intervening dormancy, during which deep gullies (barrancos)
were incised. Volcanism is still active episodically. The oldest parts of the islands have low
permeability, but young volcanics are often very pervious. A core of low-permeability material
exists that is sometimes exposed but more often buried below recent lava flows that extend
down to the coast. The groundwater body may occur at high altitudes, but most of the
groundwater flows within the cover of young volcanics.
Fig 1.- Spain and main aquifers.
Spain has a diversity of climates due to its position between a temperate European zone
and a subtropical area. It includes some of the most rainy areas of Europe, such as Galicia in the
northeastern part and Grazalema in the southeastern part, with more than 2 m/a; and the most
arid areas, such as Cabo de Gata (Almería) in the southeastern part, with less than 0.2 m/a and
some regions of the Canary Islands, with 0.1 m/a). The coastal plains along the Mediterranean,
the Ebro central basin and the two main archipelagos (except their high mountains) are
semiarid, with a distinct, long dry summer season, during which there is a pronounced soilmoisture
deficit and little aquifer recharge.
Groundwater Resources and Aquifers
Of a total surface area of 504,750 km 2 , according to official data of "Dirección General
de Obras Hidráulicas" (DGOH 1994), 174,745 km 2 are permeable outcrops. Aquifer recharge
along these outcrops is approximately 20 x 10 9 m 3 /a, at a rate of 100 mm/a. This amount has
been estimated by the Water Administration by assigning recharge rates that range from 16-479
mm/a, to the area of each aquifer system. The Water Administration (SGOP 1990) has
identified 442 aquifer systems.
Surface runoff across Spain is officially estimated to be approximately 95 x 10 9 m 3 /a, or
approximately five times larger than groundwater recharge. This questionable and poorly
supported ratio has been in the past and still is today frequently quoted in order to make a case
for the construction of large dams at the expense of utilizing, managing, and protecting
Groundwater Use and some problems
Groundwater is tapped directly at the springs (which often are considered as surface
water) or abstracted by means of wells, some of them deeper than 500 m. The number of wells
is officially estimated at approximately half a million, but in fact more than one million
groundwater uptake points may exist. Following the Water Act of 1985, groundwater became a
public community. Prior to this act, it was the private property of well owners (Water Act of
According to DGOH (1994), groundwater uptake increased from 0.5 x 10 9 m 3 /a in 1900
to the current rate of approximately 6.1 x 10 9 m 3 /a. Approximately 1.1 x 10 9 m 3 /a (18%) is used
as public drinking water for 31% of the nearly 40 million inhabitants of Spain. Approximately
0.4 x 10 9 m 3 /a (6%) supplies the industrial sector. The rest, approximately 4.6 x 10 9 m 3 /a , is
allocated to irrigation; 700,000 ha of land is irrigated solely by groundwater, and approximately
300,000 ha by groundwater and/or surface water. The total irrigated area of Spain is
approximately 3.5 x 10 6 ha. Surface water is used for the irrigation of 2,500,000 ha at a rate of
approximately 20 x 10 9 m 3 /a. In other words, the applied water per hectare in surface-waterirrigated
areas is approximately double that of areas irrigated with groundwater.
Most surface-water irrigation projects were constructed in the second half of this
century and were financed with public funds. In contrast, groundwater development has been
pursued and financed by private farmers and small -or middle-sized towns. This virtually
uncontrolled and unplanned development has led to real or apparent problems of (a) overdraft or
overexploitation, (b) seawater intrusion, and (e) wetland degradation.
Official data (DGOH 1994) suggest that 51 aquifer units from the total 442 are
overexploited, with pumpage exceeding recharge by 0.7 x 10 9 m 3 /a, and 48 units are close to
being overexploited. Some complex and partially effective legal action has been taken in 18
aquifer units with a surface area of 13,000 km 2 . Abstraction rate is 1.1 x 10 9 m 3 /a, which is
assumed to exceed recharge by 0.5 x 10 9 m 3 /a. In some areas in southeastern Spain and the
Canary Islands, groundwater drawdown rates as much as several m/y are not rare, but this is not
necessarily due to an excess of abstraction over recharge. In some cases a dry period in which
recharge is low and/or a long-term transient situation can explain a significant part of such
drawdown rates. The term overexploitation has often been used to imply different meanings
within different contexts (Simmers et al 1993; Villarroya and Adwell, 1998).
Intensive development of coastal aquifers has often produced problems related to
seawater intrusion, although many such problems can be attributed to poor management and
inadequate well location or construction. These -coastal aquifers play, or should play, a key role
in peak, emergency, and drought water supplies for towns as well as a complementary source of
water for irrigation in coastal areas. According to DGOH (1994), of 82 coastal aquifer units, 15
have been seriously invaded by seawater, 27 other units have large areas with intrusion and 6
units have local problems.
According to the Water Act of 1985, wetlands have to be protected and preserved. The
DGOH (1994) study mentions 1533 groundwater-related wetlands of various sizes, with a total
current surface area of 800 km 2 , approximately 65% of the original 1250 km 2 . Some of them,
including several that have international relevance, are being threatened or degraded by
groundwater abstraction, but in other cases the assumed ecological impact of groundwater
abstraction has been used to justify the construction of large dams for other purposes.
Official data on groundwater contamination are scarce and sketchy, even for natural
sources of salinity, which play a significant role in some areas. Aquifer pollution by human
activities may be serious in some areas (Custodio 1992), although fortunately there are large
areas of rural, forest and natural parks in which the risk of pollution is small. Agriculture is a
main contributor through massive use of fertilizers and other agrochemicals for intensive crop
production, mainly along the Mediterranean coast and on the islands. According to DGOH
(1994), the mean rate of nitrogen use in agriculture has increased from 12 kg/ha/a in 1955 to
nearly 60 kg/ha/a in 1988. In parts of some aquifers there are areas in which NO 3 in
groundwater exceeds the 50-mg/L limit for drinking water, in places reaching 200 or even 500
mg/L. Current use of pesticides ranges from 2-12 kg/ha/a, but studies of their impact on
groundwater are scarce. In some areas, intensive raising of livestock causes serious nitrate
problems and reducing conditions in groundwater that increase iron, manganese, and other
A few documented cases exist of groundwater contamination by hydrocarbons, organic
chlorinated solvents, and heavy metals; however, data are scarce. Such cases are not mentioned
in the White Book on Groundwater by the DGOH (1994). New cases are appearing more and
more often, showing that it seems to be a widespread problem. Such industrial contamination
may jeopardize the sustainable use of aquifers as an inexpensive and reliable source of water in
case of drought, emergency, and peak demands in and around urban areas.
MAIN DIFFICULTS WITH SPANISH GROUNDWATER POLICY
Llamas (1997) categorizes the causes of water problems in the Iberian peninsula as
either ethical, aesthetic, or technological. The salient points of his paper in relation to
groundwater are summarized below.
The main reason for the relatively scarce use of groundwater in Spain, and for its poor
management with consequent overexploitation, seawater intrusion, wetland degradation, and
groundwater pollution (several examples of this, will be more in detail show during the field trip
excursions), is the method by which taxpayers' money is allocated to water projects. Most dams
and canals (built for irrigation projects, or for water supply to large towns, during this century)
have been designed and paid by the Ministry of Public Works. Only dams built for hydropower
have been financed by the private or semipublic sectors. In Spain, the lobbies of large
constructors and of farmers have been and still are very successful in draining public funds for
large hydraulic works for urban water supply or irrigation. On the other hand, groundwater
development has been financed primarily by private entities, mainly farmers of modest means,
local water suppliers and factories. It is not easy to alter this situation because of the mental
inertia of many engineers involved in water management who think in terms of "hydraulics"
rather than "water resources and the lobbying power of large construction companies.
Another obstacle to the rational use of groundwater is the poor participation of
groundwater users in the management of aquifers. This situation is in contrast to traditional
social participation of surface-water users in its management. A prime example is the wellknown
"Tribunal de las Aguas" (Water Jury) of Valencia that has been in operation for seven
centuries. The 1985 Water Act attempted to create similar participation among groundwater
users, but thus far, corresponding efforts by Water Authorities have been largely unsuccessful,
with a few exceptions.
Most systematic hydrogeological surveys have been conducted by the Geological
Survey of Spain (IGME). The Ministry of Publics Works had only a small team of
hydrogeologists, some of whom were of excellent professional level but held little authority.
Sixteen years after the 1985 Water Act, the number of hydrogeologists among officials of the
Water Authorities remains pitifully small. This lack of expertise with authority within the
Spanish Water Administration is a major reason for the underexploitation, the overexplotation,
and the general mismanagement of groundwater resources in Spain. This is also why legal and
administrative control of groundwater quality is so weak, despite improved legislation
concerning water supply. Groundwater pollution is seldom mentioned, and when it is referred to
the objective usually is to justify large surface-water or desalination projects to supply potable
water to urban areas formerly supplied with the unpolluted groundwater.
As it happens, with a few exceptions groundwater has never been properly investigated
or controlled by Spain's Water Authorities. Instead, hydraulic engineers working for the Water
Authorities are often responsible for man "hydromyths" regarding groundwater that have been
circulating through Spain in recent years. Among these hydromyths, perhaps the most pervasive
is that "the fate of every water well is to become dry or brackish." The logical conclusion of this
wrong philosophy has been the continuation of construction of large dams and canals.
THE BRAND NEW SPANISH NATIONAL HYDROLOGIC PLAN
After more than twenty years (the first documentation involved is dated in 1980), a
brand new and polemic Plan about water has been launched in Spain. Official issue was the 6 th
of July (BOE nº 161, 2001). The Plan want to correct the more dry areas of the peninsula by
mean of one big divertion of water from the Ebro river (the most important river of Spain). But
the problem is that in the mouth of the river there is the Ebro Delta, a very important
ecosystem. The Plan envisages to transfer 1050 Mm 3 of water to de shout basins of the
Mediterranean facade of Spain:
Transferences to be accomplished from the Ebro river:
• 190 Mm 3 to Catalonia
• 315 Mm 3 to Júcar basin
• 450 Mm 3 to Segura basin
• 95 Mm 3 to South (Almería)
1050 Mm 3
Many people from the universities and from other institutions have made efforts against
the Plan because seem to be expensive, antiecologic, hydrosquizofrenic, and deterministic
approach. We expect that finally (fortunately the big (faraonic) construction meaning years
under construction) only one fraction of the dams, channels, and so on, envisaged, will be built.
BOLETÏN OFICIAL DEL ESTADO (BOE) (2001) "Ley 10/2001 , de 5 de julio, del Plan
Hidrológico Nacional”. Boe nº 161 pp 24228-24250
CUSTODIO, E. (1992) “Groundwater pollution in Spain: general aspects” J, Inst Water
Environ. Management 6 (4): 452-458
CUSTODIO, E.; LLAMAS, M.R. and VILLARROYA, F. (1997) "The role of the Spanish
Committee of the International Association of Hydrogeologists in the management and
protection of Spain´s groundwater resources" Hydrogeology Journal vol, 6 , pp-15-23.
CUSTODIO, E. (1993) Is groundwater overexploitation a new hydrogeological concept?
Groundwater Goengineering, IGEA, Assoc Mineraria Subalpina, Torino, vol 2 pp 5-14
DIRECCIÓN GENERAL DE OBRAS HIDRÁULICAS (DGOH) (1994) “ White book on
groundwater in Spain” Serie Monografías. Servicio de Publicaciones del Ministerio de Obras
Públicas, Transportes y Medio Ambiente. Madrid, 135 pp.
LÓPEZ GETA, J.A.; FORNÉS, J.Mª Y VILLARROYA, F (2001) "Aguas subterráneas. El
inestimable recurso del subsuelo" Edit IGME y Fundación Marcelino Botín 100 pp ( in press)
LLAMAS, M.R. (1985) “Spanish water resources policy: the illogical influence of certain
physical and administrative factors” Mem 18 th Int Congr, Int Association of Hydrogeologists
LLAMAS, M.R.(1997) “Transboundary relations in the Iberian Peninsula, an area with limited
water resources” In: Ghleditsch NP (ed) Conflict and environment. Kluwer, Amsterdam, pp
M.E.H and MIMAN (1999) "Spain: a sustainable tourism" Ministry of Economic and Tax and
Ministry of Environment. Madrid, 97 pp
SERVICIO GEOLOGICO DEL MINISTERIO DE OBRAS PÚBLICAS (SGOP) (1990)
"Unidades hidrogeológicas de la España Peninsular e Islas Baleares: sintesis de sus
características y mapa a escala 1/1000000 (Groundwater units of Peninsular Spain and Balearic
islands)”. Servicio Geológico. Madrid. Informaciones y Estudios, v 52, 32 pp.
VILLARROYA, F. and ADWELL, C.R.. (1998) "Sustainable development and groundwater
resources exploitation" Environmental Geology 34 (213) May 1998 pp 111-115.
SIMMERS I.; VILLARROYA F. and REBOLLO, L.F. (1993) "Aquifer overexploitation"
Selected Papers Hydrogeology v, 3 1; 392 pp
1.- Llanura Manchega and Campo de Montiel
2.- Aragón Region
3.- Lozoya Valley and Peñalara (Madrid)
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 14-38
HYDROGEOLOGIC AND ENVIRONMENTAL ISSUES OF THE
LLANURA MANCHEGA AND CAMPO DE MONTIEL AQUIFERS
Department of Geodynamics. Faculty of Geological Sciences. Complutense University. 28040 Madrid (Spain)
The Mancha region, where the Llanura Manchega (Manchega Plain) and the Campo de
Montiel (Field of Montiel) aquifers are sited, has a dry mediterranean climate, with special
geologic and hydrogeologic characteristics, which always have conditioned the access to the
water of the population; this have had a cultural and economic influence.
The aridity that characterizes the area contrast to the big number of existent wetlands:
meandering rivers, flood plains, stepper lakes, carbonate, chloride and sulphate springs,
sometimes with high concentrations. This group of wetlands form the “Mancha Húmeda” (Wet
Mancha) standing out two among them due to its beauty and importance as ecosystems: Las
Tablas de Daimiel and Las Lagunas de Ruidera.
Agriculture, which has been the main source of richness in La Mancha, has broken the
equilibrium which allowed the diversity and stability in the exploitation of hydraulic resources
until the sixties decade. The develop of irrigation from groundwater in the region led to an
exclusive use of the water in the agriculture sector, which has cause among other effects, the
destruction of many wetlands and a serious threat over other (Rueda, 1992).
1.- GENERAL FEATURES OF THE AREA
At the high catchment of the Guadiana River to El Vicario reservoir is sited the Llanura
Manchega (figure 1). It is a natural region with 16,130 km 2 belonging to the Meridian Castilian
Plateau, sited among the Toledo Mountains, the Iberian Range, the Campo de Montiel and the
Albacete Plain (Llanos de Albacete) (Servicio Geológico, 1988).
The hydrographic boundaries of the catchment are the watershed of the rivers Tajo at
north, Guadalquivir at south and Júcar at east. The most important rivers of this drainage pattern
are: Guadiana, Azuer, Gigüela, Záncara, Córcoles and Bañuelo.
The gentle slope of the rivers and the geologic and rainfall characteristics of the region
give rise to extensive wetlands, being the most important Las Tablas de Daimiel due to its
ecological importance (figure 2).
The area belongs to a temperate climate, dry Mediterranean: mean long-term annual
precipitation is 450 mm with a great seasonal irregularity; mean long-term temperature is 15ºC,
with maximum of about 46ºC and minimum of –19ºC. The mean long-term potential
evapotranspiration is 850 mm/year. These climatic characteristics determine very limited water
resources in the catchment, of about 450 Mm 3 /year. The most singular feature of the region is
the existence of the big underground reservoir of la Llanura Manchega (aquifer 23 or
Hydrologic Unit 04.04), which covers an area of about 5,500 km 2 (figure 2).
Recharge is due to rainfall infiltration, leaking of the rivers (Guadiana, Azuer y
Córcoles) and groundwater from adjacent aquifers (Campo de Montiel). Discharge, in natural
regime takes place through the Ojos del Guadiana (Guadiana Eyes) and close areas (Tablas de
Due to these peculiarities, the Mancha region is one of the better examples in Spain of
surface and groundwater relationship, representing groundwater the main resources, more than
70% from the total. The main use of the water is for irrigation being less important industrial
and human supplies.
The water balance of the aquifer shows a budget deficit between inputs and outputs,
which can be understood because of the aquifer empting, which is, estimated around 4,000
Mm 3 .
This empting, due to a heavy pumping of groundwater, produces a drawdown, which
affect to the non-renewable reserves of the aquifer, what put the agriculture development at risk
in the area (this is the first regional source of richness) and, consequently the next links of the
economical chain (Esnaola, et al., 1995).
The consequences of the aquifer overexploitation have influenced the original
hydrogeologic conditions. Regional groundwater level has fallen and natural discharge areas
have disappeared; this is the case of the Tablas de Daimiel and the Guadiana Eyes (dry since
2.- GEOLOGIC, GEOMORPHOLOGIC AND TECTONIC SETTING
The Llanura Manchega (figure 2) belongs to a morphostructural depression that, with an
ENE-WSW direction, is located in the meridian boundary of the South Plateau. It consists of a
base formed by shales, quartzites, sandstones, conglomerates, clays and gypsum on west area
and limestones, dolomites, marls and sands on centre and east ones (Palaeozoic and Mesozoic).
Over these materials exists a modern continental formation (Miocene) made up of
conglomerates, sands, clays, marls and limestones partially covered by Plioquaternary and
Quaternary detrital materials (figure 3) (Servicio Geológico, 1988). Towards the western of the
Llanura Manchega, at the Campo de Calatrava, remains of volcanic emissions from the upper
Miocene to the lower Pleistocene are frequent. The first lava and volcanic cones have a basicultrabasic
character while the last ones are alkaline and ultrapotasic.
The Palaeozoic forms the base of the sedimentary series and close the western boundary
of La Mancha. It is constituted by lower Ordovician shales and quartzites affected by hercinic
The Triassic is discordant over the Palaeozoic series. Breccias, sandstones, limonites,
clays and some carbonate levels constitute the Triassic. It is the impervious base of the deepest
The Jurassic is sited over the Triassic; it has a calcodolomitc and marly composition,
some of whose levels (Lower and Upper Jurassic) form the deepest aquifers of the area.
The Cretacic is less represented in the area although the most completed series are sited
at the eastern part. It has a detrital composition on the base and a calcareous composition at the
top. The calcareous upper Cretacic is a part of the deep aquifer.
Tertiary and Quaternary materials fill the morphostructural depression. The Tertiary is
discordant with the Mesozoic deposits and is thinner towards the eastern part of the aquifer. It
has a progressive continental makeup with detrital materials at the bottom and a Miocene which
final stretch is composed by sandy limestones that forms the shallow aquifer.
The Plioquaternary has a detrital composition (glacis) and takes part of the shallow
The Quaternary is discordant with many formations in La Mancha. Its litology is varied and it
depends on its origin. It can be distinguished river terraces, alluvial fans and eolian deposits.
The phisiografic and structural unit of the Llanura Manchega takes part of the Iberian
Peninsula foreland area belonging to the Bético-Rifense orogen. It is a depressed area with
heights among 600 and 800 m. The surface and groundwater behaviour shows an asymmetry of
the unit due to a tectonic tilt mainly towards the NW and to a lesser degree to the WSW. Inside
this neotectonic environment of flexural type, the Llanura Manchega depression extends
towards the East towards the Llanos de Albacete unit, and it is surrounded by unites with similar
orientations but with a positive character: Campo de Montiel, Montes de Toledo, Mesa de
Ocaña-Altomira y Campo de Calatrava (Rincón et al., 1996).
Tectonics features constitute the northern and southern boundaries of the unit with
ENE-WSW/E-W orientations while the eastern and western limits are related to SE-NW dextral
strike-slip faults. There is a third fracture type towards NNE-SSW. This fracture network has
conditioned the spatial distribution of rivers and streams and the carbonation-karstification
processes of the carbonate units.
3.- GENERAL HYDROGEOLOGY OF THE AQUIFER
In the Llanura Manchega aquifer, there are two hydrogeologic units, among which there
is a detrital unit (Lower Miocene), with an impervious character, which acts as an aquitard
(Servicio Geológico, 1988).
Upper hydrogeologic unit
The shallow aquifer spreads almost all the plain. Limestones and marl limestones
(Upper Miocene) and detrital material (Plioquaternary and Quaternary) constitute the aquifer,
forming a heterogeneous group with a medium thickness of about 35 m and maximum deeps of
about 200 m.
The Pliocene and Quaternary levels have transmissivities among 0 and 500 m 2 /day and
storages capacities among 10 -1 and 10 -2 . At the calcareous levels, the transmisivities vary among
50 and 20,000 m 2 /day and storage capacities among 10 -1 y 10 -2 .
Lower hydrogeologic unit
The deep aquifer spreads on the eastern sector of the plain. It corresponds to limestones
and dolomites Mesozoic formations that constitute the geologic extension of the Campo de
Montiel and Sierra de Altomira aquifers, which with they have a water connection.
There are three different aquifers (Upper Cretacic limestones, Medium Jurassic
limestones and Lower Jurassic dolomites), folded and separated between them by less pervious
layers, which thickness increase towards eastern. The transmissivity of this unit varies among
200 and 6,000 m 2 /day, and its storage capacity is about 4.10 -3 .
System hydrogeologic behaviour
The upper, is a water-table aquifer with parallel flux directions from east to west, in
spite of some areas present NE to SW (Gigüela-Záncara) and SE to NW (south of Manzanares)
directions. The big pumping cones produce local variations as well.
The recharge of this hydrogeologic unit is produced by: rainfall infiltration over the
Llanura Manchega outcrops; stream water infiltration from close systems (Córcoles, Alto
Guadiana, Azuer, Záncara and Gigüela); irrigation excess infiltration; urban spillage infiltration;
and lateral and deep flows (through the basal Miocene) from the Sierra de Altomira and Campo
de Montiel aquifers.
The discharge of this unit is produced by: pumping extractions, mainly for irrigation
uses but for human supply and industrial uses too; Ojos del Guadiana and Tablas de Daimiel
drainage; and direct evapotranspiration from the aquifer on the western area, where the water
table is near to the topographic surface.
The lower hydrogeologic unit is confined or semiconfined. Its recharge is produced by
the rainfall infiltration on the outcrops of Sierra de Altomira and Campo de Montiel aquifers. Its
discharge is done by the pumping wells that exploit the aquifer and through the drainage from
the Miocene aquitard to the upper aquifer.
An intensive exploitation of the western aquifer for irrigation purposes has been carried
out over the last decades, increasing from 30,000 to 125,000 ha the irrigated land from
groundwater, and from 200 Mm 3 /year to 600 Mm 3 /year (more than twice the recharge in a
medium year) between 1974 and 1987. This exploitation gave rise a progressive decline in the
water levels in the wells, which have gone down as far as 30-35 m in some points; the emptying
volume in the aquifer since 1974 is estimated around 4,000 Mm 3 . It has produced the
disappearance of the emergences of the River Guadiana from the Ojos del Guadiana sources to
Las Tablas since 1983 and the change of Las Tablas into a recharge pond for the surface waters
of the River Gigüela instead of being a discharge zone of the Llanura Manchega aquifer.
Figure 4 present the evolution of the higher limit of the saturated zone from 1989 to
1994, where is appreciate a general drawdown, which rise 35 m in some areas. As regards the
general flow in the aquifer, in the first date it keeps the original circulation sense, flowing to Los
Ojos del Guadiana and Las Tablas de Daimiel. In 1984 there is a depression towards the north
of Manzanares, the groundwater flow is inverted and the piezometric head keep flat and gentle,
which means a flow diminishment to the outlets. In 1987, the situation is similar, with a
growing E-W of the cone. The situation in 1994 makes worse, with two cones more, one of tem
close to La Tablas, where the drawdown are about 15 m and a change of the flow direction to
In February 1987, the aquifer was officially declared overexploited according to the
1985 Spanish Water Law. It implied the banning to carry out new extractions in the aquifer. In
December 1994 was published the definitive declaration.
4.- EXCURSION SITES
OJOS DEL GUADIANA (GUADIANA EYES) (excursion site 1)
The Ojos del Guadiana springs rose in Arenas de San Juan years ago. This point was the
natural water outlet of the Llanura Manchega aquifer (figure 2).
The springs became dry at the end of the seventies and its wide extension was reduced
over the years towards the west area, nearer to Las Tablas de Daimiel.
The enigmatic Guadiana disappearance and reappearance during its flowing through the
Llanura de San Juan is well explained today. The river infiltrated in the Llanura Manchega
downstream the Peñarroya reservoir; there, its waters were mixed up with the aquifer waters
and, 40 km downstream, rose through the Ojos del Guadiana.
The exploitation of the aquifer became intensive at the end of the sixties when pumps
allowed the transformation of unirrigated into irrigation crops. At the end of the seventies the
number of wells have increased so much that the extracted water was much higher than the
recharge one. The exhaustion of some wells increased its number and deep.
A large drought (more than five years) became worse the situation.
The Ojos del Guadiana is one of the natural indicators of the water table in the aquifer
and its worrying drawdown, which affect specially to Las Tablas de Daimiel.
WATER INTERPRETATION CENTRE IN DAIMIEL (excursion site 2)
This museum collect the main natural, social, economic and historic features related to
the water in La Mancha.
It is very interesting the Llanura Manchega aquifer and its relationship with Las Tablas
de Daimiel section.
Models, maps, aerial photographs, satellite images, exhibition panels, dioramas,
aquariums, audiovisuals, etc. show the information.
NATIONAL PARK OF LAS TABLAS DE DAIMIEL (excursion site 3)
Las Tablas de Daimiel (figure 5) is one of the most peculiar ecosystems in the Iberian
Peninsula (Álvarez et al., 1996). This freshwater table is composed of a mixture of shallow,
seasonal waters and deeper, permanent ones. Two decades ago, it arose as a result of the
flooding of the Gigüela and Guadiana rivers together with the upwelling of groundwater
belonging to aquifer nº 23 through many wells, locally called “ojos” (“eyes”). Furthermore,
stagnant areas resulting from human activities (mostly watermill dams) altered the river
landscape. The interplay of surface and groundwater discharges, varying in space, time, quantity
and quality, was the most interesting feature of this ecosystem. Until thirty years ago, the
wetland comprised 6,000 ha but only 1,675 ha remain, which are included in the 1,928-hectare
Las Tablas de Daimiel National Park (Ciudad Real province).
Las Tablas de Daimiel are situated 606 m above sea level on La Mancha plain, which is
a geomorphological unit of Miocenic-Pliocenic, continental sediments. Limestones and marls of
lacustrine origin as well as sands, oozes, clays and calcretes are found in Las Tablas’ s area.
These alkaline materials have acted as impermeable substrates and together with the flatness of
the area, have given rise to hydromorphic, and sometimes saline, soils.
There are many solution forms in the surroundings of Daimiel. There are dolines and
uvalas some of which have big dimensions, with mayor axes up to 900 m and deeps of 10-15 m.
Organic limes and clays fill up the flat bottom of these karstic forms. The basins of some
temporal lake (El Escoplillo) still survive.
The river system is little developed and incises less than 20 m in the Llanura
Manchega. The main rivers are Azuer, Guadiana (which rose at the Ojos del Guadiana), Záncara
and Gigüela. This system is not functional today, not only for anthropic causes but because for
climatic reasons. During a recent past and in the Medium and Upper Pleistocene these rivers
drained the Llanura Manchega. An increasing aridity during the Upper Pleistocene reduced the
number of channels and let the fluvial system in the current residual situation.
The climate comes within the cold, temperature continental category with a dry season.
Isotherms range from 12-14ºC whereas the rainfall range is 400-500 mm, with a potential
average evaporation of 778 mm per year. Two dry periods (1895-1954, 1980-1995) and two wet
periods (1875-1894, 1955-1979) have occurred over the last hundred years.
Palynological analyses revealed hydrological changes in the area, reflecting periods of
either riverine or lacustrine dynamics.
Nowadays, flooding levels are markedly variable, albeit decreasing. Twenty years ago,
the usual cyclical pattern was a peak in Spring, decreasing slowly until Autumn when there
were high levels of flooding again. However, Las Tablas have become an infiltration area and,
hence, an area of water loss because of the demand for irrigation over the last decade, and this
has depleted aquifer nº 23.
Over the last ten years, the only water supply to Las Tablas has been through the
Gigüela River from the Tajo-Segura Aqueduct, a facility connecting the Tajo with the Segura
watershed. The Guadiana River has remained dry since 1986. An apparent increase of salinity,
brought about by both the lack of freshwater discharges and hypohaline groundwaters used to
feed the wetland in the worst dry periods of the year, has been recorded.
Nowadays, the potentially flooded surface in the National Park extends from northeast
to southwest. A breakwater dam (Quinto de la Torre), made with compact clays and gabions,
divide the Park in two areas (1147 and 528 ha). Las Tablas are today a great reservoir, which
dam, Puente Navarro, sites at the southwest boundary. Puente Navarro is a concrete and vault
dam; there sites the most extensive and deep (about 4.5 m) area of Las Tablas. There were
another deep areas along the ancient Guadiana stream, but many of them are silted up today.
The shallowest area is at the far end of the Park, at the Gigüela entrance.
There are more than 30 islands in the Park. The biggest ones (such as Isla del Pan and
Isla de Algeciras) site at the northeast area.
Today, remains of the canalisation built before the declaration of Las Tablas as National
Park can be observed in some points
Now, the aquatic environment is markedly irregular, highly turbid with high rates of
sedimentation. The chemical composition of waters is homogeneous, with sulphate and calcium
as the most important ions. There are high nutrient contents, eutrophisation indices (TP, SRP,
COD, inorganic nitrogen) suggesting that Las Tablas is a hypertrophic environment. In other
words, it is an ecosystem experiencing very high organic pollution coming from towns on its
watershed. Pollution from pesticide and heavy metals is, however, negligible.
Hydrochemistry studies show a salinity increase in Las Tablas. The freshwaters of the
Guadiana River diluted the high salt concentration of the water from the rivers Gigüela and its
tributaries, Riánsares and Záncara, which flow through gypsum soils. However, since 1986,
when the Guadiana River disappeared, this situation changed. The increasing drawdowns of the
aquifer and the long drought have been the causes because during the last years the only surface
flow has taken place through the Gigüela River. This stream has been used to transfer the water
from the Tajo-Segura Aqueduct to Las Tablas.
Another important aspect is the pumping of groundwaters in order to mitigate the
scarcity of water in the Park. It has increased the water’s salinity in Las Tablas due to the high
salinity of this water. It can be explained as a progressive salinization of the aquifer due to salt
accumulation processes in the sediment and its infiltration.
The maximum salinity levels have been normally measured between September and
November. However, there is a wide salinity variation along the year, which can be explained
because of the big fluctuation of the flooded surface in the Park, due to seasonal effects.
In general terms, phytoplankton and benthic algae comprise widely distributed species,
albeit rarely recorded in Spain in some cases, suggestive of hypertrophic, slightly saline
Macrophyte vegetation has decreases in terms of species´ richness and plant cover. In
particular, there has been a dramatic substitution of fen sedge formation, which needs a watery
environment for the roots, by reed and tomarisk, which are more tolerant of lack water.
Research into the animal life supports our diagnosis of a stressed environment.
Planktonic crustacea consist of very common species, suggesting an impoverishment of the
community and reflecting poorer water quality. It is important the decreasing number of species
of Mollusca, Tricoptera, Odonata and Plecoptera.
The fish fauna comprised 13 species until the creation of the Natural Park: carp, pike,
two barbel species, Iberian nase, chub, pardilla roach, tench, calandino roach, Moroccan loach,
mosquito fish, black-bass and freshwater blenny. Nowadays, only carp and mosquito fish
maintain stable populations because of pike introduction forty years ago, an increasing pollution
and the reduction in the flooding area.
Waterfowl have always been the distinctive feature of Las Tablas. This environment has
been on the Ramsar List since 1982 and the Spanish Government declared it Special Protection
Area for Birds (SPA) in 1979. The numbers of wintering birds (peak: 26,569 individuals in
1989) and nesting birds (peak: 5,497 pairs in 1988) are related to the size of the flooding area.
Decreases in diversity and population become obvious when one looks at birds censuses of the
La Tablas de Daimiel is sited in the municipalities of Daimiel, Fuente el Fresno,
Malagón and Villarrubia de Los Ojos. It is an agricultural area with plots mostly under 20 ha.
Crops are either dry farmed (barley, vine, olive) or under irrigation (barley, maize, oats, beet,
sunflower, alfalfa). Livestock is mainly sheep, cows being used for milk production instead of
meat. The human population decreased in the sixties due to emigration but has increases slightly
in recent years. Per capita income is lower than in Castilla-La Mancha and the Ciudad Real
Historically, the first records of settlements in the area (stone huts called “motillas” or
“morrillas”) go back to 3600-3400 B.P. Since then, there have been continuous human
settlements in the area, its influence being greatest in recent years. The available information
shows how an extensive area, which has experienced many civilisations over 36 centuries, has
been reduced two-thirds within a very short period (1965-1985) because of aquifer
overexploitation, drainage attempt and pollution.
As we have already told, the irrigation surface increasing since the decade of
70s from groundwater’s pumping put in danger the survival of the National Park. At the
beginning of the 90s, groundwater was pumping in order to flood a part of the Park during the
summer. These processes are reflected on the flood levels, which were over the unsaturated
zone until the decade of 80s and sometimes under it since then. The flood surface increased
when the Spanish Government approved a plan for the hydrological regeneration of the National
Park in 1988.
Figure 6 shows the water balance in the area in 1973-1974 and fifteen years later. The
main difference between then is the total quantity of water existing in the system (bigger in the
70´s) and the groundwater flow to Las Tablas. At the end of the 80´s, the sense is reversed and
surface waters recharge the aquifer.
The Spanish Government is committed to conserving Las Tablas de Daimiel National
Park. In order to avoid its environmental degradation, a Water Regeneration Plan has been
implemented with short-, medium- and long-term measures and a final goal of restoring earlier
groundwater levels. In the meantime, artificial management of this wetland must be accepted
(many wetlands are managed in this way), thus enabling it to fulfill its ancient role as a refuge
for the biodiversity associated with a wetland type that is threatened all over Europe, i.e.
riverine water tables.
To summarize, nowadays the minimum levels into the Park are artificially supported
through the groundwater pumping and with the sporadic transfers from the Tajo catchment,
which have changed the hydrochemistry of Las Tablas.
PEAT BOG AT THE GUADIANA RIVER IN ZUACORTA (excursion site 4)
PEAT BOG COLLAPSE IN MOLINO DE CHINCHÓN (CHINCHÓN WATERWHEEL)
(excursion site 6)
Limes and clays plenty of soil-organic matter, sands and peats constitute the alluvial
deposits of the Guadiana River between the villages of Daimiel and Villarrubia de los Ojos. In
this area (upstream its meeting with the Azuer River), the Guadiana River seems a karstic
depression more than a river. There are many dolines and uvalas and a great number of springs
which drainage the Llanura Manchega aquifer.
The peats have a Holocene age, probably less than 12,000 years. Periods of flooding,
with very rich waters in limes, calcium and to a lesser extent magnesium and chloride, from the
Llanura Manchega groundwaters, explain the origin of these deposits. The long periods of
flooding have allowed in these areas the formation of peat bogs a long the thalweg. It is frequent
to find calcium carbonate crusts and evaporitic deposits over the peats, probably because of
intensive evaporation processes during the summer and/or drawdown.
The peatland, which covers most of the 20 km of the former thalweg of the Guadiana
River, undergoes a slow process of spontaneous combustion. The configuration and geometry of
the sediments are hence very irregular and change in the time. There are several areas with
different characteristics: limes and very fine sands plenty of organic matter; burnt peats and/or
peats in combustion (at surface or at deeps to 3 m) where peat bog hasn’t been exploited;
vegetal soils sited in narrow belts on the banks of the river, higher than the pet bog; areas
without fires where the pet bog has been well exploited (the extraction has been made to deeps
where there aren’t fires or where the land has been steamrolled; burnt area and/or in combustion
where the peat bog has been exploited without planning (it has produced big holes which help to
the peat oxygenation and it is the most impoverished area because of the fires) (García et
The biggest peat accumulation areas seem to be associated to ancient “eyes” or to the
lower zones of the valley. The thickness of the peat layers is very variable, from 0,10 to more
than 2 m and present a lenticular shape. The limes associated to the pets have very variable
thickness too, reaching 3 m.
The aquifer drawdown (30-35 m) has caused the lost of the water that saturated the
peats and the other deposits. The total thickness has diminished because of the consolidation,
which produces a general subsidence and local collapses (they use to have a circular shape
because of the collapse of the caves’s roof). A new global subsidence is produced in the burnt
area due to the peat and organic soil’s oxidation and spontaneous combustion.
These materials autoxidize to low temperatures because of its high carbon content. The
peat autocombustión process is due to the formation of pirophoric amorphous compounds of
iron and iron oxides, which act as catalytic of exothermic reactions and initiate the combustion,
causing very toxic ashes and methane gas.
Fires use to produce preferential in greatest organic material thickness areas. They have
a very irregular distribution, probably conditioned by the sedimentary bodies geometry, by the
continuous drawdown and by the air entrance that help its oxidation. Karstic channels and peat
and quaternary porous allow the air entrance to the peat bog.
GIGÜELA RIVER IN VILLARRUBIA DE LOS OJOS: STREAM GAUGING STATION
(excursión site 5)
It is a stream gauging station belonging to the SAICA Alert Network (Sistema
Automático de Información de Calidad de Aguas - Water Quality Information Automatic
System). It controls the water entrance to Las Tablas de Daimiel National Park.
This network allows knowing the river condition and detects possible contamination
tops (due to forbidden spillages, contaminated human runoff, etc.) in real time.
In order to obtain the information special equipment and system are installed:
multiparameter analyser (pH, conductivity, temperature, dissolve oxygen); turbidimeters;
ammonium, nitrate, phosphate, total chrome, VI chrome, lead, cadmium and chloride analysers;
level and/or flow sensor; temperature sensor; automatic refrigerated sampler.
There is another auxiliary equipment: data acquisition system; VSAT communications
system; collecting system; microfilter system; water demineralization system.
The stations measure all the parameters constantly and transmit the information
(maximum, minimum, medium) through the satellite to the Catchment and Principal Centres,
where the vigilance is carried out.
These processes allow identifying the contaminated spillages and its author in a short
time, and hence having legal support for later economic sanctions.
CAMPO DE MONTIEL
1. – GENERAL FEATURES OF THE AREA
The high plateau of the Campo de Montiel (Field of Montiel) is located between the
provinces of Ciudad Real and Albacete, south of the Llanura Manchega (Manchega Plain) and
north of Sierra de Alcaraz (figure 7).
A field of limestone and dolomites of the low Jurassic form the plateau. It presents a
tabular structure that sinks by means of fractures towards the north, where is covered by
plioquaternary pediments and by manchego tertiary materials. Its thickness oscillates between
75 and 100 meters, although it can reach the 300 meters to the north and northeast. The Jurassic
assembly lies on an impermeable substrate of Triassic clays, marls and gypsum. The
topographic surface, smoothly undulated, varies from the 700 meters level to the north to the
1000 meters to the south.
The climate is Mediterranean semi-arid, with cold winters. There is little and irregular
rain and long periods of drought are frequent. Annual average precipitation is 460 mm, which is
higher in the southern zone of the aquifer due to the influence of the Sierra of Alcaraz.
Approximately 60% of years rain below the average (Various, 1997). Average temperature is 14
ºC, with a maximum of 34 ºC and a minimum of 1 ºC. As far as the ETP it varies between 700
and 800 mm.
The hydrogeological unit (04-06) that this calcareous field forms corresponds to the
aquifer of the Campo de Montiel (aquifer 24). Several rivers are born in this aquifer, and they
flow into three different hydrographic river basins: Guadiana, Guadalquivir and Júcar.
Generally, the draining network is not well developed and it displays an almost constant fitting
in all valleys because of the presence of an impermeable base. Fitted valleys that resemble
karstic tubes and small karstic heads of little development are observed. Most valleys of the
Campo de Montiel are torrents that take water only as a result of intense rain, especially during
summer storms. Rivers adapt to the jointed and fractured systems showing several main
directions: NW-SE and WSW-ENE; and another one, of less importance, approximately N-S.
This fluvial network, that is born in the field and flows to the river basins of the Guadiana,
Guadalquivir and Júcar, dissects the aquifer in several hydrological units. Finally, there is one
more important exit of water that goes underground to the aquifer of the Llanura Manchega
(Manchega Plain), north of the study zone.
The most important river crossing the Campo de Montiel is the High Guadiana, which is
born in the spring of Pinilla, at 980 meters elevation. It is one of the highest areas of the high
plateau, where it forms a small stream, the Pinilla River, which disappears by infiltration at
some points of its course. Several kilometers downstream the caudal increases suddenly,
originating the peculiar ecosystem of the Lagunas de Ruidera, declared Natural Park in 1979
The economic activity in this region has been historically centered in a precarious
agriculture of dry land (cereals, grapevine and olive tree) until in the eighties a series of
agricultural transformations took place, from dry land farming to others in irrigated land, thanks
to the groundwater exploitation. Due to the limestone and rocky nature of the area, there has
been little development of the soils in the Campo de Montiel. Crops have been mainly
implanted in valleys and “navas”, where the soil layer is slightly thicker. The groundwater
extractions in the head of the Park, along with an intense period of drought that extended from
the end of the eighties to the mid nineties, drastically diminished the levels of the aquifer. Most
of the springs that they fed the assembly of lakes dried, the superficial hydraulic connection
between the lakes was interrupted and many of them dried or were greatly depleted.
Due to this situation, in 1989 the aquifer was declared legally overexploited, being the
first case in Spain.
2. - GEOLOGIC, TECTONIC, AND GEOMORPHOLOGIC SETTING
The Campo de Montiel is located in the southern edge of the Castilian Plateau, between
tertiary and quaternary materials of the Llanura Manchega (to the north) and the mountain range
of intensely folded Jurassic materials of Sierra de Alcaraz (to the south). To the southwest, the
last northeastern spurs of Sierra Morena arise, a group of Paleozoic alignments with hercinic
directions and the volcanic region of the Campo de Calatrava (Field of Calatrava) (figure 9).
The geology of this area is integrated by a metamorphic hercinic basement on which
discordant Mesozoic sediments (Triassic and Jurassic) of low thickness are deposited.
The sporadic outcrops of Paleozoic basement in the Campo de Montiel demonstrate (by
its litology and structure) the natural prolongation of the hercinic units of Sierra Morena and of
the Campo de Calatrava towards the east.
Discordant with the Paleozoic quartzite and shales that form the basement of the Campo
de Montiel superposes the Triassic, which arises in great extensions south and west of the unit.
It consists of Germanic facies from the edge of the basin. Its upper section, that consists of
marls and red and green gypsiferous clays in Keuper facies, constitutes the impermeable
substratum where the carbonated materials from the Jurassic that form the aquifer of the Campo
de Montiel lie. From the hydrogeological point of view, the Triassic outcrops in the interior of
the aquifer are of great importance, since they function as dividers and reveal springs associated
to the contrast of permeability between these materials and the calcareous ones. This outcrop
has been related to stratigrafic causes, with diapiric phenomena due to the plasticity of these
materials and, in recent works, to ascents favored by the intense fracturing that affects the cover.
On the impermeable bottom lies a calcodolomitic and marly series that displays a
subhorizontal tabular structure and conforms the Campo de Montiel. Its age has been attributed
to the low Jurassic (Lias) by its position, facies and correlation with neighboring areas, since no
paleontological criteria have been found. Its study presents difficulties due to the existence of
dolomiting and brecciation processes. In addition, the series are not complete because of the
lack of sedimentation and/or erosion. There have been described three litostratigrafic
formations: a) Lower Lias: calcodolomitic formation that constitutes the main aquifer of the
area; it leans directly on the Keuper and its thickness oscillates between 60 and 100 meters; b)
Medium Lias: marl-argillaceous assembly whose thickness is variable and difficult to determine,
considering about 50 meters as an average. Upwards there is a constant lumaquelic level very
dolomitized; and c) Upper Lias: calcareous assembly (about 20-40 meters thick) with some
marl-limestone intercalated sequences, whose main characteristic is the presence of abundant
oolitic levels. Likewise the Medium Lias, it arises east of the area.
The most characteristics tertiary facies in the area correspond to red breccias and limes,
conglomerates and carbonates; very similar in aspect to the Lower Liassic section. The quarcitic
conglomerates are from the plioquaternary age with clay-sandy matrix of intense red color,
which can contain cobbles of diabase, granites and shale. Finally, the Quaternary is represented
by diverse travertine and conglomerates and argillaceous alluvial deposits.
Historically it has been considered like a non-tectonic region without hardly any
deformation, that was part of what has been denominated the “Albacete’s stable platform”.
Nevertheless, the last studies demonstrate that its thickness is very variable and that it is
affected by fractures, folds and diapiric processes (bound to the activity of main fractures),
which chamber the aquifer and condition its hydrologic operation (Montero, 1994 and 1995;
Rincón et al., 1996). Folds and fractures were not mapped previously because they were
fossilized by coverings of tertiary and quaternary materials that, in many cases, present similar
lithological characteristics to those of Jurassic materials, with which have been confused (figure
The limits of the aquifer are clearly defined west and south, but not east and north,
although, in the four cases, their directions are related to main tectonic directives: the southern
and northern borders show a WSW-ENE direction, whereas the western and eastern ones have a
The physiografical and hydrogeological unit of the Campo de Montiel has been under a
moderate compressive deformation throughout the neotectonic period, coherent with the last
dynamics of the African and Euro-Asiatic plates. The considerable interrelation between
structural, physiografical and hydrogeological aspects is explained in a flexural litospheric sense
(Rincón et al., 2001b).
The morphology of the hydrogeological unit, its internal hydrogeological subdivisions,
the sense of groundwater flow, the spatial disposition of the springs, or the narrow relationship
existing between superficial and groundwaters, are of clear tectonic conditioning. In addition,
there is a fitting of the fluvial courses in favor of the main structural discontinuities (faults
and/or joints) contemporary with the deformational events or reactivated by these: processes of
karstification clearly conditioned by the tectonic context. Finally, under this flexural proposal
also fits an explanation to the endorheic or semiendorheic character of the High River basin of
the Guadiana, proper of an irregular and immature surface, structured at recent times: successive
antiformal and sinformal flexures (with diverse wavelengths and a fragile surface expression).
The tectonic origin of the division of waters in the Campo de Montiel’s aquifer towards three
different hydrographic river basins seems also evident (Rincón et al., 2001a and b).
3. - GENERAL HYDROGEOLOGY OF THE AQUIFER
The main aquifer of the hydrogeological unit is formed by limestones and dolomites of
the Lower Lias, with a high permeability by fracturing and dissolution, and that presents the
maximum transmissivities in the central zone: head of the Lagunas de Ruidera. Something less
permeable is the oolitic limestone of the Upper Lias that extend to the easternmost zone of the
Campo de Montiel although show a high transmissivity southeast of the aquifer. The limestone
and calcareous breccias from the superior Tertiary, outcropping in the center-western part, also
form small hanged aquifers.
The base of the hydrogeological unit is constituted by impermeable materials from the
Upper Triassic (clays and evaporites in Keuper facies), that arise to the west, south and
southeast. Triassic outcrops within the aquifer are also numerous (figure 9).
The aquifer of Campo de Montiel is a unconfined aquifer, with an extension of 2,575
km 2 . The only recharge of the aquifer is precipitation falling directly on it, since connection
with other units does not exist. The high permeability of the calcareous materials of the Campo
de Montiel allows most of the water coming from precipitations to infiltrates the aquifer, reason
why the surface run-off on the calcareous field is almost null. The discharge of the aquifer takes
place through springs, some located between the carbonated permeable materials and the
impermeable substratum, others originated when the topography cuts at the phreatic level and
others in the contact between permeable limestone with some smaller permeability level within
the calcodolomitic series. Most of the springs show a narrow relationship with fracturing; the
ones with higher rates of discharge (Hazadillas, Ossero, Ponzoñón) are associated to
intersections of fractures.
The most important springs give rise to rivers and streams (Pinilla- High Guadiana,
Cañamares, Azuer, Segurilla, Jabalón, Córcoles, Sotuélamos) whose regime is regulated by the
The Campo de Montiel can be classified as a diffused flow aquifer. The relatively low
solubility of the dolomites implies little dissolution activity, reason why the flow is not
concentrated in large conduits, there are few caves and these are disconnected among them.
What seems clear is that the framework of fractures that affects the aquifer exerts a control in its
functioning, causing high secondary porosity. This results increased by the phenomena of
dissolution caused by groundwaters when widening the fractures and the original planes of
stratification. Permeability is conditioned by the location of the conduits or fissures, which
depend as well on the lateral changes of facies, the initial permeability or the existence of
fractures widened by dissolution. As a result, the aquifer usually displays great anisotropy.
Thus, obtaining groundwater is difficult, existing great differences as far as the efficiency of
wells located near each other (Montero, 1994).
The transmissivity of the aquifer presents important variations: the highest values occur
in the head of the Lagunas de Ruidera and southeast of Campo de Montiel (500 to 2000 m 2 /day,
reaching 6000 and 7000 m 2 /day occasionally). In the northern, the western and southwestern
areas of the aquifer transmissivity is much lower, between 10 and 100 m 2 /day. The highest
values coincide with those zones where the maximum extractions are conducted, whereas the
lowest occur in areas in which most of wells have been abandoned (Martinez et al., 1992). The
storage coefficient varies between 1 and 5 %.
The study of the aquifer’s geometry by means of the analysis of numerous litologic
columns and of previous geophysical investigations, has detected several Triassic thresholds
that separate the aquifer zones and that create hydrogeological units that behave with almost
total interdependence among them (Montero, 1994; 2000). The impervious Triassic thresholds
of major spread detected in the aquifer are in the strip Villahermosa-Viveros (figure 9), a long
the Lagunas de Ruidera, north and northwest of Ossa de Montiel and surrounding El Bonillo.
All of them can be related to fractures, some by being located in zones of intense fracturing,
others by being circumscribed to large fractures and others by being aligned according to the
main tectonic directives (figure 10).
South of the aquifer the springs are located in contact with permeable materials of the
Jurassic and the impermeable ones of the Upper Triassic. There is an important thickness of
permeable materials below the drainage level in this area, which allows storage of the
groundwater. These characteristics, along with the high transmissivity of the aquifer, allow the
extraction of elevated volumes of water in wells. However, the altitude at which the springs are
located on the impermeable base means that a reduction of a few meters in the water table can
decrease the volume of the springs or dry them (Montero, 1994; 2000).
In the High Guadiana valley, the springs are not associate with the Jurassic-Triassic
contact, but that originate when cutting the topography at the piezometric level. Therefore,
elevated springs dry out when the water level in the aquifer descends, which diminishes the
contributions that in normal conditions the highest lakes receive. When this happens, a
weakening of the hydraulic connection between the lakes takes place, reducing the transferred
discharges to inappreciable values. In certain zones of the aquifer, the geologic structure itself,
the existence of fractures that elevate the impermeable bottom or the erosion of valleys allow
the existence of springs at the impermeable level. This seems to happen in the proximities of the
spring of Pinilla or in the western limit of the aquifer. In these zones, the springs display a
relatively regularized regime, maintaining their volumes practically constant throughout the
Generally, it can be admitted that the aquifer can store great amounts of water, but it has
little capacity of regulation, since natural elements of impermeable nature that retain it do not
exist. A slow unloading of the aquifer takes place if precipitation stop or extractions for
irrigation are increased. On the other hand, it is an aquifer with a great recharging capacity,
recovering its level in less than a year and presenting an overflowing situation a few months
later (like most of the karstic aquifers).
4. - EXCURSION SITES
NATURAL PARK OF THE LAGUNAS DE RUIDERA (excursion site 7)
During the Second Spanish Republic (1933) it was declared Natural Site of National
Interest. With the Law of Protected Spaces it received the qualification of Natural Park in 1979.
It is also subject of a Special Plan for Protection approved in 1981. The Junta of Communities
of Castilla La Mancha is the organism in charge of the protection of the Natural Park since
An assembly of 15 lakes aligned in a NW-SE direction and connected to each other by
channels, gullies, and cascades or springs forms the main valley that constitutes the park. They
appear stepped throughout about 35 kilometers, being the difference of level between the first
and last one 120 meters approximately. Starting from the first ones, upstream, their names are:
Blanca, Concejo, Tomilla, Tinaja, San Pedro, Redondilla, Lengua, Salvadora, Morcilla or Santo
Morcillo, Batana, Colgada, del Rey, Cueva Morenilla, Coladilla and Cenagal or Cenagosa
They are usually grouped in two assemblies of different characteristics: low and high
lakes. The high lakes, in which the Pinilla river appears again, are located upstream of the town
of Ruidera. In this assembly the largest and deepest lakes are found (some reach 21 meters
deep); each of them is closed by means of a travertine limestone building that acts like a natural
barrier, damming the water which forms a cascade when the system receives sufficient water
from the aquifer. During most of the nineties only the cascade of El Hundimiento remained
active, in the great bar that separates the high from the low lakes. During the summer of 1996,
as a result of the high water levels in the aquifer, the cascades began to appear again, reaching
the lakes the maximum volumes in January of 1997.
The low lakes are short and their travertine barriers are degraded. They are surrounded
by rushes and reeds that practically invade the Cenagal (Quagmire) lake, whose name comes
from the characteristics of its bottom. After this last lake the water continues digressing by a
marshy valley until it is channeled near the tail of the dam of Peñarroya. Downstream of the
dam, the river left the field to enter the Llanura Manchega. Once there, the water disappeared
gradually by evaporation and infiltration in permeable lands of the plain. Nowadays, and
through a network of channels and drains, it is distributed to a large irrigation area in the
municipalities of Argamasilla de Alba and Tomelloso. At times of high rainfall, the spillover of
the dam circulates in the Guadiana River infiltrating a few kilometers ahead in the aquifer of the
The assembly of lakes represents 300 has. The total volume dammed in 1989 was about
23 Mm 3 (according to the bathymetric study of the lakes made by the HYDROGRAPHIC
CONFEDERATION OF THE GUADIANA). The dam capacity is slightly larger since at this
date the levels in the lakes no longer reached the spill point.
Taking advantage of the unevenness of the water between the different lakes, diverse
hydroelectric power stations were constructed, most of them are no longer used today, with
jumps between 15 and 25 meters and productions between 80 and 1500 kWh.
The described geographic frame serves as habitat for the development of a singular flora
The vegetation is well adapted to the extreme climate existing in this area (great frosts
in winter and warm and dry summers). Two different ecosystems are found: paludal and forest.
Paludal, next to the lakes, is made up of species with submerged roots most of the year or seated
on very humid ground. Several strips of vegetation are distinguished according to their level of
dependency of the water. The halophytic vegetation, that hides some lakes like the Cenagal or
Coladilla by its exuberant development, has undergone enough aggressions in all the Natural
Park and is regretting due to road and beach construction, to the swimming tourism, to
contamination and to periodic burning, reason why it tends to disappear in most of the shoreline.
This type of paludal vegetation has an extraordinary power for purifying water and, in addition,
it is the refuge and place of nest building for all the aquatic birds in the lakes.
The typical perennial vegetation of the plateau, showing the complete series of an oak
forest, characterizes the forest ecosystem. Nowadays, this ecosystem is one of the last remains
of the original vegetation of La Mancha, favored by the influence of the water mass. The aquatic
zone of the park has undergone a strong impact in past few years, and the slopes of the valley
have been suffering aggressions for a longer time. The continuous and massive cuttings for
carbon production and the uncontrolled pasturing in the past centuries, along with the
construction of urbanizations and the cuttings to implant new farming areas, have destroyed
great part of the oak forests leaving loose specimens that, in some cases, are millenarian and
Regarding the fauna, it has to be emphasized that noise, pollution of waters and
colonization of adjacent forests (one of the main refuges of the birds) have caused it to back
down towards recondite places outside the park, or towards its left margin which is less
colonized. Among the aquatic birds present in Lagunas de Ruidera are: pochard, tufted duck,
red-crested pochard, mallard, teal, shoveler, gadwall, pintail, coot, great crested grebe, little
grebe, and moorhen. There are also species listed of special interest: osprey, booted eagle, shorttoed
eagle, Bonelli´s eagle, buzzard, goshawk and purple gallinule and, as a species in danger of
extinction, the black stork. In the aquatic ecosystems of the lakes there are common carps,
muskies, green frogs, common toads and white storks.
The forest ecosystem is characterized by the presence of lagomorphs, especially rabbits.
The red-legged partridge is also typical (there are numerous hunting grounds). Other common
birds in the zone are the azure-winged magpie, woodpeckers and swifts.
The Peñarroya swamp gathers most of the water that drains the Lakes. As a result of the
climate, contributions are very variable. Only one every three years they surpass the average of
the last sixty years (90 Mm 3 ). The maximum registered since 1931 was 2,570 Mm 3 in the year
1946-47 and the minimum 15 Mm 3 in 1944-45. Besides the volume and distribution of
precipitations fallen in the year, the unloading of the aquifer is influenced by its loading level,
since after a period of drought part of the water is used to fill up the empty cavities of the
In the period between 1984 and 1987 the transformation in irrigated land (from
groundwaters) of the Campo de Montiel takes place, plowing sometimes forestlands populated
with oaks and “sabinares”. The major exploitations are located in the head of the Natural Park.
This transformation negatively affected the water contributions of the Lagunas de Ruidera, in
the quantity (superficial hydraulic disconnection, dry lakes or with very low levels) and in the
quality of waters due to the percolation of fertilizers and pest-control substances used in
extensive agriculture of irrigated land (increased nitrate content). In 1987 there were 25 Mm 3
extracted from the headstream opposed to the 90 Mm 3 average contributions of the lakes.
The coincidence of lower-than-average precipitations, along with the increment of
extractions from wells for irrigation, triggers a process of generalized decrease of the water
levels of the Lagunas de Ruidera, some of which dried out. Between 1986 and 1995 a slow but
continuous discharge of the lakes took place. In 1986 a gradual decrease of the water levels
begins, reaching a drop of 10 to 15 meters in the level of wells located in the head of the system.
Due to this situation, in 1989, the aquifer is declared legally overexploited, which
implies limiting water for irrigation to an annual maximum and also the determination of an
annual volume of water to be extracted for irrigable in aquifer by means of an annual extraction
planning. The objective of this plan was to diminish the impact of irrigation in the levels of the
lakes and to guarantee irrigation for the lands downstream from the system (by means of the
volume dammed in the reservoir of Peñarroya). Protected by the CEE Nº 2078/92 regulation of
the Council about methods of agro-production compatible with the conservation of the
environment and of natural resources, a compensation program of agrarian rents for farmers was
approved in 1993, so that they would reduce their irrigation dowries to recover the levels of the
Lagunas de Ruidera. The continued drought prevents the increase of the water levels until the
autumn of 1995, when precipitations in the entire region begin to take place. Soon after water
begins to run in streams and fountains that had been dry for several years. After strong storms in
the autumn of 1995 the springs in the head of the Park began to flow, although water infiltrated
again filling up the karstic cavities, beginning to flow regularly once these cavities were full.
Eight months after the precipitations begin the process of filling of the lakes and the aquifer was
completed, obtaining total superficial connection of all the lakes.
There is an important thickness of jurassic and quaternary materials in the substrate of
Lagunas de Ruidera that allow the circulation of water underneath, although in some areas the
tectonic and diapiric processes elevate the impermeable threshold of the Upper Triassic
preventing or making difficult the flow (figure 11). In addition, the elevation of the Triassic
materials in the right margin by means of fractures restricts the flow from the aquifer to the
intermediate and low lakes.
The water level at the aquifer, the geometry of the lakes and the geologic characteristics
of its substrate condition the water level in Lagunas de Ruidera. Based on their hydrologic
behavior four assemblies of lakes can be established (Montero, 1994):
The highest, fed by a very transmissive sector of the aquifer, reflect its piezometric
level. For that reason, the topographically elevated points like the Laguna Blanca and its
surrounding springs dry out when the water level in the aquifer descends. The lakes Concejo
and Tomilla continue being "winners" and their levels only descends when the aquifer is very
low, since they are located beneath the phreatic surface. The reductions in the piezometric level
cause superficial water transfer to stop, within this assembly and in the following one.
The second assembly, formed by the intermediate lakes, from Tinaja to Batana, is fed
mainly with superficial contributions from the high lakes and when this is interrupted, it begins
to drain. The high gradient that the piezometry in this section displays indicates a decrease in
transmissivity of the materials that form the base of these lakes. There is a groundwater flow
under the assembly, although it seems to concentrate in conduits and/or more permeable zones.
The lakes Colgada and Rey form the third group. Its feeding is superficial, from transfer
from the second assembly of lakes and from the valley of the Hazadillas (where there are some
of the springs with a higher flow). The elevated position of impermeable materials of the Upper
Triassic makes difficult the groundwater cession from the previous assembly but it allows the
water to remain dammed. This is the reason why the water level does not experience any
variation even if the transfer of superficial water is interrupted.
The impermeability of the bar located between these lakes and those of the fourth
assembly, "low lakes" cause the hydraulic disconnection between both groups. Feeding of the
last lakes takes place, almost exclusively, in a superficial manner.
The system of superficial transfer between the lakes only works in times of very high
phreatic levels. When it is interrupted (what occurred between 1986 and 1996) the lakes of the
intermediate section are the first ones affected, drying later those of headstream; the low lakes
are the less affected (Montero, 1994, 1995 and 2000).
WINERY IN TOMELLOSO (excursion site 8)
Grapevine and wine production in Spain is high and great part of it concentrates in the
Manchega region. This creates a problem, among others, with generation of a significant
volume of wastes from derivatives of the grape from the distilleries. These left over (whatever
the raw material of origin) are called “vinazas” (strong wine) and they were spilled into the
environment, without any previous processing, using several systems (Servicio Geológico,
1988): a) Network of sewage system: the remainder was spilled to superficial waters or green
filters (spilled in surface); b) Caves: vinaza unloading in shallow caves, (spilled in the
unsaturated zone: caves of Tomelloso); c) Old chain dumps: vinazas were spilled in shallow
excavated wells that have dry out (spilled in the unsaturated zone); d) Wells: the spill was
injected in soundings with depths below 100 m (spilled in the saturated zone: deep wells in
Daimiel and Tomelloso); e) Rafts: they were used fundamentally in the spill of vinazas of lias,
since the high concentration of solids in suspension of this effluent makes unviable its
evacuation by other means.
In La Mancha, a traditional method to dispose of urban and industrial residues has been
to introduce them in the subsoil. However, this did not cause any serious problems since urban
residual water volumes were low and they ended up in the sewage network, and industries were
small and familiar.
Growth of population centers and industrial development caused the small wineries to
disappear. Huge factories, which caused a strong increase in the volume of remainders, replaced
them and concentrated the spills in restricted zones.
Regarding excursion site 8, there are eight important distilleries in Tomelloso. One of
them spilled in an injection drilling 90 meters deep, five in wells 25 meters deep and two in
caves of vinazas (figure 14).
By the end of 1985, a plant for processing vinazas and producing biogas began to work
in this locality. The biogas function is to accelerate the process of fermentation of vinazas in a
controlled manner and on industrial scale. This is achieved in anaerobic digesters by means of a
bacterial bed, so that their concentration per cubic meter is elevated. The methane produced as a
result of this fermentation is lead to the users by the distilleries.
The industries from La Mancha dedicated to wine distillation process ethyl alcohol like
fundamental product and, in certain cases, generate by-products that they use as raw materials to
make “orujos” (liquor distilled from grape remains), “heces” or “lias” and wines of low
The main products extracted from the grape are shown in figure 12. In addition to wine,
it can be seen that production of alcohol from the different remainders is very frequent: wines of
low quality, orujos (joint of peels, seeds and floral peduncles of the clusters that stay as
remainders of the obtained juice), heces or lias (sediment in the wine production) and mattocks
(dissolution obtained from the maceration of orujos in water).
From the quantitative point of view, vinazas present important variations based on the
origin of the raw material, the industry that produces them and the harvest. Vinazas of mattocks
display a high content in soluble organic matter, and relatively low and easily biodegradable
suspended matter. Vinazas of lias constitute the most polluting effluent, containing a high load
of suspended solids of organic origin and they are easily biodegradable. Regarding vinazas of
wine they have a high content in biodegradable organic matter and a reduced load of suspended
The physical and chemical composition of vinazas is very complex. Its main
characteristics are: very low pH, between 3 and 6; a OQD that can exceed 30,000 mg/l; an
organic matter content between 9,000 and 35,000 mg/l; potassium values that surpass the 2,500
mg/l; phenolic compounds to up to 1,000 mg/l; temperatures that can reach 90 ºC, etc. These
characteristics confer the spill a distinct acid and reducing character.
The acidic character causes karstification phenomena, due to the calcareous component
of the land. The reducing character favors the formation of the gases CH 4 and CO 2 in anaerobic
conditions, which can produce explosions if it occurs in a closed environment. Therefore, the
representative parameters of this type of pollution are: potassium, relation SO 4 /CO 3 H - , nitrates,
tannin and lignin, and total organic carbon.
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contaminantes”. Informaciones y Estudios nº 49. MOPU.
VARIOS (1997). “Parque Natural Lagunas de Ruidera”. Editorial Cohábitat. 395 pp.
Figure 1: Geographic location of the study area (Llanura Manchega) (Source: Servicio Geológico, 1988)
Figure 3: Schematic geologic profiles of the Llanura Manchega. Quaternary - 1: pebbles, sands, silts, etc.
Plioquaternary - 2: conglomerates, pebbles, sands, etc. Pliocene - 3: limestones and limy marls. Miocene - 4:
limestones and marls; 5: red clays. Cretacic - 6: limestones; 7: sands and sandstones. Jurassic - 8: limestones,
dolomites and marls. Triassic - 9: clays, gypsum and sandstones. Palaeozoic - shales and quartzites (Source: Servicio
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 39-
FIELDTRIP TO ARAGÓN
Sánchez, J.A.; Pérez, A.; Roc, A.C., and Rubio, J.C.
Department of Earth Sciences. Faculty of Sciences. Zaragoza University. 50009 Zaragoza (Spain)
La Comunidad Autónoma de Aragón está situada al NE de la península Ibérica, su capital
es Zaragoza, que se sitúa a mitad de camino entre las ciudades de Madrid y Barcelona. Desde el
punto de vista geológico, en Aragón existen tres grandes unidades (Figura 1): los Pirineos, la
Cordillera Ibérica, y la Cuenca Terciaria del Ebro.
Figura 1.- Esquema de situación de las zonas de Campo. El número indica el día de visita
En esta guía se presenta un itinerario que atraviesa en dirección Norte-Sur las citadas
unidades geológicas. Este itinerario es principalmente hidrogeológico y está especialmente
referido a las aguas termales. Además se completa con otras zonas de especial interés geológico
Las zonas y temas seleccionados son los siguientes:
Primer día de campo:
-LAS AGUAS TERMALES DE ALHAMA-JARABA
-LA CUENCA ENDORREICA DE LA LAGUNA DE GALLOCANTA
Segundo día de campo:
-LA UNIDAD ACUÍFERA DE ALFAMEN COMO EJEMPLO DE ACUÍFEROS
-LOS MANANTIALES DE PONTIL COMO EJEMPLO DEL DRENAJE
SUBTERRÁNEO DE LA CORDILLERA IBERICA EN LA DEPRESIÓN TERCIARIA DEL
Tercer día de campo:
-LAS AGUAS TERMALES DE PANTICOSA
-EL SINCLINAL DE JACA Y EL MANANTIAL TERMAL DE TIERMAS
PRIMER DÍA DE CAMPO:
LAS AGUAS TERMALES EN ARAGON: DATOS BÁSICOS PREVIOS
El estudio sobre la Aguas Termales de Aragón (Sánchez et al. ) ha permitido inventariar
todos los indicios hidrotermales existentes (manantiales, sondeos...) y cuantificar la energía
geotermal que por convección surge por cada uno de los manantiales. La figura 2 muestra para
todo Aragón, la situación de cada uno de los manantiales termales existentes, junto con un
círculo que es proporcional a la energía termal aportada. La ecuación utilizada para evaluar esta
energía es la de Pfister, M., et al., (1998) que evalúa la energía que cada segundo está saliendo:
E = ∆T x Q x Cx ρ
Donde: E es la energía en Megawatios que de forma natural surge por los manantiales. ∆T es la
diferencia entre la temperatura medida en la surgencia y la temperatura media del aire, que sólo
se considera si es mayor de 4ºC. Q es el caudal en l/s. C es el calor específico del agua que tiene
un valor de 4200J/kgºK. Finalmente, ρ es la densidad del agua cuyo valor es 1000 kg/m 3 .
Figura 2.-Situación de los manantiales termales existentes en Aragón
A modo de resumen se acompaña una tabla con los datos básicos de los principales
Este estudio ha permitido también definir las formaciones geotermales de Aragón, que
son los materiales geológicos capaces de almacenar y transmitir agua u otros fluidos a una
temperatura que permitan su aprovechamiento (uso balneario, calentamiento de espacios,
energía eléctrica...) La figura 3 muestra estas formaciones referidas por una parte al Pirineo y
por otra a la Cordillera Ibérica y la cuenca Terciaria del Ebro.
Figura 3.- Columnas estratigráficas y formaciones geotermales de la Cordillera Ibérica y del Pirineo
LAS AGUAS TERMALES DE ALHAMA-JARABA
Los manantiales termales de Alhama y Jaraba se encuentran en la Cordillera Ibérica, en
el contacto entre la parte oriental de la cuenca de Almazán y el borde sur de la Rama Aragonesa
de la Cordillera Ibérica. Son un conjunto de manantiales que se caracterizan por su elevada
temperatura, hasta 35 ºC y su importante caudal, en conjunto superan los mil litros por segundo.
Estos manantiales son la principal alimentación de los río Mesa en Jaraba y Jalón en Alhama.
La figura 4 muestra la situación geológica de estos manantiales y la relación con las
estructuras que condiciona su surgencia. Como puede verse el acuífero principal corresponde a
los materiales carbonatados del Cretácico Superior (Formación Geotermal nº 6, Fig. 3), por ellos
circula el agua subterránea siguiendo su estructura, de manera que en ocasiones desciende a más
de mil metros por debajo de la superficie del terreno (ver cortes 1 y 2), el relleno terciario
constituye un acuitardo de gran superficie y extensión. Destacar que las surgencias se localizan
en estratos carbonatados del Cretácico dispuestos verticalmente, de manera que esa estructura
aflorante (ver fotografía) se continúa varios cientos de metros en profundidad. Es precisamente
esa estructura la que permite que el agua, calentada en profundidad, ascienda manteniendo
todavía una temperatura anormalmente alta.
Figura 4.-Situación geológica de estos manantiales en Alhama-Jaraba y la relación con las estructuras que
condiciona su surgencia.
Todo el contacto entre la cuenca terciaria de Almazán y los materiales del Cretácico
superior tiene una disposición similar (ver cortes 1 y 2) de manera que además de los
manantiales de Alhama y Jaraba existen otros en el citado contacto: manantial de Deza con un
caudal de 100 l/s y 19 ºC de temperatura, manantial de Embid de Ariza con 20 l/s y 27ºC, y
manantial de San Roquillo con 20 l/s y 19ºC. Un dato importante es la cota a la que se
encuentran estos manantiales.
La recarga de este acuífero Cretácico se produce en la cabecera del Jalón, a través de
principalmente de materiales calizos del Jurásico. También es importante la recarga que se
produce de forma difusa a través de los extensos depósitos detríticos terciarios de la cuenca de
Almazán. Sobre este tema, y sobre el flujo del agua hacia los manantiales existe una discusión
científica, existiendo una teoría que considera que el agua no circula por debajo de la cuenca
terciaria, sino que sigue la dirección de los afloramientos del Cretácico Superior (ver discusión
de J.A. Sánchez et. al, y la réplica de E. Sanz et al., en Groundwater, vol. 38, nº 3, 324-325 pp.)
Los manantiales termales de Alhama y Jaraba presentan composiciones sulfatadasbicarbonatadas,
cálcicas o cálcico-magnésicas. Las aguas de Alhama son las más mineralizadas,
como un residuo seco entre 650 y 850 mg/l, mientras que las de Jaraba no superan los 650 mg/l.
La figura 5 muestra en un diagrama de Piper la situación de los diferentes manantiales, como
puede verse las aguas termales difieren notablemente de las aguas procedentes de manantiales
Destacar como los manantiales de mayor caudal (los de Alhama y Jaraba) presenta
composiciones más sulfatado-cloruraras y magnésicas.
Las aguas de estos manantiales tienen un uso balneario, en Alhama existen tres
balnearios y en Jaraba otros tres. Algunos de los manantiales están calificados como mineromedicinales
y además del uso terapéutico, se embotellan para su comercialización, en Jaraba
existen 3 plantas para embotellados de agua. Por otra parte, las aguas de estos manantiales son
recogidas por acequias y con ellas se riegan más de 1000 ha principalmente de frutales.
Figura 5.- Diagrama de Piper-Hill-Langelier de los manantiales de Alhama, Jaraba, San Roquillo y Embid
PARADA 1 (Alhama de Aragón).-
Vista de los estratos carbonatadas del Cretácico Superior, en disposición vertical que
dan lugar a los manantiales termales. Observación del contacto entre el borde de Cuenca
Terciaria y los materiales del Cretácico Superior. Comprobación de la temperatura de uno de los
manantiales termales. Vista del pliegue de Alhama.
PARADA 2 (Jaraba).-
Visita a Baños de Serón y comida. Recorrido a pié hasta el balneario de Sicilia y el lago
termal en Balneario de la Virgen.
Se acompaña plano del itinerario (Fig.6) y diagrama de Piper de todos los manantiales
(Posible visita a la piscina termal).
Después de observar el notable descenso del caudal del río Mesa aguas arriba de Jaraba,
iniciamos el camino hacia la laguna de Gallocanta.
Figura 6.- Itinerario de la zona de Jaraba
Figura 7.- Diagrama de Piper-Hill-Langelier de los manantiales de la zona Alhama-Jaraba
Figura 8.- Acuífero carbonatado Mesozoico
LA CUENCA ENDORREICA DE LA LAGUNA DE GALLOCANTA
La laguna de Gallocanta es el mayor humedal salino del Noreste de la península Ibérica,
con una superficie de unos 14 km 2 . Presenta una profundidad máxima de 2 metros, llegando a
sequedad total en verano. La composición y caracterización hidroquímica de sus aguas muestra
que Gallocanta es un lago hipersalino de tipo Na-Mg-Cl-(SO4) con una mineralización que
supera los 50 gramos/l y que durante periodos secos presenta un enriquecimiento en sales como
halita, bischofita, epsomita, hexahedrita y mirabilita. Las aguas proceden de flujos subterráneos,
existiendo además cursos torrenciales que aportan aguas superficiales.
Su importancia como lugar de descanso para aves migratorias procedentes del norte de
Europa le han dado un elevado valor medioambiental, está declarada como Zona de Especial
Protección para las Aves, y se está tramitando su transformación en Parque Natural.
La conservación de la laguna, junto con su prados húmedos ha entrado en conflicto con
la explotación de las aguas subterráneas para regadío, provocando problemas entre los
habitantes de la zona y las administraciones públicas. La Comunidad Europea subvenciona una
sobresiembra de semilla de cereal para permitir la alimentación de las aves, especialmente de las
Grullas, pero los agricultores siguen considerándose perjudicados.
La laguna de Gallocanta se encuentra en una altiplano a 1050 m. de altitud, rodeado de
montañas de unos 1400 m que constituyen la divisoria de aguas superficiales de su cuenca
endorreica que tiene unos 500 km 2 de extensión.
Son más de 10 barrancos los que confluyen a la laguna, pero sólo dos de ellos llevan
agua casi permanentemente. La precipitación en la zona es escasa, entre 400 y 600 mm/año, y la
evaporación intensa, más 1000 mm, lo que hace que durante la época estival la laguna quede
totalmente seca. Se constata la existencia de una notable aportación de aguas subterráneas a la
laguna, las cuales parece ser que debido a los bombeos han quedado fuertemente reducidas en
los últimos años.
Se han definido dos acuíferos principales, (ver fig. 8 y fig. 9) el acuífero carbonatado
Mesozoico, y el acuífero detrítico de Gallocanta.
Acuífero carbonatado Mesozoico.
Corresponde a calizas y dolomías del Jurásico y Cretácico, como puede verse en la Fig. 8
afloran según una dirección NW-SE, ocupando una extensión de 200 km 2 , de los cuales 160 km 2
se sitúan dentro de la Cuenca de Gallocanta, su espesor medio de unos 140 m.
En este acuífero se han inventariado más de doscientos puntos de agua de los que el 46%
son pozos, el 31% sondeos y el 23% manantiales. A estos puntos habría que añadir la presencia
de varios sumideros. El caudal de explotación y/o drenaje es muy variable, así los manantiales
rara vez superan los 10 l/seg, mientras que los pozos y sondeos suelen tener algo más de caudal,
llegando a superar en algunos casos los 50 l/seg.
La transmisividad de este acuífero oscila entre 100 y 250 m 2 /día, llegando
excepcionalmente a valores de hasta 1000m 2 /día. En cuanto a su coeficiente de almacenamiento
es muy variable, oscilando entre el 0,01 al 3%, considerando un espesor medio saturado de unos
30 m, las reservas de aguas subterráneas se estiman en unos 30 hm 3 .
En la figura 8 se muestran los puntos de agua inventariados y el mapa de isopiezas de
este acuífero; Como puede observarse el flujo dominante es hacia la laguna en el entorno de
ésta, pero tanto hacia el este como hacia el oeste el flujo se dirige hacia las cuenca vecinas,
parece claro por tanto que la divisoria de aguas subterráneas no coincide con la divisoria de las
superficiales. Por otra parte, las variaciones estacionales son muy acusadas, presentando una
respuesta rápida a las precipitaciones. La divisoria de las aguas subterráneas puede ser variable
en el tiempo.
En cuanto a las características físico-químicas de las aguas, predominan las de
composición Bicarbonatadas cálcicas, aunque en algunos casos se observa una fuerte
mineralización, con un alto contenido en SO 4
relacionado con los materiales evaporíticos de las
Acuífero Detrítico de Gallocanta.
Se trata de materiales terciarias y cuaternarios que rellenan una cubeta alargada de
dirección NO-SE interrumpida por algunos relieves residuales mesozoicos. La extensión de esta
cubeta es de 225 km2 y su espesor medio es de unos 110 m. Esta formado por conglomerados y
lutitas. Los depósitos perilagunares son mas finos. El sustrato de este acuífero lo constituyen
materiales triásicos, jurásicos y cretácicos.
En la zona del entorno de la laguna, la potencia de este acuífero es mínima,
aproximadamente unos 4 a 5 metros. Los bombeos de ensayo realizados junto a la laguna, dan
unos espesores saturados de 2 a 3 m. El coeficiente de almacenamiento sería el 4% y las
reservas serían del orden de 3 hm 3 .
En este acuífero se han inventariado unos 100 puntos de agua, especialmente pozos que
se sitúan en los municipios de Tornos, Gallocanta y Bello, es decir en las proximidades de la
En este acuífero existe una clara evolución geoquímica, las aguas bicarbonatadas-cálcicas
y cálcico-magnésicas se disponen en las zonas de borde del acuífero detrítico, donde el agua
procede o bien de cuaternarios de piedemonte (al NE) o bien del acuífero calizo (al SO).
Figura 9.- Acuífero Detrítico de Gallocanta
En la zona central las aguas son bicarbonatadas-sulfatadas-cálcicas y bicarbonatadassulfatado-cloruradas
calcio-magnésicas. Ello se corresponde con un mayor tiempo de residencia
en el entorno de la laguna, cuyos materiales de depósito son ricos en sulfatos. El contenido de
sulfatos y cloruros aumenta en las proximidades de la laguna.
Se han detectado elevadas concentraciones de nitratos y nitritos (por encima de niveles
legales de potabilidad, establecidos en 50 mg/l) en la mayoría de los puntos del acuífero sobre
todo en los utilizados para el abastecimiento de Bello, Tornos y Cubel. Estas altas
concentraciones asociadas a un alto contenido de K + sugieren una contaminación relacionada
con el uso masivo de abonos agrícolas.
Asimismo si han reconocido altos contenidos de nitritos entre Tornos y Bello en relación
con aguas residuales. Existen también puntos con altos contenidos en cloruros de sodio,
relacionados con la existencia de explotaciones ganaderas en las proximidades de Bello.
Los vertidos de los núcleos de población se realizan directamente sobre el terreno, sin
existir procesos de depuraciones en la mayoría de los municipios (excepto Tornos).
Varias localidades (Cubel, Santed, Used y Las Cuerlas) disponen de fosas sépticas Estos
vertidos aportan una cantidad significativa de coliformes que generan una cierta contaminación
orgánica en el entorno de la laguna.
Teniendo en cuenta que el acuífero detrítico de Gallocanta es un acuífero libre y de
elevada transmisividad, se puede afirmar que presenta un alto grado de vulnerabilidad a la
Funcionamiento Hidrogeológico del conjunto
El conjunto del sistema funciona como en embalse regulador, que recibe la infiltración
del agua de lluvia y la escorrentía de las sierras que lo enmarcan, alimentando a la laguna de
Gallocanta. El esquema que se acompaña es un balance de agua de la cuenca endorreica (ver fig.
10), los balances cierran perfectamente, pero existen grandes dudas sobre la validez de las
cifras. La incertidumbre en determinadas variables es extremadamente grande, por lo que
creemos que el esquema debe servir ante todo como ejemplo de relaciones entre acuíferos,
laguna, explotación de pozos....
La laguna de Gallocanta recibe el agua del flujo subterráneo procedente de los acuíferos,
así como el agua de lluvia que cae sobre ella, además del agua que ocasionalmente aportan los
barrancos. Las perdidas de agua en el vaso de la laguna son exclusivamente por evaporación.
Destacar que debido a su topografía, extremadamente plana, simplemente el balance de agua
(evaporación-precipitación) hace que la laguna esté totalmente inundada o totalmente seca. De
hecho en invierno con una evaporación mínima, aún sin precipitaciones la laguna adquiere una
Figura 10.- Balance de agua de la Laguna de Gallocanta
extensa lámina de agua, por el contrario en la época estival, la evaporación es tan intensa (más
de 10 mm/día) que prácticamente es imposible la permanencia de esa lámina de agua. Además
el volumen de agua subterránea que se extrae mediante pozos es pequeña, pero su efecto sobre
la lámina de agua en la laguna puede ser crítico, teniendo en cuenta que las extracciones se
realizan en el borde de la laguna. De hecho puede verse en la figura 11 como desde que se
extraen aguas subterráneas la laguna no responde igual ante la llegada de años húmedos.
Figura 11.- Volumen de agua de lluvia, extracciones y profundidad de la Laguna de Gallocanta
Ambientes sedimentarios de la Laguna de Gallocanta
La forma de la laguna es alargada, con una longitud máxima de 7,5 km y una anchura
media de unos 2,85 km, y en ella se identifican tres sectores bien diferenciados
morfológicamente. En el extremo más noroccidental se sitúa "El Lagunazo de Gallocanta", de
forma subcircular y 1,2 km de diámetro, está separado del resto de la laguna por una barra
conglomerática denominada localmente Los Picos, la cual ha sido posiblemente cortada por la
acción humana para comunicar los diferentes sectores de la laguna. "El Lagunazo grande o
central" es el cuerpo principal de la laguna. Presenta forma alargada de dirección NO-SE con
unos 5 km de longitud y 3 km de anchura. En el sector Suroccidental se localizan "Los ojos de
la laguna", conjunto de manantiales alrededor de los cuales se desarrolla una amplia zona
palustre funcional, en buena parte afectada por la acción antrópica. Por último, en el extremo
oriental se sitúan "Los lagunazos de Tornos" que integran un área palustre funcional de unos 2,9
km de longitud y 4,2 km de anchura.
La distribución de facies sedimentarias ha sido esquematizada en la figura 12. A partir de
los datos obtenidos se han diferenciados tres dominios: lacustre central, lacustre marginal y
palustre. El paso entre el sector central y el marginal puede ser neto, o realizarse a través de una
zona transicional que hemos denominado lacustre marginal/central.
Figura 12.- Distribución de ambientes sedimentarios en la Laguna de Gallocanta
El subambiente lacustre central está localizado hacia el NW y SE de los Picos de la
laguna. Ocupa un área de 1x0.5 Km en el Lagunazo y 4.2x1.2 Km en la Laguna grande. Este
sector está caracterizado por el desarrollo de barros negros y el crecimiento de cristales de halita
recubiertos por mallas estromatolíticas. Los barros negros presentan una composición dada por
calcita, dolomita, aragonito, yeso, anhidrita, halitas y blohedita, además de bajas proporciones
en cuarzo y minerales de las arcillas.
El subambiente lacustre marginal ocupa una extensa área y en el ha sido diferenciado un
sector interno y otro externo. El sector más interno ocupa una banda de 0.2 a 0.5 km que se
extiende alrededor del sector central. Presenta muy bajo gradiente topográfico y muestra una
clara asimetría, estando mejor desarrollado en el margen sur de la laguna que en el sector norte.
Los sedimentos característicos consisten en lutitas marrones y margas grises que presentan
oxidaciones y frecuentes bioturbaciones. Es habitual la presencia de costras laminadas
estromatolíticas que atrapan cristales de sales. La composición mineralógica viene dada por
calcita, dolomita, cuarzo minerales de las arcillas y en menor medida halita. En los centímetros
más superficiales hay también yeso, aragonito y hexahedrita. El sector más externo representa
una zona discontinua identificada a lo largo del borde de la laguna. Es un sector cubierto por
Salicornia ramosissima asociada a algas mats. Los sedimentos son lutitas de color marrón y
areniscas de grano grueso entre las que aparecen cantos conglomeráticos de cuarcita.
El subambiente palustres se sitúa alrededor de la laguna y aparece dominantemente
concentrado en dos zonas. La primera de ellas se localiza en el sector NW de la laguna y está
caracterizada por la presencia de manantiales (los ojos de la laguna). La segunda se sitúa al SE y
ocupa el sector denominado Los lagunazos de Tornos. Los sedimentos de este subambiente
están caracterizados por lutitas grises con abundantes gasterópodos, y sobre las que se desarrolla
una densa vegetación de juncos y carrizos. La mayor parte de este subambiente está modificado
por la acción antrópica y son actualmente campos de cultivo.
PARADA 3.-: Panorámica de la Laguna de la Zaida. Esta laguna comprende todos los cauces
procedentes de la sierra de Santa Cruz, formada por materiales paleozoicos, que vierten a esta
laguna. La laguna de la Zaida permanece seca de 2 a 3 años seguidos, con el objeto de
cultivarla, y un año con agua. Para ello el hombre realizó un sistema regulador de inundación de
la laguna, que retiene el agua de los barrancos que vierten en ella, en La Parada y La Retuerta.
La represa formada por la Parada encharca la depresión más inmediata a la compuerta y a
continuación la de la Retuerta, desde donde rebosa a la acequia Nueva- Arroyo de la Cañada,
que finalmente vierte el agua a la Laguna de Gallocanta.
PARADA 4.- Panorámica de la Laguna de Gallocanta y observación en detalle de los depósitos
lacustres marginales externos. Se visitará la estación meteorológica situada en los “Picos de la
Laguna” la cual recoge principalmente medidas de precipitaciones, temperatura del aire y del
suelo, velocidad y dirección del viento, evaporación y humedad.
Recorrido de la zona palustre de los Aguanares y observación de los dos manantiales de los que
se abastece el pueblo.
SEGUNDO DÍA DE CAMPO: EL SISTEMA ACUÍFERO DE ALFAMEN
El sistema acuífero de Alfamén es un complejo conjunto de acuíferos detríticos y
carbonatados que ha dado lugar a la mayor y más rentable transformación de secano a regadío
con aguas subterráneas de todo Aragón, y posiblemente de la cuenca del Ebro. Este complejo
sistema de acuíferos recibe su nombre de la localidad situada en el centro del mismo, que es
además la que de un modo más evidente ha experimentado el paso de un territorio seco, no
productivo, a una zona regable de frutales, hortalizas...
Actualmente se extraen cerca de 50 hm3/año de aguas subterráneas, los regadíos en la
zona suman unas 15000 ha, de las que 7000 son exclusivamente con aguas subterráneas, 5000
se riegan con aguas del río Jalón derivadas mediante acequias, y unas 3000 ha son de regadío
En la zona continúan las transformaciones en regadío, aunque parece evidente un
descenso de los niveles de agua en los acuíferos y comienza a considerarse la existencia de
sobreexplotación, al menos en zona localizadas del sistema acuífero.
Figura 13.- Mapa geológico de la zona de Alfamén, y situación de los cortes.
Unidades acuíferas y su relación
La figura 13 corresponde a un mapa geológico de la zona, como puede verse
predominan los materiales cuaternarios que constituyen un extenso glacis, que desciende desde
las sierras paleozoicas situadas al sur, hasta los relieves estructurales que al norte forma las
calizas de La Muela (depósitos lacustres del Mioceno con las que se colmata la cuenca terciaria
del Ebro). En los limites de las sierras aparecen pequeños afloramiento de materiales
carbonatados mesozoicos, al igual que hacia los ríos Jalón y Huerva.
Los ríos Jalón y Huerva constituyen los límites hidráulicos del sistema acuífero, pero el
plano de la figura 13 es poco expresivo de lo que este sistema acuífero encierra. Los datos de
más de 1000 sondeos y pozos han permitido conocer los acuíferos y su relación, así la figura 14
es un corte E-W del Sistema Acuífero, donde puede verse el acuífero carbonatado mesozoico
(calizas del Jurásico especialmente) y los acuíferos detríticos que constituyen las unidades
Figura 14.- Sección hidrogeológica este-oeste (corte 1)
Siguiendo la misma figura, podemos identificar una unidad detrítica superior, que da
lugar a un acuífero libre, aparece marcada con la letra Q (aunque se sabe que es pliocuaternaria).
Por debajo existe, una formación acuitarda (T/B1), que corresponde a materiales
margosos, que siguiendo la denominación de los sondistas se cita como “marga blanca”. Por
debajo, se encuentra el acuífero terciario que principalmente se explota, es una alternancia de
gravas con cantos y niveles de lutita (arcilla) de edad Mioceno que llega a tener más de 400
metros de espesor, se trata de un acuífero multicapa.
Los caudales que se obtienen en los sondeos, son a veces muy importantes, siendo
frecuentes valores superiores a los 80 l/s, con descensos de 60 a 100 (el acuífero es confinado).
Cuando se explota el acuífero superior (Q), si el espesor saturado es importante, más de 50 m.,
se pueden obtener caudales superiores a los 50 l/s, con descensos de poco más de 20 m.
Destacar que entre el acuífero detrítico terciario (T/B1) y el carbonatado mesozoico existe
un acuitardo formado por lutitas de edad Cretácico (Weald), este acuitardo es efectivo al este de
la carretera Alfamén-Almonacid, independizando ambos acuíferos, al oeste de esa carretera el
acuitardo ha desaparecido o por su reducido espesor no separa ambos acuíferos. Este hecho
queda manifiesto en los niveles piezométricos de cada acuífero.
Los cortes 2, 3 y 4 de las figuras 15, 16 y 17 completan la imagen tridimensional de estas
unidades acuíferas y la relación que existe entre ellas.
Figura 15.- Sección hidrogeológica norte-sur (corte2)
El corte 2 es representativo del lugar de la parada, destacando la notable diferencia que
existen en los niveles de agua de los distintos acuíferos. El corte 3 es representativo de la
situación junto a la localidad de Alfamén, si bien al este de la carretera Almonacid-Alfamén,
destacar que el acuífero terciario tiene su nivel por encima del acuífero cuaternario (hasta
tiempos recientes era surgente en todos los sondeos, incluso de forma natural sus aguas
atravesaban el acuitardo y llegaban hasta la superficie, dando lugar a zonas húmedas como las
situadas junto a la ermita de la Virgen de las Lagunas.
Figura 16.- Sección hidrogeológica norte-sur (corte 3).
Finalmente en el corte 4 (ver fig.17), el nivel del acuífero carbonatado es casi coincidente
con el del terciario, no existe el acuitardo (unidad cretácica en facies Weald)
Figura 17.- Sección hidrogeológica norte-sur (corte 4)
El elevado número de sondeos existentes, pero sobre todo los datos aportados por unos 20
piezómetros realizados por el Gobierno de Aragón en los que, siempre que es posible, se miden
los niveles por separado de cada unos de los acuíferos (piezómetros en racimo), ha permitido la
elaboración de mapas de isopiezas específicos de cada uno de los acuíferos (planos 1, 2 y 3 de
las fig. 18, 19 y 20).
Figura 18.- Isopiezas del Acuífero detrítico superior (plano 1)
El plano 1 (ver fig. 18) corresponde al mapa de isopiezas del acuífero detrítico superior, el
cuaternario, como puede verse este acuífero tiene una extensión superficial más restringida que
los inferiores, el flujo del agua es claramente hacia el río Jalón. Se acompañan la evolución de
los niveles de agua en el piezómetro P-14 situado junto a la localidad de Alfamén (el nivel se
mantiene entre 435-440 m.s.n.m.).
El Plano 2 (fig 19) muestra el mapa de isopiezas del acuífero detrítico inferior
(Mioceno), como puede verse el flujo se dirige también hacia el río Jalón, destacando el fuerte
desnivel piezométrico existente al oeste de Alfamén. La cota de agua en el P-14 (piezómetro
anterior) es inicialmente de 450 m.s.n.m. (condiciones surgentes), pero como puede verse los
bombeos en los últimos quince años le han hecho descender por debajo de los 420m, las
variaciones estacionales relacionadas con los bombeos son muy evidentes.
Figura 19.- Isopiezas del Acuífero detrítico inferior (plano 2)
Figura 20.-Mapa de isopiezas del acuífero carbonatado mesozoico (plano 3).
El Plano 3 (fig. 20) muestra el mapa de isopiezas del acuífero carbonatado, como puede
verse los sondeos que lo alcanzan son escasos, pero son suficientes para realizar un mapa que
muestra el drenaje que el río Jalón realiza en toda la unidad acuífera. Destacar que en la zona de
Alfamén la cota del agua en este acuífero se sitúa en unos 380 m.s.n.m., es decir más de 50 m
por debajo de los niveles de los acuíferos detríticos que se encuentran estratigráficamente por
PARADA 1.-Carretera Cariñena a Longares. El objeto de esta parada es observar la
topografía de la zona y explicar las distintas unidades acuíferas existentes y su relación.
PARADA 2.-Después de un recorrido por diferentes explotaciones de regadío, donde es
posible observar diferentes sistemas de riego (goteo, aspersión, pívot...) se pretende la
observación de un piezómetro en racimo y las bombas de elevación de una explotación
cooperativa (Sociedad Agraria de Transformación).
Los manantiales de Pontil como ejemplo del drenaje subterráneo de la Cordillera Ibérica
en la Depresión Terciaria del Ebro
El acuífero carbonatado mesozoico citado anteriormente constituye un extenso acuífero
que ocupa toda la vertiente norte de la Rama Aragonesa de la Cordillera Ibérica, por este
acuífero carbonatado circula el agua subterránea hasta el contacto con los materiales poco
permeables de la Depresión Terciaria del Ebro (margas y yesos), donde surge dando lugar a una
decena de grandes manantiales que suman un caudal de más de 5000 l/s. El mapa de isopiezas
de la figura 21 muestra la gran extensión de este acuífero carbonatado, gran parte de él cubierto
por materiales del terciario, y como el flujo del agua subterránea se dirige hacia unos pocos
grandes manantiales. El acuífero más importante corresponde a las carniolas del Lías (Jurásico
inferior), por su disposición estratigráfica inmediatamente por encima de una unidad
impermeable (arcillas y yesos del Keuper) constituye el nivel de drenaje regional de toda la
Cordillera Ibérica en este sector, ese drenaje subterráneo es tan efectivo que algunos de los ríos
que descienden de la cordillera pierden totalmente sus aguas, las cuales aparecen en el mismo
río aguas abajo, o bien son transferidas a otros ríos como puede verse en la fig. 21.
Todos los manantiales de este acuífero tiene unos rasgos comunes que los identifican
como de flujo regional según la terminología de Toth.: caudal y composición química constante,
elevada mineralización (1500 mg/l), típica composición sulfatada cálcica, bajo contenido en
tritio, y una temperatura anormalmente alta, unos 25 ºC. Los manantiales más importantes se
sitúan en relación con falla una falla inversa que limita la Cordillera Ibérica con la Depresión
Terciaria del Ebro (falla nordibérica), esta falla sólo es aflorante en La Rioja, mientras que en
Aragón está fosilizada por materiales terciarios del Mioceno. Otros manantiales se sitúan en el
contacto de los materiales carbonatados con las arcillas y yesos del Keuper que forman el
núcleo de estructuras anticlinales.
Los manantiales de Pontil se sitúan en relación con la citada falla nordibérica. La Figura
22 muestra un corte WSW-ENE que sería aproximadamente coincidente con la traza del río
Jalón. Destacar la presencia de anhidrita, su lavado por las aguas subterráneas a lo largo del
tiempo dar lugar a las brechas carbonatadas del Lías. Estas brechas son un acuífero excepcional
por su elevada porosidad y permeabilidad, de hecho los sondeos realizados dan caudales
superiores a los 100 l/s con apenas 5 metros de descenso.
Figura 21.- Mapa de isopiezas de los acuíferos carbonatados ibéricos en su
vertiente hacia el Ebro y ubicación de la zona estudiada.
PARADA 3.-Manantiales de Ojos de Pontil: conjunto de pequeñas depresiones por las
que surgen flujos ascendentes de agua que suman casi 500 l/s. Su composición es sulfatada
cálcica y su mineralización de 1400 mg/l, la temperatura de emergencia es de 23 ºC.
Los ojos y su zona húmeda asociada ocupaban hace unas décadas más de 12 ha,
conociéndose el lugar con el nombre de “los prados”. Hasta la reciente intervención del
Ayuntamiento de Rueda de Jalón parte de los terrenos se utilizaban como escombrera ilegal,
también deterioró mucho el humedal el intento de instalar una piscifactoría de anguilas
aprovechando el agua caliente. Actualmente es una zona protegida de gran valor ambiental y
científico, donde aún es posible ver manifestaciones de flujos ascendentes de agua como son los
“volcanes de arena”.
(Después de esta parada, y tras la comida se inicia el recorrido hacia el Pirineo. Según la
disponibilidad de tiempo se realizará alguna parada para explicar la estructura general de la
PARADA 4.-Cuenca y abanico aluvial del barranco de Arás en Biescas (Huesca). Se
realiza una parada en el abanico aluvial de este barranco donde el 7 de agosto de 1996 tuvo
lugar una avenida torrencial que arrasó un camping, produciendo 87 muertos y daños estimados
en más de 8000 millones de pesetas. Este desastre ha sido el mayor ocurrido en España, en
términos de vidas humanas, en los últimos 25 años.
Se entrega una publicación de F. Gutiérrez et al. (1998) en la revista de la Soc. Geológica
TERCER DÍA DE CAMPO: LAS AGUAS TERMALES DE PANTICOSA
El balneario de Panticosa se localiza en la denominada zona Axial Pirenaica, se encuentra
por tanto en el núcleo de la citada cordillera donde predominan los materiales graníticos,
rodeados por pizarras y calizas fuertemente metamorfizadas.
Figura 22.- Corte hidrogeológico
Panticosa es un centro balneario cuyo mayor auge se produjo a finales del siglo XIX y
primeras décadas del XX, fechas a las que corresponden la mayor parte de los edificios actuales.
Existen indicios de uso del agua termal en la época de los romanos, una excavación en la fuente
de Tiberio, encontró monedas de la época. Actualmente toda la zona está en reconversión, en
invierno es lugar de práctica de sky nórdico y paseo de raquetas, además de lugar de arranque de
numerosas excursiones de alta montaña. De hecho está rodeado de montañas que superan los
3100 m de altitud. El balneario se encuentra a una cota de 1600 m.
La figura 23 muestra la situación de los principales manantiales termales, como puede
verse la mayoría reciben nombre relativos a la supuesta capacidad curativa o paliativa
reconocida, se trata de aguas minero-medicinales. Hay que destacar que la pretensión de
aumentar los caudales en determinados manantiales mediante pequeños taladros horizontales,
ha provocado la desaparición de algunos de ellos y/o la comunicación de aguas de diferente
naturaleza. Este es un hecho grave ya que el carácter minero-medicinal requiere, además de un
historial clínico, la constancia de la composición físico-química de las aguas.
La tabla 1 es un resumen de los datos existentes de todos los manantiales y sondeos:
Temperatura Q (l/s)
Manantial Tiberio 46,7 0,5-4
Manantial Escalar 21,0 0,09
Manantial de la Laguna 23,8 0,15
Fuente San Agustín 27,0 0
Fuente Estomago 31,0 0,15
Fuente del Hígado 25,0 Seca
Sondeo El Carmen 39,5 1,8
Sondeo San Agustín 27,0 0,1
Sondeo Fuente del Hígado 21,0 ?
Tabla 1.- Datos de Temperatura y Caudal de los sondeos
T(º) sec/vol Q(l/s) Medición
Fuente del Estómago 25,7 2,45 0,204
Taladro Fuente San Agustín 29 5,75 0,087 volumétrico regulado
Taladro del Hígado 23,3 7 0,071 volumétrico regulado
Fuente del Carmen* 11,6 17,25 0,029 volumétrico
Fuente de la Laguna 24,7 3 0,166 volumétrico
Fuente del Escalar 20,7 7 0,071 volumétrico
Datos comparativos (DGA,
Fuente del Estómago 28,5 0,23
Taladro Fuente San Agustín 27,2 0,11
Taladro del Hígado 21,5
Fuente de la Laguna 23,8 0,126
Fuente del Escalar 19,6 0,05
Tabla 2.- Datos recogidos durante 1998
Durante el año 1998 se realizó un trabajo de campo con mediciones en los diferentes
puntos, obteniendo los siguientes resultados (ver tabla 2).
Finalmente la tabla 3 muestra las características físico-químicas de los principales
manantiales, como puede observarse se trata de aguas de muy baja mineralización (unos 100
mg/l), valores elevados de pH, sodio como catión dominante y ausencia de un anión
predominante. Destacar el elevado contenido en sílice, y la presencia de desprendimientos de
H 2 S en condiciones de surgencia. En esta tabla se acompañan también datos de las
características del agua del lago, hay que destacar que la mezcla de las aguas termales con las
aguas superficiales frías se produce en casi todos los manantiales.
l /l mg/l l /l
Conductividad a 20ºC
S/cm Conductividad a 20ºC
pH 7,69 pH 7,43
3 SiO2 3,03
0 0,40 36,34 Cloruros 5,70 0,16 27,91
Sulfatos 4,10 0,09 7,66 Sulfatos 4,20 0,09 15,07
0 0,60 54,53 Bicarbonatos
0 0,30 52,34
Carbonatos 0,00 0,00 0,00 Carbonatos 0,00 0,00 0,00
Nitratos 1,00 0,02 1,47 Nitratos 1,70 0,03 4,67
0 0,49 52,43 Sodio 2,30 0,10 18,89
Magnesio 1,90 0,16 16,98 Magnesio 1,70 0,14 26,78
Calcio 5,60 0,28 29,72 Calcio 5,60 0,28 53,55
Potasio 0,30 0,01 0,86 Potasio 0,20 0,00 0,78
Conductividad a 20ºC
S/cm Conductividad a 20ºC
pH 8,30 pH 8,72
0 1,04 33,90 Cloruros
0 0,58 35,71
0 1,39 45,29 Sulfatos
0 0,44 27,31
0 0,46 15,00 Bicarbonatos
0 0,40 24,63
Carbonatos 4,80 0,16 5,22 Carbonatos 5,40 0,18 11,08
Nitratos 1,10 0,02 0,59 Nitratos 1,30 0,02 1,27
0 2,09 74,33 Sodio
0 1,16 76,54
Magnesio 4,90 0,40 14,21 Magnesio 1,70 0,14 9,22
Calcio 6,00 0,30 10,66 Calcio 4,00 0,20 13,17
Potasio 0,90 0,02 0,80 Potasio 0,60 0,02 1,07
Conductividad a 20ºC S/cm Conductividad a 20ºC S/cm
pH 9,11 pH 9,48
0 0,38 24,63 Cloruros
0 0,50 27,08
0 0,32 20,92 Sulfatos
0 0,43 23,46
0 0,38 24,63 Bicarbonatos
0 0,38 20,58
0 0,44 28,52 Carbonatos
0 0,52 28,17
Nitratos 1,30 0,02 1,31 Nitratos 0,80 0,01 0,72
0 0,78 54,68 Sodio
0 1,34 80,76
Magnesio 4,90 0,40 27,88 Magnesio 1,70 0,14 8,46
Calcio 4,80 0,24 16,73 Calcio 3,20 0,16 9,67
Potasio 0,40 0,01 0,71 Potasio 0,70 0,02 1,11
Tabla 3.- Características físico-químicas de los principales manantiales
La figura 24 es un modelo conceptual del flujo de agua subterránea en el macizo
granítico, en esencia la zona de recarga se sitúa por encima de los 2000 m.s.n.m., infiltrándose
el agua según un flujo vertical descendente. En profundidad el agua aumenta su temperatura en
función de un gradiente geotérmico normal (1ºC de aumento por cada 33 m), el aumento de
temperatura del agua provoca una disminución de su densidad por lo que se produce un flujo
vertical ascendente. La zona de descarga se localiza en la zona granítica de menor cota (zona del
Figura 24..- Modelo conceptual del flujo de agua subterránea en el macizo Granítico.
Destacar que en terrenos no volcánicos, los manantiales termales de mayor temperatura se
localiza siempre en granitos (hasta 70-80 ºC, en Cataluña y en Galicia), el motivo es que estos
terrenos mantienen durante miles de metros de profundidad las mismas características
hidrogeológicas (medios fisurados), incluso la disminución de la permeabilidad en profundidad
se ve compensado por la disminución de la viscosidad al aumentar la temperatura.
En la zona de descarga existe mezcla con aguas frías que se encuentran en los potentes
derrubios existentes, toda la zona es de riesgo de avalanchas, especialmente aludes. Un hecho a
destacar es que las aguas frías del lago (de elevada densidad), condicionan que el flujo termal
disperso se dirija hacia el entorno del mismo, provocando así una cierta concentración.
PARADA 1.-En Panticosa se realizará un recorrido por los principales manantiales
PARADA 2.-Vista general del Sinclinal de Jaca y del campo de gas del Serrablo
PARADA 3.-Si es posible visita al manantial de Tiermas en el embalse de Yesa. (Sólo
visitable si el citado embalse tiene su nivel de agua por debajo de la cota del manantial)
Figura 23.- Situación de los manantiales del área de Panticosa
La figura 25 corresponde a un mapa geológico simplificado del Sinclinal de Jaca, los
cortes 1 y 2 corresponden a dos transversales de dicho sinclinorio. Como puede observarse en
las figuras citadas, esta gran cuenca sinclinal tiene como sustratos a materiales carbonatados
cretácicos y eocenos, y esta rellena de materiales turbidíticos también eocenos que tienen varios
miles de metros de potencia. El campo gasístico se desarrolla en estas turbiditas, siendo la roca
almacén unas capas calizas intercaladas en la serie de lutitas y areniscas (flysh eoceno). Estas
capas calizas se interpretan como “olistostemas”, que serían trozos de plataforma deslizadas por
el talud continental.
Figura 25.- Mapa geológico simplificado del Sinclinal de Jaca. Cortes 1 y 2
corresponden a dos transversales de dicho sinclinorio
La figura 26 corresponde a uno de los sondeos en explotación del campo de gas del
Serrablo, como se indica en el tríptico que se acompaña, actualmente el yacimiento de gas se
utiliza como almacén subterráneo, se inyecta gas durante el verano y se extrae durante el
Figura 26.- Sondeo en explotación del Campo de Gas del Serrablo
Un hecho a destacar es que los sondeos existentes tienen aguas subterráneas termales (con
valores superiores a los 100ºC), de composición clorurada sódica, tal y como puede verse en la
Carbonatos 0 0
Bicarbonatos 486 8,1
Cloruros 9926 280
Sulfatos 620 12,91
Calcio 254 12,7
Magnesio 77 6,3
Sodio 6450 280,43
Potasio 65 1,66
Hierro 0,5 0,01
Tabla 4.- Composición del agua subterránea en el sondeo
El manantial de Tiermas se sitúan en la terminación occidental del sinclinal de Jaca, existe
incertidumbre sobre el origen de sus aguas, pero estimamos que corresponde a la descarga de las
formaciones carbonatadas que constituyen el sustrato del citado sinclinal. El caudal de este
manantial supera los 200 l/s y su temperatura es de unos 39 ºC, se trata por tanto de un auténtico
río de agua termal. La composición de estas aguas es clorurada sódica, tal y como puede verse
en la siguiente tabla 5:
SONDEO TIERMAS mg/l meq/l %meq/l
Conductividad a 20ºC 6240 S/cm
Cloruros 1907,20 53,79 74,09
Sulfatos 677,50 14,10 19,43
Bicarbonatos 283,10 4,64 6,39
Carbonatos 0,00 0,00 0,00
Nitratos 4,10 0,07 0,09
Sodio 1202,40 52,30 74,69
Magnesio 92,40 7,60 10,85
Calcio 192,40 9,60 13,71
Potasio 20,60 0,53 0,75
Tabla 5.- Composición del agua en el sondo de Tiermas
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 67-71
FIELDTRIP TO THE UPPER LOZOYA VALLEY AND
PEÑALARA HANGING GLACIER CIRQUE
CENTENO, J.D. 1 and MOYA, M.E. 2
1 Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain).
2 Departament of Geology. Faculty of Sciences. Alcalá de Henares University.
El Paular basin
The Lozoya river feeded the first water supply
system of Madrid and most of present supply. The upper
Lozoya basin is coincident with the tectonic basin of "El
Paular", surrounded by the two branches of the Guadarrama
range: montes Carpetanos to the North and Cuerda Larga
(long line) to the South. During the Pleistocene, these
mountains developed many glaciers (mainly cirque glaciers
in their SE slopes) among them the Peñalara glacier.
Our fieldtrip will take us to the glacial hanging cirque
of Peñalara (showed ⊕ in the regional map) that was the
Figure 1. The Spanish Central range and the Guadarrrama mountains in the context of the Iberian peninsula
second Spanish natural site to be protected by law in 1930 and is nowadays subject to
increasing preservation measures. While the isolation of the valley -producing an slow rate of
development until today- explains the that few sources of contamination are to be found, present
growing of green tourism is producing an interesting conflict between development and
The Guadarrama range is an hercinian unit with gneiss's and granites (Precambrian to
Ordovician gneiss's and late Carboniferous granites), although some other rocks can be found
(metasediments, aplite and pegmatite dique, etc.).
The range is an morphostructural unit uplifted in the Alpine orogeny between the Duero
and Tajo Tertiary basins. Generally speaking, it is a simple morphostructure, with only a main
watershed and one summit line. However, within the range some small secondary basins are
well known, among them the "el Paular" o upper Lozoya basin. As many others, it is a WSW -
ENE fault defined basin traditionally interpreted as a graven but recently explained as a set of
low angle reverse faults.
Within the basin there are upper Cretaceous to Cuaternary sediment as remnants of a
former basin or filling of the present basin. These are the main aquifer units in the area as well
as the base for the few villages of the valley.
The climate in central Spain is mediterranean (dry and warm summer in contrast with a
cold and wetter winter), but many meteo processes do relate to the Central Range. As it extends
WSW-ENE an orographic barrier, rains in the Duero and Tajo basin depends on the storms path.
When storms travel South of the range rain is to be found in the Tajo while northern storms
bring rain to the Duero.
The double summit line of the upper Lozoya produces an increase of average rainfall in
the valley. So Navafría (North of montes Carpetanos) has a year average of 700 mm, Miraflores
(South of Cuerda Larga) 900 mm and Rascafría (within the upper Lozoya valley) 1350 mm.
This local increase in rainfall explains the Lozoya basin outflow and the presence of glaciers
during the Pleistocene.
Figure 2. Storm tracks anf rain in the Guadarrama
THE GLACIAL HISTORY OF PEÑALARA
Peñalara is the highest summit of the Guadarrama mountains (2430 m) and its glacial
cirque a main reference of the Spanish glacial geomorphology studies. Since the first works by
Obermaier and Carandell (1917) many scientists have studied its landforms, the glacial
processes and the ecology of the area. Until 1959, most models related the deposits and forms to
the classical alpine phases (Riss and Würm). Fränzle (1959) suggested that only Würm
processes had modelled the Spanish Central Range. Since then, most authors have accepted the
lack of evidence of any interphase evidence.
In 1983, Centeno prepared the first accurate mapping of the glaciers of the Guadarrama
mountains and Centeno et al.(1983) formulated a complete evolution model of the Peñalara
glacial cirque. Ultimately we modified this model (Acaso et al., 1998) identifying a rock glacier
(in the upper section) and three retreat moraines.
At the moment, all the recognized elements of the glacier have been drawn in figures 3
1. Maximum advance phase. Two parallel stabilization front moraines.
2. Advance and stabilization moraine phase. The biggest moraine complex including
prograding on phase 1 sediments and intra-moraine collapse lakes.
3. Retreat phase. Intra-moraine lake sediments.
4. Advance phase. Deformation till (folded lake sediments destroyed by restoration
5. Retreat and stabilization phase. Central moraine and disconnection of two cirques in
Peñalara and Dos Hermanas.
6. Progresive retreat. Three moraine arches in Peñalara cirque.
7. Last stabilization with depositional effects. Rock glacier in Dos Hermanas and rock
corridor in Peñalara.
Obermaier y Carandell, 1917 Centeno, Pedraza y Ortega,
Acaso, Centeno y Pedraza,
Glacial volume ⇒
Figure 3. Classic and recent models of evolution of the glacier (after Acaso el al. 1998)
THE PUBLIC INTEREST ON PEÑALARA AREA
The scientific interest on Peñalara may be considered unusual and difficult to understand.
But some ideas can be put forward to explain it:
1. Its immediacy to Madrid made the area a favourite place for mountain sports and
geologist since the beginning of the XIX century.
2. The Peñalara glacial cirque is the only one to have several phases evidence in the
3. Its size and accessibility makes this cirque specially interesting for geology teaching
fieldtrips, a long tradition back to 1883 (Giner y Cossío, 1886) with a benchmark at the
declaration of Site of Natural Interest in 1930.
4. Since the middle 1979’s the area has suffered the struggle between developers (mainly
skiing resorts running since 1969 until 1999) and conservationists.
As a consequence of this general interest, the pressure on the physical and ecological
environment has been very high until the declaration of Natural Park in 1990, when control
have increased progressively.
Dos Hermanas summit (2380 m)
Peñalara summit (2430 m)
Recession Advance moraine
Figure 4. The main elements of the Peñalara glacier. Modified after Acaso et al., 1998. (modified after a watercolour and
pencil draw by E. Acaso)
At the moment, control of lake eutrophization and native species protection are the main
targets of the Natural Park staff. Erosion control have been set off in the Laguna de Peñalara
shore, but erosion problems may be very important in other points of the area.
OUR FIELDTRIP ITINERARY (Figure 5)
Travel North en route for the “El Paular” basin.
Observation of the basin general aspects and the glaciers setting.
Leave the bus at “Los Cotos” (1) mountain pass to walk headed for the maximum
advance moraines (2).
Then, walk along the glacier forms from the intramoraine “Laguna Chica” (3) to the
“Laguna Grande de Peñalara” (4).
Walk for a panorama at the Zabala refuge (5) and the rock glacier deposits (6).
Back to the bus.
Coffee at the skiing resort of Navacerrada.
If time and allows it, we’ll visit either the “Pepe Hernando” glacier (7) or the “Claveles”
and “Los Pájaros” (8 and 9)
We’ll trek through rough mountain terrain. Boots and warm clothing are indispensable.
Weather changes might be dramatic so the excursion will be always subject to changes.
Peñalara, 2430 m
summit, 2380 m
Figure 5. Topographic map and fieldtrip
0 500 m
ACASO, E.; CENTENO, J.D. y PEDRAZA, J. (1998): Nuevas aportaciones al modelo
evolutivo del glaciar de Peñalara (Sistema Central Español). Aportaciones a la V reunión
nacional de Geomorfología, Granada: 691-695.
CENTENO, J.D. (1983) Sintesis y evolución geomorfológica de la sierra de Guadarrama, Tesis
de Licenciatura, Inedita
CENTENO, J.D; PEDRAZA, J. DE y ORTEGA, L.I. (1983): Estudio geomorfológico,
clasificación del relieve de la sierra de Guadarrama y nuevas aportaciones sobre su morfología
glaciar. Bol. R. Soc. Española Hist. Nat. (Geol) 81 (3-4):153-171.
FRÄNZLE, O. (1959): Glaziale und periglaziale Formbildung im ostlichen Kastilischen
Scheidegebirge (Zentralspanien). Bonner Geographische Abdanlungen, Bonn, 80 pp.
[Traducción española de J. Sagredo en Est. Geogr. 39, 151: 203-231 y 152: 363-419 (1978)]
GINER, F. y COSSÍO, L. (1886) Excursión durante las vacaciones de verano de 1883, Boletín
de la Institución Libre de Enseñanza, nº 237: 384, nº 239: 31-32, nº 240: 95-96, nº 241: 111-
112, nº 242: 127-128, nº 243: 143-144, nº 159-160.
OBERMAIER, H. y CARANDELL, J. (1917): Los glaciares cuaternarios de la sierra de
Guadarrama. Trab. Del Mus. Nac. de Cienc. Nat. Serie Geol., nº 19, Madrid, 95 pp.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 73-77
EVALUATION OF THE RUNOFF EROSION IN THE DRAINAGE
BASIN OF THE PUENTE ALTA RESERVOIR (SEGOVIA)
JOSÉ MARÍA BODOQUE DEL POZO
Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
Runoff erosion in the Puente Alta watershed has been evaluated by means of both
direct and indirect (or empirical) methods. Regarding the first group, the quantification of the
reservoir's sediments, accumulated over forty years since the dam was built in 1955, has been
the basis for the evaluation. This information has subsequently been used to validate the
empirical methods and to obtain the sediment yield; in this latter case, a procedure that
combines the sediment delivery ratio (S.D.R.) concept and the Universal Soil Loss Equation
(USLE) has been carried out; besides, the Modified Universal Soil Loss Equation (MUSLE) has
been utilised. A Geographical Information System was built with each of the factors needed for
the evaluation of both equations; eventually they were implemented in the Idrisi 32 software.
The drainage basin of the Puente Alta reservoir is located in the north slope of the
Guadarrama Mountains (Spanish Central System, Segovia, Spain). It stores the water of the
Acebeda river, formerly used for the water supply of the city of Segovia. The watershed has an
area of twenty-two square kilometres, with the highest altitude at 2193 m and the lower at
When referring runoff erosion, we mean the evaluation of the soil loss in the rill-interrill
locations. Specifically, four procedures have been followed for the evaluation of the runoff
erosion, which can be classified either as direct or indirect.
Among the direct methods, the following were carried out: a) the assessment of the
sediment yield rate (Avendaño et al., 1994), by using the measurement of the sediments trapped
in the Puente Alta Reservoir during the period 1955-1995; b) the determination of erosion rates
from exposed roots, from the information supplied by the differential root’s rings growth pattern
when they are exposed by erosion (Carrara & Carroll, 1978), in order to check the data obtained
from the indirect methods.
The empirical models utilised have been the Universal Soil Loss Equation (USLE)
(Wischmeier & Smith, 1965) and the Modified Universal Soil Loss Equation (MUSLE)
(Williams & Berndt, 1977). A Geographic Information System, implemented in the Idrisi 32
software, was built with each of the factors needed for both evaluations.
The first equation has provided information about the gross erosion rates in t/ha/year
and it has allowed mapping those areas where the erosion processes act with different intensity;
besides, the sediment delivery ratio (S.D.R.) has been calculated (Avendaño et al., 1993). The
second equation has made possible to know the sediment yield in the watershed, on account of
the individual action of the rain amount with a volume of precipitation higher than the average
of the highest precipitation in twenty four hours, always referred to the 1955-1995 period; also,
a 'type' rainstorm defined by means of the average of all precipitation in twenty four hours in the
referred time period has been used in the assessment of sediment yield. Furthermore, its use has
allowed to locate and map the areas inside watershed that are source of sediments to the
reservoir (Figure 1).
Finally, it is important to emphasise that by means of the results obtained using the
direct methods, we have been able to validate the use of both experimental procedures, which
could be used in watersheds similar to that of Puente Alta.
EVALUATION OF THE RUNOFF
EROSION IN THE DRAINAGE BASIN OF
THE PUENTE ALTA RESERVOIR
(earth dam volume)
Source areas of
Figure 1. Methodology
By using the USLE equation, the obtained average gross erosion for the Puente Alta
watershed is 7/t/ha/year; however, its spatial distribution along the basin is heterogeneous, as a
function of the physiographic conditions, so that the specific results for different land use
classes are: dense forest, 0.4 t/ha/year; grazing land, 0.5 t/ha/year; medium dense forest, 7
t/ha/year; scrub land, 15 t/ha/year; negligible cover, 70 t/ha/year (Figure 2A, 2B)
The sediment yield’s results obtained for the Puente Alta watershed has been: 71
t/km 2 .year, by means of the measure of earth dam volume in Puente Alta Reservoir; 69
t/km 2 .year, using the Universal Soil Loss Equation (USLE) corrected with the sediment delivery
ratio (S.D.R.) coefficient. The deviation of the calculated sediment yield rates by means of an
indirect method is lower than 3 %, with regard the data obtained using the quantification of the
sediments trapped in the Puente Alta Reservoir.
Similarly, the development of the Modified Universal Soil Loss Equation (MUSLE) has
allowed to determine those areas inside the watershed which are potential sources of sediment to
the Puente Alta Reservoir. As well, it has been carried out an estimation of the total sediments
delivered to the reservoir, on account of every downpour during the period 1955-1995, whose
sum is 27,628 tons. This value let us define a sediment yield rate of 84 t/km 2 .year. (Figure 3).
Reservoir and Acebeda river
Medium dense forest
2200 4400 m
Figure2. A) Vegetation cover map; B) Average annual soil loss (t/ha/year) by gross erosion for the drainage basin
to the Puente Alta Reservoir.
Septiembre de 1965
Septiembre de 1972
Septiembre de 1976
Junio de 1977
Julio de 1970
Media de las máximas
2500 5000 m
Figure 3. Sediment delivery (in tons) in the five downpour with the highest precipitation volume during the period 1965-
1980; also, for a downpour defined by means of the average of the highest precipitation in twenty-four hours during that
ALLUÉ, M. (en prensa). Mapa Forestal de Segovia, Escala 1:50000. En: Mapa Forestal de
España (J. Sánchez de la Torre, ed.). Dirección General para la Conservación de la Naturaleza
(DGONA), Ministerio de Agricultura Pesca y Alimentación, Madrid.
AVENDAÑO, C.; CALVO, J.P.; COBO, R. & Sanz, M.E. (1993). “La modelización
matemática, ajuste y contraste del coeficiente de entrega de sedimentos a los embalses.
Aplicación al cálculo de la erosión de cuencas fluviales”. Centro de Estudios y Experimentación
de Obras Públicas (CEDEX), Madrid, 1, 210 pp.
AVENDAÑO, C.; CALVO, J.P.; COBO, R. & Sanz, M.E. (1994). “La modelización
matemática, ajuste y contraste del coeficiente de entrega de sedimentos a los embalses.
Aplicación al cálculo de la erosión de cuencas fluviales”. Centro de Estudios y Experimentación
de Obras Públicas (CEDEX), Madrid, 2, 40 pp.
CARRARA, P.E.; CARROLL, T.R., (1979). “The Determination of Erosion Rates from
Exposed Roots in the Piceance Basin, Colorado”. Earth Surface Processes, 4, 307-317 pp.
WILLIAMS, J.R. and BERNDT, H. D. (1977). “Sediment yield prediction based on watershed
hidrology”. Trans. ASAE 20: 1100-1104 pp.
WISCHMEIER, W.H. & SMITH, D.D. (1965). “Predicting rainfall - erosion losses from
cropland east of the Rocky Mountains”. Agr. Handbook No. 282, USDA, Washington, D.C.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 78-81
TERRAIN ANALYSIS IN COASTAL EROSION AND FLUVIAL
Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
Two main research areas are presented on this paper, related by the nexus of the terrain
analysis and the use of GIS.
In the coastal field, this analysis will take us to the establishment of erosion and
sedimentation areas that allow to infer morphodynamic patterns. On fluvial studies, terrain
analysis and GIS enables the calculation of morphometric parameters in order to interpret the
tectonic outline of the study area.
The main topic of my current research is the application of terrain analysis, taking as a
tool Terrain Digital Models (DTM) and GIS (Systems of Geographical Information), for the
handling and calculation of morphological data. They are used in two different ways and
environments, coastal erosion and terrain morphometrical anlysis.
Both research fields have been developed in collaboration with Dr. Guillermina Garzón,
and D. Jesús Page collaborated also in the coastal study.
The study area is located on the Cantabrian sea, between the towns of Comillas and San
Vicente de la Barquera (Cantabria). The beach of Oyambre (Jerra according to the geologic map
1:50.000) with 3 Km. of longitude is developed on the turbidites of the Eocene and Oligocene,
between two more resistant calcareous capes. The ria of the Rabia, constituted in fact by those
of La Rabia and of El Capitan drains at their oriental side. The protection of the W and NW
dominant winds develops an orientation NE in the beach, and a litoral drift towards the E, that
favors the evolution of a sandy spit advancing towards the ría outlet. The ría has a drainage
basin of about 40 Km 2 , but at the present time its solid discharge can be considered practically
absent. To it largely contributes the presence of two man-made dikes that close both creeks, and
that limit the tidal expansion almost in two thirds of their extension. The current feeding of
these Cantabrian beaches is basically autochthonous (Hernández Pacheco and Asensio Amor,
1966). In fact the beach of Oyambre is supplied in this oriental area of the cliff retreat, here
partly formed by a 70000 year-old risen beach (Garzón et al.,).
The following methodology for data collection and management has been repeated in a
systematic way for each campaign (Fig. 1). The head of the profiles, was located in stable points
to generate a profiles net as much perpendicular as possible to the beach and with an
homogeneous separation. 21 topographical profiles were surveyed along 6 field campaigns.
Digital terrain models where carried out from the data to determine the erosion-sedimentation
areas between each campaign and the volume of removed material. Field data interpolation was
performed with the method of Krigging by means of Surfer.
These terrain digital models were implemented in a GIS (Idrisi 32) program and the
areas of beach erosion-sedimentation were established. The removed sands volume was
calculated for each cell of our MDT in order to establish the flow patterns or morphodynamic
trends in the beach.
The interpretation of the obtained results in an annual scale, from April 2000 to March
2001, points out the existence of two differentiated areas (Fig. 2). The West area is dominated
y the erosion. It reaches it maximal under a rip-rap seawall built to protect the cliff erosion,
and in it surroundings, what reflects the negative interference that these human works cause on
the coastal dynamics. There is a net lost of material in this area, except for some patches of
scarce sedimentation conditioned by the detachments of cliff material.
Figure 1. Methodological outline
Transport occurs toward the East side of the beach, in which the sedimentation prevails.
Significant deposition occurs from the central part of the beach on. Some areas of erosion on the
East part of the beach could have their origin in the dismantlement of an incipient berm present
Figure 2. Erosion-sedimentation areas distribution in the period April 2000-March 2001
The conditioning factor for this accretion is possibly the material produced by the ría,
which would begin its coastal cycle again in this area. Inside the ría, the accumulation that takes
place in the sandbank, represents the deposit of the materials that the low tide is not able to
transport, due to the ría outlet constriction. This is the result of anthropic changes in the ría that
generates this dead space due to the fact that the energy for transportation is larger on the high
FLUVIAL MORPHOMETRY AND TERRAIN ANALYSIS
The study area is the oriental part of the Tajo Basin. It consists of an extensional
depression limited by important topographycal feature such as the Central System to the North,
Montes de Toledo to the South and Sierra of Altomira to the East. The basin is very much
conditioned by the tectonic of the area, as it is affected by a series of faults and cortical flexures
(Giner and de Vicente, 1995 and Sánchez Serrano, 2000), that condition rivers morphology and
disposition inside the basin, as well as their morphometric parameters (Garrote et al.,2000 and
Garrote and Garzón, 2001).
The followed research line is based in the calculation of land and fluvial morphometric
parameters in order to relate them to stresses affecting the study area, as well as the generated
structures. On one hand, calculation of fluvial morphometric parameters such as the gradient
index of the main fluvial courses of the basin, allowed us the characterization of the main
structures that affected them at basin scale. Figure 3 shows the results obtained after the gradient
index analysis (Garrote et al., 2000), according to the methodology of Hack() and Masana().
LINES OF SAME GRADIENT INDEX
HIGHTECTONIC ACTIVITY BOUNDS
Figure 3. Structural linecements interprete from the map of gradient index.
On a further step, some topographical parameters of the basin have been calculated, like
a roughness map, and from it the lineaments were interpreted, which mainly coincided in
direction with those calculated by means of the gradient index. Other new lineaments were
established, that, although not having a direct reflection on the fluvial courses, could be clearly
defined from the roughness map, as shown in figure 4. The followed methodology has ben
developed in Garrote and Garzon (2001) according the previous work of Sánchez Serrano et al.
(1998) or Sánchez Serrano (2000).
On comparing the figures 3 and 4, a similarity of results can be established, from which
we can confirm the utility of these studies in the determination of the lineaments and stress field
that condition the basin. It also can be stated, that not all the same lineaments can be interpreted
from both maps, but both methods are supplemented and in this way enables as to define in a
more precise way the group of structural lineaments and cortical flexures that control the
development of the basin of the Tajo River. It opens us a new way to calculate other
morphometric parameters that might contribute with new data and at the same time supplement
those already established.
Figure 4. Principal structural lineaments as defined from the roughness map
GARZÓN, G., ALONSO, A., TORRES, T. y LLAMAS, J. (1995). “Edad de las playas colgadas
y de las turberas de Oyambre y Merón (Cantabria)”.Geogaceta. 20 (2). 498-501 pp.
GARROTE, J., FERNÁNDEZ, P. y GARZÓN, G. (2000). “Parámetros morfométricos en la red
de drenaje y sus implicaciones estructurales en la cuenca del Tajo”. VI Congreso
GARROTE, J. y GARZÓN, G. (2001). “Respuesta morfológica a los esfuerzos recientes en el
sector oriental de la depresión del Tajo”. V Iberian Quaternary Meeting. Lisboa.
GINER, J.L. y DE VICENTE, G. (1995). “Crisis tectónicas recientes en el sector central de la
cuenca de Madrid”. In Reconstrucción de paleoambientes y cambios climáticos durante el
Cuaternario. 141-162 pp.
HACK, J.T. (1973). “Stream-profile analysis and stream-gradient index”. Jour. Research U.S.
Geol. Survey. Vol. 1 Num. 4. 421-429 pp.
HERNÁNDEZ-PACHECO, F. y ASENSIO, I. (1966). “Fisiografía y sedimentología de la playa
y ría de San Vicente de la Barquera (Santander)”. Estudios Geológicos. 22. 1-23 pp.
MASANA, E. (1994). “El análisis de la red fluvial en el estudio de la neotectónica en las
cadenas costeras catalanas”. Geomorfología en España. 29-41 pp.
SÁNCHEZ SERRANO, F., TEJERO, R. y BERGAMIN, J.F. (1998). “Análisis de la
variabilidad del relieve a partir de modelos digitales del terreno”. Rev. Soc. Geol. España. 11 (1-
2). 139-149 pp.
SANCHEZ SERRANO, F. (2000). “Análisis de la topografía y deformaciones recientes en el
centro de la Península Ibérica”. Tesis Doctoral. 202 p.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 82-89
NATURALLY OCCURRING ARSENIC IN GROUNDWATERS OF
THE MADRID TERTIARY DETRITAL AQUIFER (SPAIN).
Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
High arsenic concentrations (up to 91 µg/L) have been measured in groundwaters from
the Madrid Tertiary Detrital Aquifer. These arsenic contamination phenomena in groundwaters
of the research area respond to natural causes. High arsenic levels appear in groundwaters
with high residence time, that is, they occur in groundwaters characterized by a) high pH values
(values between 8,3 and 9) and the resulting occurrence of CO =
3 anion, b) high sodium
concentrations, and c) low calcium and magnesium concentrations. Furthermore, the
groundwaters which display high concentrations of As show high levels of V, F and B. It´s very
interesting to note that the stable forms of these four constituents in aqueous systems are
anionic complexes. Consequently, it´s really possible that the concentration and mobility of As
could be controlled by anion exchange processes frequently related to evolved groundwaters
characterized by high pH values and tendency to softening. Moreover, arsenic release could be
affected by fluctuating water levels. Nevertheless, although the results of the preliminary
investigations do not confirm this hypothesis, it is not rejected.
The Madrid Tertiary Detrital Aquifer is one of the largest and most important aquifers
in all of Spain. This aquifer was declared a strategic resource for Madrid´s drinking water
supply in the Hydrologic Plan of Tagus Basin (Confederación Hidrográfica del Tajo, 1997).
Previous studies carried out by the the author of this paper revealed high concentrations of
arsenic in some water supply wells located in Madrid city (Hernández García, 1999). The
arsenic concentrations exceeded the maximum contaminant level established by the current
Spanish law for drinking water (50 µg/L). Taking into consideration the high toxicity of this
water constituent and the role of this sedimentary aquifer for the supply of the Madrid region, it
seems necessary to undertake a specific study to assess the magnitude of the problem and to
identify the arsenic sources. Furthermore, in December 2003 the European Directive 98/93/CE
related to the water quality for human consumption will come into effect in Spain. This
Directive will establish a maximum contaminant level for arsenic in drinking water of 10 µg/L;
consequently, the number of water supply wells affected by excessive concentrations of arsenic
will be increased substantially.
The study is focused on the Madrid Tertiary Detrital Aquifer. Four main objectives can
be distinguished: a) to research on the spatial distribution of arsenic in the groundwaters; b) to
assess the variability of the arsenic concentrations according to the groundwaters residence
time; c) to evaluate the correlation between the naturally occurrence of arsenic in groundwaters
and the aquifer mineralogy; d) to research on the most important mechanisms or processes that
control the incorporation of arsenic into the groundwaters.
METHODOLOGY OF RESEARCH
The methodology of research covered the next steps:
• Detailed bibliographic compilation related to the geology, the hydrogeology and the
hydrochemistry of the Madrid Tertiary Detrital Aquifer. Detailed bibliographic compilation
about other cases in the whole world of arsenic contamination in groundwaters.
• Detailed water well inventory of the Madrid Tertiary Detrital Aquifer.
• Description and sampling of the soil debris obtained during the execution of water wells to
perform subsequent geochemical analysis in the laboratory of the Geological Survey of
Spain (Instituto Geológico y Minero de España, IGME). 166 samples were obtained from 7
wells in order to analyse: Ag, As, Sb, Ba, Be, Cd, Ce, Co, Cr, Cu, La, Mn, Mo, Nb, Ni, P,
Pb, Se, V, Y, W, Zn, Fe, Al.
• Groundwater sampling to carry out field analysis of unstable parameters (temperature,
electrical conductivity, pH, redox potential and dissolved oxygen) and to perform
subsequent chemical analysis in the laboratory of IGME. 61 samples were obtained in order
to analyse TDS, organic matter, CO 3 = , HCO 3 - , SO 4 = , Cl - , NO 3 - , NO 2 - , NH 4 + , SiO 2 , PO 4 3- ,
Ca 2+ , Na + , Mg 2+ , K + , Al, Ag, As, Sb, Br, Ba, B, Cd, Co, Cr, Cu, Fe, Mn, Hg, Ni, Pb, Se, Sr,
Tl, V, F, Li, Zn. Sampling and preservation in the field were performed by the author
following a specific methodology (UNE-EN ISO 5667-3, 1996; Scalf et al., 1981). The
water was passed trough a 0.45 µm filter before analysis. Water samples were collected in
1L pre-washed polyethylene bottles. Water samples for the determination of cations and
heavy metals were preserved in the field with HNO 3 suprapure. Water samples for the
determination of anions and silica were preserved with refrigeration (4ºC). Table 1 shows
an extract from the analytic results.
• Data processing, data interpretation and securing of the objectives.
THE MADRID AQUIFER
Four main hydrological units can be distinguished in the Madrid region (see figure 1):
a) Central Range (2,500 km 2 ). It is formed mainly by schists and granitic rocks. The
permeability is low; b) Cretaceous limestone (200 km 2 ). They form isolated aquifers. The only
relevant is the one located near Torrelaguna, but its size (200 km 2 ) is small and its connection to
the Jarama river is high; c) Tertiary arkosic sands (2,500 km 2 ). They form the Madrid Tertiary
Detrital Aquifer. Its permeability is medium to low and its connected to the river is poor. The
available fresh ground water stored is at least 20,000 hm 3 . It may constitute the key element for
the future Madrid water supply (Llamas et al. 1996); d) Tertiary evaporite rocks (2,300 km 2 ).
Their permeability is low and the ground water salinity is high.
The sedimentary basin of Madrid is a large tectonic depression (6,000 km 2 ) filled with
continental deposits of Tertiary age. Sediments are detrital (arkosic sands, silts and clays) in the
vicinity of the surrounding mountains. Evaporites and limestones occur towards the centre of
the basin. Between these two types of sediments there is a transition facies, where is common to
find clay, marl, limestone and gypsum. The Madrid Tertiary Detrital Aquifer system is
constituted mainly by quasihorizontal lenses of arkosic sands surrounded by clay and silt. These
deposits are typical of a continental sedimentation of alluvial fans in a dry and warm climate
(López Vera, 1977). The thickness of the Tertiary deposits is usually greater then 1,000 m and
may be up to more than 3,000 m in the deepest parts. Estimated recharge of this aquifer is about
100-200 hm 3 /year. The recharge is mainly produced by infiltration of rainwater falling directly
on the Tertiary interfluves. The discharge occurs at the bottom of the valleys. Local,
intermediate and regional flow systems.
Table 1. Extract from the analytic results of groundwaters in the Madrid Tertiary Detrital Aquifer (Spain).
MUNICIPAL TERM REGION WELL TEMP. pH ELEC. COND. O 2 Cl - 2-
NO 3 Na + Mg 2+ Ca 2+ K + As V F B Fe Mn
DEPTH (m) (ºC) (µS/cm) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (mg/L)
Humanes Madrid 119 19.2 7.61 825 7 93 88 202 0 88 144 15 33 5
according to Toth’s scheme are apparently present. On a local scale hydraulic conductivity
changes sharply in a random fashion, but on a regional scale statistical studies have shown a
pattern in these changes according to the geology. As a first approximation, a homogeneous,
anisotropic, hydraulic conductivity is assumed. Horizontal conductivity is about 0.15 m/day;
vertical conductivity is from 100 to 1,000 times smaller (Martínez Alfaro, 1980).
The public water supply company called Canal de Isabel II (CYII) is responsible for the
water supply of 95% of the Madrid region population (about 5 million inhabitants). The great
majority of the water supplied by CYII come from fifteen surface reservoirs with a total
capacity of 960 hm 3 (see figure 1). The well fields of CYII are only exploited during drought
Figure 1. Schematic map of the Madrid region geology and the water supply system (Llamas et al., 1996).
HIDROGEOCHEMISTRY. MAIN FACTORS THAT CONTROL THE MOBILITY OF
As IN THESE GROUNDWATERS.
The predominant groundwater types in the Tertiary arkosic sands aquifer are a) Ca 2+ -
HCO - 3 , and b) Na + -HCO - 3 . The calcium bicarbonate type groundwaters represent the recharge
waters in detrital facies with low groundwater residence time. This type of groundwaters can be
captured with shallow wells in the interfluve zones. The sodium bicarbonate type groundwaters
represent high residence time waters within detrital facies. This type of groundwaters can be
captured: a) with shallow and deep wells in the discharge areas, and b) with deep wells (>400
meters depth, approximately) in the interfluve zones. The CO =
3 anion is present since the
hydrogen ion (H + ) undergoes exchange and/or takes part in silicate hydrolisis reactions. Because
of the decrease in the hydrogen ion concentration, pH values tend to increase. In general, pH
values increase gradually from recharge areas (values around 7) to descharge areas (values
between 8,3 and 9). Moreover, there is a tendency toward softening of groundwaters from the
recharge areas to the descharge areas: sodium concentrations tend to increase with the
groundwater flow in parallel with the decrease in calcium and magnesium concentrations,
maybe because of divalent/univalent exchange processes (Fernández Uría et al., 1985) and/or
clay minerals neoformation processes (Coleto, 1994).
Likewise, a gradually increase of arsenic concentrations from recharge areas (values
Figure 2. Scatter plot of total arsenic versus pH
(correlation coefficient: +0.5). Madrid Tertiary Detritic
6 7 8 9 10
Figure 3. Scatter plot of total arsenic versus cation
exchange ratio (correlation coefficient: +0.4). Madrid
Tertiary Detritic Aquifer.
(rNa + +rK + )/(rCa 2+ +rMg 2+ )
0,001 0,01 0,1 1
Figure 4. Scatter plot of total arsenic versus depth of
the well (correlation coefficient: -0.1). Madrid Tertiary
Well Depth (m)
Figure 5. Scatter plot of total arsenic versus vanadium
(correlation coefficient: +0.6 ). Madrid Tertiary Detritic
0,001 0,01 0,1 1
This paper has been prepared in the framework of a research grant given by the
Department of Education and Culture of the Community of Madrid (Consejería de Educación y
Cultura de la Comunidad de Madrid) and of a research contract with the Geological Survey of
Spain (Instituto Geológico y Minero de España, IGME).
BOYLE, D.R. (1992). “Effects of base exchange softening of fluoride uptake in groundwaters
of the Moncton Sub-Basin, New Brunswick, Canada”. In: Y.K. Kharaka and A.S. Maest (eds.),
Proceedings of the 7 th International Symposium on Water-Rock Interaction, Park City, Utah.
A.A. Balkema, Rotterdam: 771-774.
BOYLE, D.R.; TURNER, R.J.W.; HALL, G.E.M. (1998). “Anomalous arsenic concentrations
in groundwaters of an island community, Bowen Island, British Columbia”. Environmental
Geochemistry and Health. Vol. 20: 199-212.
COLETO FIAÑO (1994). “Modelización de la evolución química de las aguas subterráneas en
las Facies de Transición de la Cuenca de Madrid”. Tesis Doctoral. Universidad Complutense de
Madrid. Madrid: 1-200 (aprox.).
CONFEDERACIÓN HIDROGRÁFICA DEL TAJO (1997). “Plan Hidrológico de la Cuenca
del Tajo. Normas”. Ministerio de Medio Ambiente. Dirección General de Obras Hidráulicas y
Calidad de Aguas: 1-135. Difusión limitada.
FERNÁNDEZ URÍA, A.J.; FONTES, J.C.; HERRÁEZ, I. ; LLAMAS, M.R.; RUBIO, P.L.
(1985). “Tridimensional groundwater chemical and isotopic variations as related to the Madrid
aquifer flow system”. Estudios Geológicos. Nº 41: 229-236.
FROST, R.R.; GRIFFIN, R.A. (1977). “Effect of pH on adsorption of arsenic and selenium
from landfill leachate by clay minerals”. Soil Science Society of America Journal. Vol. 41. Nº
HEM, J.D. (1989). “Study and interpretation of the chemical characteristics of natural waters”.
U.S. Geological Survey. Water-Supply Paper 2254. Washington: 1-263.
HERNÁNDEZ GARCÍA, Mª E. (1999). “Estudio hidrogeológico, hidrogeoquímico y de
contaminación del Acuífero Detrítico Terciario en las áreas urbana y periurbana de la Villa de
Madrid”. Tesis Doctoral. Facultad de Ciencias Geológicas. Universidad Complutense de
Madrid. Madrid: 1-500 (aprox.).
IGME (1989). “Mineralogía de arcillas. Información complementaria al Mapa Geológico de
España 1/50.000, Hoja de Madrid (559)”. Instituto Geológico y Minero de España. Ministerio
de Industria y Energía. Madrid.
LLAMAS, M.R., VILLARROYA, F.; HERNÁNDEZ GARCÍA, Mª E. (1996). “Causes and
Effects of Water Restrictions in Madrid during the Drought of 1990/93”. Hydrology and
Hydrogeology of Urban and Urbanizing Areas. 1996 AIH Annual Meeting. American Institute
of Hydrology. Boston, Massachusetts. April, 21-26: WQD10-19.
LÓPEZ VERA, F. (1977). “Modelo de sedimentación de los materiales detríticos de la fosa de
Madrid”. XXXII Congreso Luso-Español para el Progreso de la Ciencia. Vol. 42, nº 4: 257-266.
MARTÍNEZ ALFARO, P.E. (1980). “Un primer análisis de la permeabilidad y el grado de
anisotropía de los materiales detríticos de la Fosa del Tajo”. Boletín Geológico y Minero. Vol.
PAUL, B.K.; DE, S. (2000). “Arsenic poisoning in Bangladesh: a geographic analysis”. Journal
of the American Water Resources Association. Vol. 36, Nº 4: 799-809.
PIERCE, M.L.; MOORE, C.B. (1982). “Adsorption of arsenite and arsenate on amorphous iron
hydroxide”. Water Research, 16: 1247-1253.
SCALF, M.R.; McNABB, J.F.; DUNLAP, W.J.; COSBY, R.L.; FRYBERGER, J. (1981).
“Manual of groundwater sampling procedures”. NWWA/EPA Series. NWWA. USA: 1-93.
UNE-EN ISO 5667-3 (1996). “Calidad del agua. Muestreo. Parte 3: Guía para la conservación y
la manipulación de muestras”. Versión oficial, en español, de la Norma Europea EN-ISO 5667-
3 de fecha diciembre de 1995, que a su vez adopta íntegramente la Norma Internacional ISO
5667-3:1994. AENOR: 1-39.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 90-94
THE ORIGIN AND SIGNIFICANCE OF PHOSPHORUS IN A
PERIURBAN, ALLUVIAL AQUIFER
HIMI, Y. 1 AND ALVAREZ-COBELAS, M. 2
1 Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
2 Centro de Ciencias Medioambientales (CSIC), Serrano 115 dpdo., E-28006 Madrid, Spain
Phosphorus is the key element in the eutrophication of freshwaters. This study reports
the origin, distribution and significance of phosphorus in diffrent aquatic environments of an
alluvial catchment close to Madrid (Central Spain). Originally as a point-source pollution, local
water fluxes partly drive phosphorus dynamics and its distribution within rivers, lakes and the
aquifer. However, other in-site processes, such as the production of organic matter in lakes and
rivers and the diffuse pollution of P-rich soils, must be considered to account for phosphorus
dynamics in this complex, anthrophogenically-forced landscape.
Nitrate is the preferred freshwater nutrient whose distribution is traced in groundwaters
(Fosters et al., 1986). The reason is the growing concern on the noxius effects of high levels of
nitrate on human health when groundwaters are used up for human consumption (Mirvish,
1991). This has been a research topic for almost twenty years worldwide (Thornton et al., 1999),
arising from the dramatic increase in global fertilizer application in modern agriculture.
Phosphorus, however, is considered the main limiting nutrient of primary productivity in
freshwaters (Vollenweider, 1968), and so its study has been promoted to tackle the
eutrophication problem that affects many surficial water bodies throughout the world (Harper,
1992). Notwithstanding this, phosphorus has seldomly been assessed in groundwater studies up
to date, and the few studies available (e.g. Hidalgo et al., 1997) only report scattered values
without any explanation on either origin, dynamics or relationships with any groundwater and
surficial component of the catchment. This is surprising in view of the many extant, seepage
lakes occurring in catchments which rely mostly on groundwater feeding (Winter, 1999).
Here our aim is to report a study on total phosphorus distribution in a periurban alluvial
aquifer close to Madrid (Spain). We will describe phosphorus concentrations in rivers, gravelpit
lakes and the alluvial aquifer and attempt to relate them with the prevailing water fluxes in
The Jarama alluvial environment is located SE Madrid (Fig. 1). It is now considered a
regional Natural Park (see further information in Díez-Olazábal, 1998, www.elsoto.org,
medioambiente.comadrid.es). The alluvial plain of the Jarama river and its three main tributaries
cover almost 150 km 2 . Pollution of both Madrid city (roughly 3.5 million people with partially
treated wastewaters) and the river Henares industrial belt (roughly 0.4 million people along with
many industries, whose pollution is not entirely treated either) enters the area. Two big and two
much smaller wastewater treatment plants, lacking tertiary treatment, are operating in the area.
More than one hundred gravel-pits have emerged mostly in the lower terrace of the river as a
result of gravel mining in the last thirty years (Roblas and García-Avilés, 1997). Geological and
hydrogeological descriptions of the area can be found in Peláez et al. (1971), Rebollo (1973)
and López-Vera (1977).
MATERIALS AND METHODS
Seventeen stagnant water bodies spread throughout the alluvial aquifer were sampled in
1998 and 1999 using standard limnological techniques (Wetzel and Likens, 1991). Total
phosphorus (TP hereafter) was measured in their vertical column seasonally following the
Murphy & Riley method (APHA, 1989). In November 2000, 45 wells were sampled for
phosphorus recording hydraulic head simultaneously (Fig. 2). Data for TP in rivers come from
the Spanish Tajo Water Authority and cover the 1994-1997 hydrological period monthly. We
have carried out some interspersed sampling in river waters since then and found no significant
deviations of total phosphorus from average behaviour of that period.
RESULTS AND DISCUSSION
Water level isopleths in the alluvial catchment suggest that rivers are water importers in
most sites (Fig. 3), and this input comes mostly from groundwaters. Depending upon their
relative position from such isopleths and their location in the valley, gravel-pit lakes may gain
and/or loose water from nearby rivers and the alluvial aquifer. TP ranges 0.56 ± 0.68 (average ±
1 SD), 1.69 ± 3.07 and 3.55 ± 1.91 mg/L for stagnant waterbodies, alluvial groundwaters and
the river Jarama, respectively. A Kruskal-Wallis test suggests that the three data sets of TP
contents vary markedly from each other (p < 0.05), that of groundwaters showing a very high
skewness to the left (Fig. 4). TP content of the alluvial aquifer shows three areas of peak values,
two of them in the vicinity of big wastewater treatment plants and the third one underlying an
irrigation reservoir located downstream of the joint of the Jarama with the organic loads coming
from Madrid city (Fig. 5).
Total Phosphorus (mg/L)
Gravel-pits Jarama river Groundwaters
Figure 5. Box-Whisker plots of total phosphorus content in the rivers, gravel-pit lakes and the
TP content in lakes is related to that of groundwaters in the following way:
TP lakes = 0.46 * (TP groundwaters ) 0.66 R 2 = 0.46 (p
elt and it is transported to the alluvial catchment through wastewater treatment plants (lacking
tertiary treatment). Despite the hydrologically gaining nature of the rivers, some phosphorus
enters the groundwater aquifer from streams, but the influence of rivers is limited by the
distance to both the sites of the aquifer and the gravel-pit lakes, i.e. the higher the distance the
lower the impact.
This study reveals the close coupling of TP dynamics in a complex hydrologic arena.
TP is primarily produced by nearby cities and factories, and it enters the Regional Park through
rivers from wastewater treatment plants. Then, if a given lake is close to a river, its TP content
arises from both the river and the aquifer, whereas if such a lake is located far away from the
river, then its TP is supplied by the aquifer. However, these results do not account for the whole
variability observed in gravel-pit TP. There are still two further sources of TP. First, in the
southern part of the catchment phosphorus-rich soils contribute TP to lakes via diffuse pollution.
Second, since lakes have no surficial outlet most organic matter (and hence organic phosphorus)
that they produce settles down and remains there, adding up to the phosphorus content of
surficial sediments, thus increasing phosphorus content in the lake through a positive feed-back
mechanism (Sánchez-Carrillo and Alvarez-Cobelas, 2001).
APHA, (1989). “Standard Methods for the Examination of Waters and Wastewaters”. 17th
edition. Washington D.C.
DÍEZ-OLAZÁBAL, P. (Ed.) (1998). “Parque Regional del Sureste de la Comunidad de
Madrid”. Federación de Amigos de la Tierra. Madrid. 155 pp.
FOSTERS, S.S., BRIDGE, L.R., GEAK, A.K., LAWRENCE, A.R. Y PARKER, J.H. (1986).
“The groundwater nitrate problem: a summary of research on the impact of agricultural land use
practices on groundwater quality between 1976 and 1985”. Hydrological Report of British
Geological Survey, 86/2.
HARPER, D. (1992). “Eutrophication of Freshwaters”. Chapman and Hall. London. 327 pp.
HIDALGO, M.C., CRUZ-SANJULIÁN, J.J. Y AGUSTÍN, C. (1997). “Contaminación difusa
en un acuífero detrítico debida al uso de fertilizantes y plaguicidas (Depresión de Baza,
Granada)”. Hidrogeología y Recursos Hidráulicos, 13: 73-96.
LÓPEZ-VERA, F. (1977). “Hidrogeología regional de la cuenca del río Jarama en los
alrededores de Madrid”. Memoria del Instituto Geológico y Minero de España, 91: 1-227 +
MIRVISH, S.S. (1991). “The significance for human health of nitrate, nitrite and N-nitroso
compounds”. In: Nitrate contamination (I. Bogárdi y R.D. Kuzelka, eds.), 253-266, Springer
PELÁEZ, J.R., PÉREZ-GONZÁLEZ, A., VILAS, L. Y ÁGUEDA, J.A. (1971). “Características
hidrogeológicas del Cuaternario del río Jarama”. Actas del I Congreso Hispano-Luso-
Americano de Geología Económica, Sección de Hidrogeología: 513-526.
REBOLLO, L. 1973. Estudio hidrogeológico del Cuaternario en la cuenca del río Jarama.
Tesina de Licenciatura. Facultad de Geología. Universidad Complutense. Madrid. 52 pp +
ROBLAS, N. Y GARCÍA-AVILÉS, J. (1997). “Valoración ambiental y caracterización de los
sistemas acuáticos leníticos del Parque Regional en torno a los ejes de los cursos bajos de los
ríos Manzanares y Jarama”. Documentos nº 24. Centro de Investigación Ambientales de la
Comunidad de Madrid. Consejería de Medio Ambiente y Desarrollo Regional. 128 pp.
SÁNCHEZ-CARRILLO, S. AND ALVAREZ-COBELAS, M. (2001). “Nutrient dynamics and
eutrophication patterns in a semiarid wetland: the effects of fluctuating hydrology”. Water, Air and
Soil Pollution 127: 12-27.
THORNTON, J.A., RAST,W., HOLLAND, M.M., JOLANKAI, G. AND RYDING, S.O.
(Eds.) (1999). “Assessment and control of nonpoint source pollution of aquatic ecosystems Man
and the Biosphere Series, 23. Unesco. Paris.
VOLLENWEIDER, R.A. (1968). “Scientific fundamentals of the eutrophication of lakes and
flowing waters, with particular reference to nitrogen and phosphorus as factors in
eutrophication”. OECD, París. 250 pp.
WETZEL, R.G. & LIKENS, G. (1991). “Limnological analyses”. Springer Verlag. New York.
WINTER, T.C. (1999). “Relation of streams, lakes, and wetlands to groundwater flow systems”.
Hydrogeology Journal 7: 28-45.
5 7 6
0 5 10 km km
: Exploitation of arid
: Military instalación of " Marañosa"
: Landfill of "Valdemingómez"
: Dump of industrial residuals
: Deposits of hydrocarbons
0 5 10 km km
: Wastewater treatment plants (WWTP)
: Gravel-pit lakes
Figure 1. Site location. The main anthropogenic impacts shown. Figure 2.
Sampling sites in the Jarama alluvial catchment.
TP (mg /L)
496 500 502
: Ground-water flow line
: Line of equal hydraulic head
0 5 10km
Figure 3. November 2000 isopleths of water level in the Jarama alluvial Catchment. Figure 4.
November 2000 isopleths of total phosphorus content in the Jarama alluvial atchment.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 95-101
HYDROGEOLOGICAL AND HYDROCHEMICAL STUDY OF
LOZOYA RIVER HIGH CATCHMENT (MADRID, SPAIN)
LÓPEZ BAHUT, M. T. 1 ; DE LA LOSA ROMÁN, A. 1 AND
REDONDO ARROYO, C. 1
1 Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
This work brings together the researches that are being carried out in the High Valley
of Lozoya. The main points of these researches are the study of the hydrogeological behaviour
in the area by means of a precipitation-runoff model; the surface water and groundwater
chemical quality; and the potential pollution sources. These works are based on the research
project LOWRGREP (Landscape-use Optimization With Regards of the Groundwater Research
Protection on the mountain hard rock areas) financed by the Fifth Framework Programme of
the European Community (Contract: EVK1-1999-00040).
The study area occupies the High Valley of Lozoya, which is located in the Northwest
of the Madrid Region. This valley is within the Guadarrama Sierra, on the eastern side of the
Spanish Central System.
This area covers approximately 250 km 2 and is one of the best conserved natural areas
of the Region, it serves as valuable site for geology (glacial geomorphology) and for ecology
(protected wildlife areas). The Natural Park of Peñalara and an Area of Special Protection for
Birds are located in the study area.
The valley opens towards the NE, forming the Lozoya River, which is the main stream
that crosses the area flowing north-eastward and discharges into the Pinilla Reservoir, which is
one of the twelve reservoirs that supply drinking water to Madrid city.
The climate of this area is Continental Mediterranean type, with long, cold winters, and
short, dry summers. Both temperature and precipitation show a clear variation with altitude. The
average yearly temperature is between 6º and 14ºC. The annual precipitation is between 600 and
900 mm/year in the lowest areas and between 1000 and 1500 mm/year in the areas situated at
more than 2000 m above sea level, searching as much as 2000 mm/year in some places [CAM
Broadly speaking, there are two lithological units over the high Lozoya catchment. One
is formed by hard rocks, mainly glandular granitic gneisses and, in minor rate, mica schist,
banded gneisses and metamorphosed limestones. They are high-grade metamorphic rocks
deformed by the Hercynian Orogeny forming the basin basement. Only a small plutonic outcrop
appears, which is a post-tectonic granitic intrusion. The other lithological unit is formed by
sedimentary rocks. They fill the basin lying over the metamorphic basement along an angular
erosive unconformity. These are:
- cretaceous sediments: sand, clay and gravel (Utrillas facies); marl and dolomites;
and karstified limestones
- tertiary sediments: polymictic conglomerates and sand cemented with carbonates of
Paleogene age; light ochre arkose type “Madrid facies” of Neogene age.
- Quaternary age sediments as stream alluviums including the lowest terraces of the
river; altered rocks and colluvial deposits on metamorphic rocks; peat deposits;
alluvial fans; glacial moraines; detrital filling in karst cavities.
The region suffered from two orogenies. The Hercynian Orogeny is responsible for the
main tectonic events. It has three principal phases of deformation, two light refoldings and two
of later faulting. During the Alpine Orogeny, it was produced the block faulting of the basement
and reworking of Mesozoic, Tertiary and even Quaternary sediments by means of either folds or
The Lozoya High Valley is an intramontane depression with rhomboidal shape. It is
result of the block dynamics (horst-graben) that occurred along the Miocene as consequence of
the alpine tectonic reactivation. The basic elements that form the valley structure are the slopes
of the mountain massif and its piedmont or valley bottom. Both elements have a clear separation
that generally coincides with the trace of the fault systems.
One of the southernmost glaciated areas during the Pleistocene is found in the Lozoya
High Valley. In this way, the Natural Park of Peñalara is the best example of glacial
geomorphology close to Madrid, where it can be seen morreins, glacial cirques, high mountain
lakes and periglacial process.
Hard rocks in the area (plutonic and metamorphic rocks) have secondary porosity
originated by alteration processes and joints (mainly of tectonic origin) that allows the
circulation of small amounts of water. At grater depths, the hard rocks are practically
impervious, because of closing fractures produces by the pressure of overlying rocks.
The weathering of hard rocks produces shallow aquifers, which generally have a
thickness of less than 10 m. They are small freatic aquifers that discharge in springs and
streams. The scarce water resources in this aquifers are use to supply water to cattle raising and
some country houses.
The hydrogeological interest in Utrillas facies depends on the clay proportion. Above it,
the marls and dolomites shown low permeability and this units are considered an aquitard. On
the top of the cretaceous series, there is karstified limestone that constituted an unconfined
aquifer of high permeability. The recharge of this cretaceous aquifer is produced by different
mechanisms: direct infiltration of precipitation; infiltration of tributary streams of the Lozoya
River while passing through these permeable rocks; and the recharge from the Pinilla Reservoir.
In a natural flow regime, the discharge is produce towards the Lozoya River and the reservoir.
The tertiary sediments constitute an unconfined aquifer of less importance than the
Except alluvial deposits and the valley bottom which constitute the alluvial aquifer of
the Lozoya River, the rest of quaternary sediments form unimportant unconfined aquifers that
discharge into small spring located along the contact with the impermeable basement.
As a whole, the cretaceous and tertiary sediments, and the alluvial deposits overlap one
another and follow the tectonic fracture structure of Lozoya High Valley. There is a perfect
hydrological connection between the aquifers and rivers that forms a common a continuous
HYDROLOGICAL BALANCE. THE USE OF A PRECIPITATION-RUNOFF MODEL.
The methodology is summarised in the following steps: 1. Bibliographic compilation;
2. Springs and wells inventory; 3. Monthly stream-gauging in four experimental catchments
during the hydrological year 2000-2001; 4. Meteorological data processing; 5. Unified
cartography with types of soils and their uses.
The precipitation-runoff model will be used in four experimental catchments from the
assessment of the evapotranspiration through the data of precipitation, irrigation and soil
moisture. After the study has been completed, the results will be extrapolated to the rest of the
HIGH LOZOYA VALLEY
Pe ña la ra
0 2 4 6 8 Km
Figure 1. Situational geological map. Lithology: 1) glandular granitic gneisses; 2) granitic intrusion 3) Cretaceous
sediments: karstified limestones; marl and dolomites; sand,clay and gravel 4) Tertiary sediments; 5) Quaternary
The computer model chosen for this work is the CHAC 1 , which has been developed by
the CEDEX 2 that belongs to the Ministry of Public Works in Spain. The inputs of the model are:
monthly rainfall data; water level and daily flows data in the stream-gauging stations; average
monthly temperature; humidity; wind rate; and insolation for the assessment of the potential
evapotranspiration; and soil moisture content for the assessment of the real evapotranspiration.
In the study of rainfall, several stations were selected in the area and later, in order to
achieve a more detailed data correlation, other stations located outside the study area were
added. The method of Double Accumulation was applied in the critical analysis of the rainfall
data. This method is based on the comparison of the data of one station with its environment.
The yearly accumulated values of one station are plotted versus either the values of another
reliable close station, or the arithmetic or weighted mean of a group of stations. The data form
on a straight line. From the analysis of these graphs, anomalies in the working order of the
stations were detected and corrected and, consequently, some of the stations were eliminated
from the study.
The CHAC program completed automatically the rainfall data sequence with a tool
based on the CORMUL model. Based on the use of the spatial correlation between the
variables, this random interpolation model was developed in the Centre for Hydrographic
Studies of the CEDEX.
1 CHAC (Cálculo Hidrometeorológico de Aportaciones y Crecidas): Hydrometeorological Assessment of inputs and
2 CEDEX (Centro de Estudios y Experimentación de Obras Públicas): Centre for Research and Experimentation of
Since the rain-gauge network is not uniform, the isohyetal method will be used. In
drawing the isohyets, such factors as known influence of topography on precipitation can be
taken into account.
There are two stream-gauging stations in the study area. They belong to the Tagus’
Hydrographic Confederation, which has provided us with stream-gauging data for the period
between 1967 and 1995. The determination of a lengthy and reliable sequence of monthly input
data in the Lozoya River will enable the evaluation of the renewable water resources in the
study area. There again, monthly stream-gauging operations are being carried out in four
experimental catchments that have been chosen according to the hydrogeological behaviour of
its materials and the features of the terrain – slope, vegetation, etc. These operations are
performed in the contacts between different materials. The aim is the assessment of the runoff in
every hydrogeological unit.
The potential evapotranspiration will be assessed by means of the Thornthwaite
equation, which is function of the average monthly temperature, relative humidity, wind
rate and insolation. The CHAC program makes the calibration of the maximum soil
moisture to estimate the real evapotranspiration. In order to work with real values, these
data will be validated by a soil sampling campaign.
The rainfall-runoff model is carried out with the Temez rational formula of continuos
simulation . This model assumes that the terrain is divided in two zones: the upper
unsaturated zone in which the pore spaces contain water, as well as air and other gases; and the
lower zone or aquifer in which the voids in the soil are filled with water. The model also
assumes that one part of rainwater is drained and goes out joining with the water flow of the
river, while the rest of the water is stored in the upper area of the soil, serving later for the
evapotranspiration. One part of the rainwater surplus flows on the surface and the other is
infiltrated into the aquifer. The parameters of this model are: maximum soil moisture; surpluses;
maximum infiltration capacity; and the discharge coefficient. The rainfall-runoff model will be
calibrated with all these parameters.
CHEMICAL QUALITY AND SOURCES OF POLLUTION
The main aim of this study is to achieve the description of the hydrogeochemical
characteristics of the continental water, in order to know what hydrochemical processes
occurred and estimate the possible impact of pollution sources on the quality of water in the
The methodology of the hidrochemical study consists of the following stages:
1. Geological and hydrogeological data compilation; 2. Field work in which the springs and
wells inventory was expanded and the potential sources of pollution were identified; 3.
Selection of the most suitable points for the annual control network carried out with monthly
samplings; 4. Samplings with “in situ” measurements of unsettled parameters (pH, temperature,
electrical conductivity and alcalinity); and 5. Sample laboratory analysis and interpretation of
results. The cation analyses were made with ICP-MS, while anions were analysed with ionic
Results and discussion
The results obtained in the monthly samplings so far, shows that, in most cases, the
water shows a very low or low salinity (with conductivity under 200 µS/cm), with pH values
around 6-7, and calcium-bicarbonate hydrogeochemical facies.
pH T ºC Cl -
CO 3 H -
Maximum 1850 8.2 13.5 38 1122 248 13.6 313 98.7 11. 12.6 13.9
Minimun 18 5.7 6.2 0.8 < 0.9 8 0 1.1 0.2 2.1 0 0
Average 176 6.5 9 5.4 43 58 4.7 23.4 6.9 4.2 1.7 7.1
Table.1. Summary of the chemical analyses of groundwater and surface water of Lozoya catchtment (29 analyses)
However, as the Schoeller-Berkaloff diagram (Figure 2) shows, there are two types of
water according to the lithology of the terrain where the wells, springs and streams are located.
On the one hand, springs and rivers in hard rocks have water with very low salinity, with
conductivity values between 18 and 95 µS/cm, and less than 40 and 8 mg/L of bicarbonate and
calcium respectively. But on the other hand, springs and wells on the sedimentary aquifer have
bicarbonate and calcium as major ions, reaching values of 35 and l55 mg/L respectively.
Ca Mg Na + Cl - 2- - -
RIVERS AND SPRINGS IN HARD ROCKS
WELLS AND SPRINGS IN SEDIMENTARY ROCKS
FRAGUA WELL (POLLUTED)
Another difference between these
two types of facies is the content on Mg 2+ .
Continental water on hard rocks has
concentrations under 3 mg/L, while
groundwater, circulating across sedimentary
rocks, has concentrations above 3 mg/L until
Both hydrogeochemical facies have
in common a low content of chloride and
sodium, with maximum values of 12 y
In Figure 2, an analyses of a drilled
well (Well of Fragua) is also represented.
This well is placed on limestones, and the
chemical quality of its water notably differs
from the other springs and wells. It has high
salinity and calcium sulphate
hydrogeochemical facies that appear to have
an anthropic origin.
Figure 2. Scholler-Berkaloff diagram
Besides the major components
shown in Table 1, 60 minor and trace
elements were analysed. Between them,
there are the inorganic contaminants used as
indicators to determine the potability of
water (Ag, Al, As, B, Ba, Be, Cd, Cr, Cu, Fe,
Hg, Mn, Ni, Pb, Sb, Se, etc.). The amount of
these elements are much lower than the
potability limit values established by both
the current Spanish legislation [BOE 1990]
and the more restrictive new European
Directive proposal [OJEC 1998]. Neither
reached the inorganic trace elements limit
values proposed by the Environmental
Protection Agency of USA [EPA 1998].
In only a few cases, the limit values established by the drinking water legislation are
exceeded. This happens in the Well of Fragua where the water has 2,257 µg/L of Zn. Also in
The Eras Fountain whose concentration of Al is 275 µg/L, exceeding the limit value of 200
µg/L established by the European and Spanish legislation.The values of nitrogenous species are
low in every sample. None of the samples have values above 14 mg/L of NO 3
, whose origin can
be considered natural rather than anthrophic. As would be hoped, the values of nitrites are the
lowest of the nitrogenous species (never above 0.03 mg/L of NO 2 - ).
Figure 3 shows the potential continental-water sources of pollution in the study area.
HIGH LOZOYA VALLEY
Pic nic Are a s
Ski Re so rt
Pe ña la ra
Gas Station Natural Park
0 2 4 6 8 Km
Figure 3. Potential continental-water source of pollution. Lithology: 1) glandular granitic gneisses 2) granitic
intrusion 3) Cretaceous sediments: karstified limestones; marl and dolomites; sand, clay and gravel 4) Tertiary
sediments: 5) Quaternary sediment
It can be seen that most of the sources occupy a low extension and are located in the
sedimentary aquifer. Outside, on hard rocks, the human presence is only represented by picnic
areas and non-stabled cattle with 5,000 head of cattle. There are more cattle raising activities in
the area, but they are not significant.
The high salinity of its groundwater, rather than by limestone dissolution, in some cases
is produced by the pollution in the sedimentary aquifer. A clear evidence of contamination is
seen in the Fragua Well, which is placed on the limestones of the sedimentary aquifer. Figure 2
shows that its chemical composition is totally different from the results of the other 28 analyses.
The Fragua Well has a very high content of sulfates (1,122 mg/L). Its content of nitrates is only
of 1.2 mg/L, but it has 5.4 mg/L of NH 4+ . The high content of this unstable specie and the
location of the well, close to a population centre, make it possible to think that it is affected by a
leak of the nearby sewer system.
The low concentrations of nitrogenous species in the samples, both in groundwater and
surface water, (excepting the already discussed case of the Fragua Well), show that the cattle
raising in the area does not produce a significant impact in the quality of the continental waters.
However, it is advisable to take into account that precipitation during this winter has been very
important and during this time, (coinciding with the field campaign), the cattle have occupied
the lowest areas of the Lozoya High Valley. During the summer, when the water in rivers and
springs significantly decreases and the cattle are around the slopes of the basin, it is more
probable to detect higher values of nitrogenous species. This hypothesis will be confirmed with
future results of the chemical control network installed in the area.
The different researches carried out in the High Valley of Lozoya will serve a more
detailed knowledge, favourable assessment and sustainable development of the area. They
achieve a great importance due to the purpose of declaring the Guadarrama Sierra Natural Park.
A Geographic System of Information (GIS) will be devise as an answer to the need of a
better territorial organisation.
The translation by Carmen Martínez Pérez-Herrera is fully appreciated and gratefully
BOE (BOLETÍN OFICIAL DEL ESTADO – SPANISH OFFICIAL BULLETIN) (1990). Law
1138/1990 of 14 September concerning the technical-sanitary regulation that refers to water
supply and control of potable water quality, pp. 27488-27497
CEDEX ( CENTRE FOR RESEARCH AND EXPERIMENTATION OF PUBLIC WORKS)
“Estudio Hidrológico de la presa de Velillos. Estimación de aportaciones”. Madrid
COMUNIDAD AUTÓNOMA DE MADRID 1985. “Mapa fisiográfico de Madrid”. Escala
1:200.000. Consejería de Agricultura y Ganadería. Memoria 42 pp. Madrid.
ENVIRONMENTAL PROTECTION AGENCY 1998. “National Recommended Water Quality
Criteria; Notice; Republication”. Federal Registre 237 (63): 68354-68364.
INSTITUTO TECNOLÓGICO GEOMINERO DE ESPAÑA 1991. “Mapa Geológico de
España”. Escala 1:50.000. Hoja nº 484 (Buitrago de Lozoya). 105 pp. Madrid.
MARTÍN-LOECHES, M., MUÑOZ, I., SASTRE, A. & VICENTE, R. 1997. “Brackish
groundwater manifestations in the meridional limit of Spanish Central System”. In J.G.
Yélamos & F. Villarroya (ed.), Hydrogeology of Hard Rocks. Some experiences from Iberian
Peninsula and Bohemian Massif; Proc.symp., Madrid, 11-13 September 1997. Madrid: AIH-
OJEC (OFICIAL JOURNAL OF THE EUROPEAN COMMUNITIES) 1998. Council Directive
98/83/EEC of 3 November 1998, concerning water quality for human consumption. OJEC of 5
December 1998, pp.32-54.
TEMEZ, J.R. (1977). “Modelo matemático de transformación precipitación-aportación”. Asinel,
VICENTE, R. 1986 “Hidrogeología regional de la Depresión de Campo Arañuelo”. Ph Thesis.
376pp. Department of Geology, University of Alcalá de Henares.
YÉLAMOS, J.G. 1991. “Hidrogeología de las rocas plutónicas y metamórficas en la vertiente
meridional de la Sierra de Guadarrama”. Ph Thesis 334 pp. Department of Q.A. Geology and
Geochemistry, Autonomous Universtity of Madrid.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 102-106
PRELIMINARY SEDIMENTOLOGICAL AND
GEOMORPHOLOGICAL EVOLUTION IN A PART OF THE
GUADIANA BASIN BETWEEN MÉRIDA AND BADAJOZ (SPAIN)
MOYA-PALOMARES, M.E 1,2 ; CENTENO, J.D 2 AND
AZEVEDO, T.M 3
1) Department of Geology. Faculty of Environmental Sciences. Alcalá de Henares University. Madrid (Spain)
2) Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
3 Department of Geology. Faculty of Sciences. Lisboa University. Lisboa (Portugal)
We are approaching to the sequence of the sedimentary and morphological events
taking place at the Guadiana basin in the Vegas bajas area. The litostratigraphical correlation
with other basins of the western Iberian Peninsula allows to explain the main evolution stages
of the basin.
This work will be the PhD Thesis of M.E. Moya under the suprevision of the other
authors of this article, thas is an advance to the definite version.
Estamos estableciendo a la secuencia sedimentaria y los procesos morfológicos que se
sucedieron en la cuenca del Guadiana para el tramo de las Vegas bajas. Se destaca las
correlaciones litoestratigráficas con otras cuencas peninsulares que sirven de ayuda para
explicar la evolución de la cuenca.
The study of the morphological and stratigraphical evolution of the Guadiana Basin in
the Extremadura area of Vegas Bajas (VB) is a research program of the Department of
Geodynamic of the Complutense University.
The present work is focused to establish the morpho-sedimentary process since the first
deposit of the Tertiary until the sedimentation of the quaternary deposits into the Guadiana VB.
The main data used to carry out the present work are:
- Bibliografic data.
- Sedimentological data.
- Morphological data.
The sedimentological and geomorphological data of other Iberian Cenozoic basins was
specially contrasted in order to correlate and propose an evolution model to the VB area.
The Guadiana crosses Extremadura along a small tertiary basin located at the SW of the
Iberian Peninsula (Fig.1) in wich two separated basins can be defined: Vegas altas and Vegas
bajas ( Hernández- Pacheco, 1932). We are studying the Vegas Bajas (VB) sector that represent
the area from the batholito of Mérida until Badajoz. In this sector of the basin, the Guadiana
River flows E-W. Once the river cross the town of Badajoz, it changes its direction flowing
towards the South, fitted into the Palaeozoic rocks.
Fig.1 Location map of the
Guadiana central basin in the
iberian Peninsula. Fig. 2.
Simplified geological map of
the area between Mérida and
SEDIMENTARY CENOZOIC UNITS IN THE GUADIANA BASIN BETWEEN
MÉRIDA AND BADAJOZ
The sedimentary study allows to define four basin Unconformity Limited Sequences
during the Cenozoic: ULS1, ULS2, ULS3 and ULS4 (Fig.3) .
• The ULS1 unit is formed mainly by clay and sand, with thickness less than 80 meters
(Hernández-Pacheco,1960). This unit is lays discordant on the Iberian Massif substrate.
ULS1 is interpreted as distal alluvial fans of the Oligocene (Hernández-Pacheco, 1932,
1955) or Miocene (Hernández-Pacheco and Crussafont, 1960), being the last idea the most
widely acceted nowadays (Villalobos et al., 1988).
• The ULS2 unit is characterised by sand, conglomerates and, at the top of the unit, a
carbonate deposit (caleño). The units is widely accepted as Miocene (Hernández
Pacheco,1960; Villalobos et al.,1988). The facies analysis shows the characteristic of a
braided system flowing from E to W, related with the present fluvial system. The
palaeocurrent measurements in the sandy bodies revealed a direction very similar than the
actual flow of the Guadiana river with values of 230º to 270º.
Mainly temporary inactive channels and bars composed this fluvial system. Toward the
southern edge of the basin, fans associated to a pre-existing relief prograde rapidly into the main
Fig.3 Summarised vertical Cenozoic units (ULS1, ULS2, ULS3 and ULS4) between Mérida and Badajoz.
The presence at the top of the unit of 1-2 meters of carbonate lacustrine deposit
(Armenteros et al., 1986), represents the end of sedimentation in the basin during the Miocene.
Other authors considered that this carbonates sheet (caleño) is pedogenic, similar that the
“caliche capro” of New Mexico ( Elbersen, 1982).
After the fill-up of the basin, the fluvial system is reactivated due tectonic processes or the
connection to the Atlantic basin by fluvial captures.
• The ULS3 unit is a deposit of gravel and sand of braided fluvial system, formed by cannel
and bars (fig 4,5). The palaeocurrent measurements in ULS3 revealed an S-W flow
direction (values 225º to 315º). These palaeocurrent ranges indicate that the streamflow
direction is similar than the ULS2 unit. However, to W of the VB the direction of ULS3 is
• The ULS4 unit has been identifies as raña 1 deposits in the Vegas area. That deposit was
sedimented in form of aluvian fans of pediment pebble-sheets. They are generally dated as
transitional between the Pliocene and Pleistocene. Most of the stone and gravel, which are
angular, are embedded in a matrix of sand and clay and occur as lenses.
Raña Gt,St is the Spanish and Portuguese name for a conglomarate of quartzite pebbles, poorly rounded and covered by a
ferric patina, into a clayish matrix, very common at the piedmont area of the Iberian massif quartzite ridges. Most
rañas have been deposited in the Pliocene-Pleistocene limit, and their fan-like form is still to be recognised.
– 70 cm
Fig 4, 5: ULS 3 formed by bars ( fig4) and cannels (fig 5)
The block diagram (fig. 6) shows a possible interpretation of the Guadiana Basin from
the Paleogene to the Plio-Pleistocene with the present day data.
The age of the different units is still a question without a solution. There are very few
palaeontological remains and clay minerals have been used to date the deposits by correlation
with other cenozoic basins (Brell, 1975).
ULS1 has paligorskite>montmorillonite>illite. These minerals appear systematically in
other cenozoic basin, toward the west of the Guadiana. The basins of the Tajo, Sado, Moura-
Marmelar and Beira alta (Mondego), are characterised by the same clay mineral association, and
that sediments are paleogene age.
On the other hand, the clay mineral in ULS2 unit is composed by
montmorillonite>illite, while paligoskinte is not present. This clay mineral association is present
in previously mentioned basins and is dated as Miocene.
Finally, ULS3 and ULS4 have kaolinite>illite. In the Portuguese basin (Tajo, Sado,
Moura-Marmelar and Beira Alta) this association are present in Pliocene and Quaternary age.
As a tentative hipothesis, we can consider ULS3 as Pliocene and ULS4 as late Pliocene or early
Fig. 6. Preliminary interpretation of the evolution in the Guadina basin between Mérida and Badajoz during : A)
Paleogene. B) Miocene. C) Pliocuaternary. D) in the present day. Moya et al., (1999, 2000 a,b)
The Guadiana basin received its first sediment input during the Paleogene with the
sedimentation of ULS1 in a closed basin.
During the Miocene began the fluvial sedimentation in a open basin. The sediments in
this phase are sands of a braided system with palaeocurrents towards for the west (ULS2 unit).
Probably, the fluvial sedimentation continued outside the Vegas bajas towards the west into
Portugual. The fluvial sedimentation was interrupted at the late Miocene when the “caleño” is
In the early Pliocene age, a new fluvial system is identified. This system presents
important differences with the miocene fluvial system. It is a gravel and sand braided system
with palaeocurrents towards the west between Mérida and Badajoz and towards the south
around Badajoz city. In this case, the flow of the pliocene system is similar to the present.
Once we have done the study and interpretation of the sedimentary filling of the basin,
we proceed to study the geomorpholigical units, their relations with the filling up and the
following stream network entrenchment, and the evolution of the present valley landforms and
ARMENTEROS,I.; DABRIO, C.; ALONSO, G.; JORQUERA, A. & VILLALOBOS, M.
(1986) “Laminación y bioturbación en carbonatos lagunares interpretación genética (cuenca del
Guadiana, Badajoz)”. Estudios Geológicos, 42: 271-280 pp.
BRELL, J.M. (1975) “Aplicación de las correlaciones al estudio del terciario continental”.
Congresos y Reuniones Enaddimsa, Serie 7; 2 pp.
ELBERSEN. G.W.W (1982) “Mechanical replacement processes in mobile sofl cacic horizons.,
their role in soil and landscape genesis in an area near Mérida, Spain”. Thesis. Agricultural
Research reports, 919. 1-208 pp.
HERNÁNDEZ PACHECO, E. (1932) “Síntesis fisiográfica y geológica de España”. Trab,
Museo Nacional Ciencias Naturales, 38. 584 pp. Madrid.
HERNÁNDEZ PACHECO, F. (1955) “Fisiografía del solar hispano”, Tomo I. Real Academia
de Ciencias Naturales. Madrid.
HERNÁNDEZ PACHECO, F. (1960). “El terciario continental de Extremadura”. Boletín de la
Real Sociedad Española de Historia Natural, 58. 241-274 pp.
HERNÁNDEZ PACHECO, F. & CRUSAFRONT, M. (1960). “La primera caracterización
paleontológica del Terciario de Extremadura”. Boletín de la Real Sociedad Española de Historia
Natural, 58. 275-282 pp.
MOYA PALOMARES, M.E.; AZEVEDO, M.T. & RODRÍGUEZ-PLAZA, M. (1999).
“Estudio preliminar de los sistemas fluviales Cenozoicos de la cuenca del Guadiana entre
Mérida y Badajoz (España)”. Congresso Nacional Cenozoico de Portugal. Lisboa.
MOYA PALOMARES, M.E.; AZEVEDO, M.T.; CENTENO J.D & RODRÍGUEZ-PLAZA,
M. (2000a). “Interpretación de las facies fluviales de la unidad superior terciaria y
pliocuaternaria en la cuenca del Guadiana”. Congreso Ibérico sobre el Terciario. Barcelona.
MOYA PALOMARES, M.E.; AZEVEDO, M.T. (2000b) “Los sistemas fluviales Cenozoicos
de la cuenca del Guadiana”. Revista Ciencias da Terra, nº12.
VILLALOBOS, M.; JORQUERA, A.; APALATEGUI, I. (1988). “Hoja núm. 802 (La
Albuera)”, 1:50.000 segunda serie.IGME.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 54-
PRESENT AND PAST FLOODS IN THE GUADIANA RIVER
BASIN: HYDRO-AND PALEOHYDROLOGICAL APPROACH
ORTEGA, J.A. 1 AND GARZÓN, G. 2
1 Faculty of Sciences. European University, CEES. Madrid (Spain)
2 Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
The 1997 Rivillas flood, a tributary of the Guadiana River in the town of Badajoz, was
one of the most catastrophic in the Iberian Peninsula in recent years. This study first
establishes the dynamics of the flood and associated deposits, and from there estimates the
ensuing flow magnitude. In order to establish flood frequency analyses for the Guadiana River,
annual peak discharge estimation on surrounding gauging stations, historical records and
paleostage indicators have been integrated. Using paleohydrological techniques, at least seven
floods, starting from 3260BP, have been identified as slackwater deposits. At least three of these
floods were larger than the greatest on historical record, the one of 1876 AD.
There is a long historical record of flooding in the Guadiana Basin. Unfortunately there
are very few cases in which there are sufficient hydrological data on record for reliable
reconstructions of return periods. In Nov. 1997, one of the most destructive flood disasters in
the Iberian Peninsula in recent years occurred in the Rivillas stream, affecting the town of
Badajoz and causing 23 deaths and material losses estimated at $ 150 M. These figures were
unexpected for a small tributary of the Guadiana river (Fig. 1), only 34 km long with a 314 km 2
lowland watershed, and must rather be related to the flashflood character of the event and the
environmental conditions on the floodplain [Ortega et al., 1998; Moya et al., 1998].
In the Rivillas Stream, on the basis of the flood in 1997, the discharges were estimated
using a variety of methods: first, the rational method (as modified by Temez, 1978) and then
hydraulic calculation programs (HEC-RAS). Paleofloods in the lower basin of the Guadiana
river were studied using paleoflood hydrology techniques in order to estimate peak discharges.
There is a voluminous historical record for the Guadiana, which in some cases made it possible
to establish relations between slackwater deposit-paleostage indicators (SLW-PSI) and
historical floods by dating some of the deposits using the C14 standard and AMS methods.
Verifications were also made by Cs 137. SLW-PSIs produce the most accurate estimates of
paleoflood magnitudes (Baker,
1987) and can be combined with the HEC-RAS hydraulic calculation program to establish
ESTIMATIONS OF RIVILLAS STREAM DISCHARGE AND FLOOD RETURN
The Rivillas stream is 34km. long with an average slope of 0.5% and an area of 314
km 2 , formed by tertiary sands and clays with low infiltration rates. Its main tributary, the
Calamón creek, approaches the Rivilla very close to its mouth, so that there are in fact two very
similar subbasins, parallel to each other and with the same orientation (Fig.1). An immediate
survey of the ephemeral flashflood deposits was carried out in order to interpret the resulting
sedimentary features and reconstruct water levels. Hydrologic modeling provided the flood
discharge estimation. The question addressed was the relative importance of this flood in a
historical context and the possibility of establishing a return period for the event. At least 12
floods had been recorded for the Rivillas river since 1700, some of them of even greater
magnitude than the present one. Most of them, however, were produced not by storms at the
Rivillas watershed, like this one, but by backwater effect of floods in the Guadiana river that
obstructed the confluence between the two.
Rainfall data for the Rivillas basin given by the INM (1998) reveal figures as high as
130 mm in 24 hours, and an intensity of up to 88mm/h. The rainfall had been the heaviest in the
historical records for the area, which go back nearly 100 years. The closest and most reliable
rain gauge station for the area, at Talavera la Real, registers a record of 117mm/day for the data
series from 1961 to 1990, and this is the figure that was used for the calculations. The SQRT-
ETmax distribution function approach was used as the most suitable for this type of events, both
including and excluding the 1977 event precipitation data. According to this, the return period
for the rainfall in the region was within the range of 500 years.
Return period 24 hours Precipitation 24 hours Precipitation
(without the 1997 event) (including the 1997 event)
25 years 67 mm 71 mm
100 years 84 mm 91 mm
500 years 107 mm 116 mm
A first discharge estimation using the rational formula modified by Temez  gave
discharge for the Rivillas subbasin as 396m 3 /s, calculated for rainfall of 120mm, the figure
obtained for the whole basin from the rainfall isolines map supplied by the INM. In
another approach, two methods were used to reconstruct the water levels on a selected field
0 5 Km
Pulo do Lobo
Figure 1. Location of Rivillas River and studied reaches in the Guadiana Basin
one by means of a detailed field survey of water level marks, and the other based on the storm
hyetograph. The hyetograph was drawn up with the storm rainfall data supplied by the INM,
and from it the flood Unitary Hydrogram (SCS) was obtained using HEC-1 [U.S. Army, 1981].
A flood discharge of 160m 3 /s was calculated for the reach in question. This discharge was used
to reconstruct the extension of the flooded area by means of Hec-Ras [U.S. Army, 1997]. These
data were validated by detailed field survey. According to these results, at the outlet from the
Rivillas subbasin, the discharge for the reach would produce a flood peak discharge of 356m 3 /s
calculated by Hec-1. This figure is similar to the official estimation for the flood, that is 375
m 3 /s [CEDEX, 1998] and only a little smaller that the one arrived at by the rational formula, as
is normally expected from this method. However, it was difficult to evaluate these data in an
historical context since there are no available data on discharge in other floods. Historical marks
are related to floods caused by a rise in the waters of the Guadiana and not by water of the
SLACKWATER DEPOSITS AND PALEOHYDROLOGICAL ANALYSIS
Historical flooding on the Guadiana basin was examined in order to understand the
significance of floods in the context of that basin (Ortega & Garzón, 1997). Two populations
can be identified from the distribution of Guadiana floods. Autumn floods are in general
scattered and isolated along the watershed and bear no immediately apparent relationship to
annual rainfall data. Winter floods, on the other hand, are associated with the trunk stream and
fall mainly in wet yearly periods. The Rivillas flood, although belonging to the autumn group
generated in small basins, is also associated with a three-year wet period.
Systematic gauge station records for the Guadiana River, and for most of the Iberian
Peninsula, begin in 1912. However, only a few stations preserve a continuous, reliable record on
which to base detailed hydrological reconstructions. In the towns of Badajoz and Merida, as in
various other riparian towns of Spain and Portugal, there are historical marks defining the height
reached by the waters. All these marks indicate that the highest flood-level on record is that of
1876. With an estimated discharge of 10,000m 3 /sec at Badajoz, this flood is considered a major
point of reference for estimations of return periods.
Since much of the course of the Guadiana runs through deep gullies in the Hercynian
massifs, we decided to look for paleo-flood deposits in these areas. Various sites of such
deposits have been located, although these areas generally present difficulties of access and
excavation. Our goal in this study was to determine low-frequency, high-flow flood peak
discharges. These floods are not recorded at the gauge stations, which were built much more
recently than the sedimentary register that we have compiled. The Guadiana canyon in the Serpa
area (Portugal) was chosen for its good depositional conditions, the possibilities of hydraulic
modeling, and also because there is a gauge station with records going back to 1947. This reach
of the river is enclosed by metamorphic materials forming a steep-sided gorge. The valley is
400m wide. The surface area of the Guadiana in this reach is 60,800 Km 2 .
Most of the slackwater deposits studied are composed of fine to very fine sand and silt.
In some cases these are arranged as couplets or pairs of coarser and finer material which
intercalate as the result of a single impulse in zones favourable to deposition. Both deposits
correspond to the various energy phases that the flood goes through: first, a stronger impulse
with rapid loss of competence and deposition of coarser material, followed by a halt in which
the finer fractions left in suspension are deposited. The various units are separated by coluvial
levels and differences in size and bioturbation.
Two methods have been used to date the SLWs. One is Cs 137 (Ely et al, 1992), used to
determine whether the deposit is earlier or later than 1952, the year in which the nuclear
emissions of this element first began. The other and principal method is C14. Analysis by the
C14 Standard method has shown that results are not always very satisfactory in these cases, and
we therefore separated the organic fraction (charcoal & branches) from the inorganic fraction by
washing and flotation followed by drying, according to the method suggested by House
(personal communication), and samples were dated with C14 AMS technique by BETA Lab.
The hydraulic model was built up following the SWD-PSI methodology (O´Connor &Webb,
1988, House & Pearthree, 1995). The mathematical model used was Hec-Ras version 2.0,
developed by the Hydrologic Engineering Center (Hec-Ras, 1997), with stationary flow and step
backwater flow characteristics.
According to these results, the datings suggest that there have been at least three floods
larger than that of 1876AD, which is considered one of the largest in the area on the basis of the
historical records. These floods could be probably related with historical floods recorded
1758AD and 1603AD and a very old one with an approximate age of 3260BP.
DISCUSSION AND CONCLUSIONS
The effects of the flooding of the Rivillas stream in November 1997 were surprising for
the seriousness of the damage and above all for the number of victims. The flow rate data from
field measurements of water levels agree closely with the figures estimated indirectly from the
rainfall recorded at the meteorological stations. The estimated return period for this rainfall is
500 years. While there are records of higher floods on the lower reach of the Rivillas, these
were due not to flash floods like the present case but to floods caused by rising of the Guadiana
River which restricted the drainage capacity of the Rivillas. The seriousness of this event was
due rather to changes of land use in the river basin and occupation of the floodplain.
According to the existing foronomic records, the peak discharge of the largest flood at
the Pulo do Lobo gauge station over a period of 42 years was that of 1947, with a flow
magnitude of 8,127 m 3 /s. This discharge is much smaller than the that of the floods recorded by
us. Also, from the SLW studied in the Tajo River, Benito et al (1998) considered that floods of a
similar or greater magnitude than the 1947AD flood have occurred at least nine times in the last
millennium. Historically, the largest flood for which height levels remain was that of 1876AD,
which devastated several towns and villages along the river basin. Recent estimations suggest
that the flood may have reached 10,600m 3 /s, which places it only in fourth to sixth place in the
range of floods studied.
According to our own findings, there have been at least two higher floods in relatively
recent times: probably those of 1758AD and 1603AD. The latter is the highest in the entire
sedimentary register that we have compiled throughout the studied reach, and these data are not
inconsistent with the conclusions reached previously in the historical record. In addition, there is
a very old record, of 3260BP, with a discharge of almost 12,000m 3 /s, which has been preserved
by the deposition of more recent levels. The data analysed need to be processed further and
compared with interpretations at other points in the basin where work is currently proceeding,
but the offer an example of how the analysis of floods and their return periods are in fact far
more complex than the simple statistical treatment of existing records on dates and water
heights. Such studies need to include preliminary analysis and individualisation of the type of
flood being handled in terms of their significance in the specific physical environment.
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of an extraordinary flood discharge estimate: Bronco Creek, Arizona”. Water Resources
Research, Vol. 31, Nº 12. 3059–3073 pp.
INM. (1998). “El Temporal de los días 5 y 6 de Noviembre de 1997”. Centro Meteorológico
Territorial de Extremadura. (Open File report). Badajoz.
MOYA, M. E.; GARZÓN, G. & ORTEGA, J. A. (1998). “Depósitos de la avenida del arroyo
Rivillas, Badajoz. Noviembre de 1997”. Investigaciones recientes de la geomorfología edited
by A. Gomez & S. Franch. Barcelona, 33-36 pp.
O´CONNOR, J. E. and WEBB, R. H. (1988). “Hydraulic modeling for paleoflood analysis”.
Flood Geomorphology, edited by V. R Baker.; R. C. Kochel., & P. C. Patton.,. Wiley
interscience. New York, 383–482 pp.
ORTEGA, J. A. & GARZÓN, G. (1997). “Inundaciones históricas en el Río Guadiana: Sus
implicaciones climáticas”. Cuaternario Ibérico, 365–367 pp. Huelva.
ORTEGA, J. A.; GARZÓN, G. & MOYA, M. E. (1998). “Parámetros climáticos y ambientales
de la avenida del río Rivillas”. Investigaciones recientes de la geomorfología española, edited
by A. Gomez & S. Franch, Barcelona, 237-246 pp.
TEMEZ, J. R. (1978). “Cálculo hidrometeorológico de caudales máximos en pequeñas cuencas
naturales”. MOPU., Madrid, 113 pp.
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 112-115
HISTORICAL FLOODS ANALYSIS BETWEEN THE ATLANTIC
AND THE MEDITERRANEAN WATERSHEDS IN CENTRAL-
POTENCIANO, A 1 AND GARZÓN, G. 2
1 Geological Institute (IGME), C/ Ríos Rosas 23, 28003 Madrid (Spain)
2 Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
Floods evolution since 1500 for the Tagus, Guadiana, Jucar and Segura Rivers basins
show an increase on flood occurrence from late 17th century till nowadays. Two main peaks
around 1890 and 1960 can be stated together with a widespread flooding decay at the begin of
both centuries, on the 1810´and 1920´ decades. The comparative floods analysis between
different river basins presents good correlation between floods peaks on the four studied basins,
but with some differences among them. In spite of the good clustering for flood periods, a
relationship with precipitation data of the different basins could not be been established clearly.
Historical floods on the Tagus, Guadiana, Jucar and Segura river basins have been
compiled, mainly from the data of Comisión Nacional de Protección Civil (1985), and
compared in order to point out differences between the Atlantic and Mediterranean watersheds
of the Southern Iberian Peninsula. A relationship between floods and long historical series of
precipitation, has also been established, in order to establish climatic relationships. The Atlantic
watershed is controlled by the frontal systems related to zonal circulation, whether the
Mediterranean one is mainly affected by Southern flows and cold pools (Capel Molina, 1981;
Olcina, 1994; Benito et al. 1996).
FLOODS COMPARISON BETWEEN ATLANTIC AND MEDITERRANEAN
The comparative floods analysis between different river basins (Fig. 1) shows a good
correlation between floods peaks on the four studied basins, but with some differences among
them. Floods evolution since 1500 shows an increase on the flood occurrence for all the studied
basins from late 18th century till the present one. Although this events increase might be
affected by a more rigorous registration, the recent development of structural regulation works
on the main rivers should also have smoothed the results.
On a further approach, the comparative analysis between Atlantic and Mediterranean
watersheds (Fig.2) confirms a same flooding trend for both. On the Atlantic divide, however,
since the middle of the present century, a significant flood increase is observed in respect to the
ones on the Mediterranean area (Martinez & Garzón, 1996; Ortega & Garzón, 1997). Two main
peaks around 1890 and 1960 (and a smaller on around1920) can be stated together with a
widespread flooding decay at the begin of both centuries, on the 1810´and 1910´ decades.
RELATIONSHIP OF PRECIPITATION AND FLOODS
In spite of the good clustering for flood periods, a relationship with precipitation data of
the different basins could not be been established clearly. This can be justified with a more
detailed approach to floods data on each basin, and on considering separately the floods of
different areas within the basin As en example, several populations can be considered for the
whole Guadiana basin: the ones from the upper basin, the coastal ones, and the ones from the
main river. On considering its yearly distribution, one can observe that the main river ones
mainly occur in winter, the upper basin ones are distributed preferentially in autumn, but also
during summer and spring, and that the coastal ones occur in winter, spring and fall (Potenciano
& Garzón, 2001).
Floods (Guadiana, Tajo, Segura and Júcar basin)
3 decades running average
Fig. 1. Historical floods and running average for the studied basins since 1500
1500 1600 1700 1800 1900
1500 1600 1700 1800 1900
Fig. 2. Comparison between floods on the Atlantic and Mediterranean watersheds
Considering this fact, a further approach has been realized in order to point out the
genetic significance for flooding trends between the different studied basins (Fig. 3). Floods at
the four basins have been considered in relation to its month of occurrence and the part of the
basin to which they correspond and compared to the historical precipitation. It can be stated that
for the Atlantic watershed during the last century floods were registered mainly in the upper
basins. On the other hand, during the last period, an increase in winter floods occurs for the
lower Atlantic basins. Jucar floods are quite homogeneous, whilst for the Segura basin a
significant decay can be noticed since middle of the present century.
DISCUSSION AND CONCLUSIONS
A cyclical flood recurrence can be stated with a remarkable increase since the last
century. Two main peaks are present, the most important one at the end of last century.
There is a good flood correlation on both Atlantic and Mediterranean watersheds , with
a decay of the Segura basin ones for recent years.
Two types of events have been identified, those originated by convective storms,
mainly during the fall months, and the ones controlled by Atlantic frontal systems, restricted to
This distribution reinforces the necessity of understanding the causes and mechanisms
of flooding when evaluating recurrence periods, more than a purely statistical approach.
BENITO, G.; MACHADO, M.J.; PÉREZ-GONZÁLEZ, A. (1996). “Climate change and flood
sensivity in Spain”. Ed. Branson, J., Brown, A.G. & Gregory, K.J. Global Continental Changes:
the context of Palaeohydrology. Londres. Geological Society Special Publication No.115 , 85-
CAPEL MOLINA (1981). “Los climas de España”. Oikos -Tau, Barcelona. 429 p.
COMISIÓN NACIONAL DE PROTECCIÓN CIVIL. (1985). “Estudio de inundaciones
históricas. Cuenca del Guadiana”. Tomo II. Madrid
MARTÍNEZ, J. & GARZÓN, G. (1996). “Análisis de las avenidas históricas en el río Júcar”. 6º
Congreso Nacional y Conferencia Internacional de Geología Ambiental y Ordenación del
Territorio. Volumen 3, 29-41 pp.
OLCINA, J. ( 1994). “Riesgos climáticos en la Península Ibérica”. Penthalon. 438 pp.
ORTEGA, J.A. & GARZÓN, G. (1997). “Inundaciones históricas en el Río Guadiana”. Ed.
Rodriguez, J. Cuaternario Ibérico. AEQUA. Huelva, 365-367 pp.
POTENCIANO, A. & GARZÓN, G. (2001). “Significado paleoclimático de las inundaciones
históricas en las cuencas fluviales atlánticas y mediterráneas del Centro–Sur de España”. 6º
Congreso Español de Geomorfología, Madrid. (en prensa)
DISTRIBUTION OF HISTORICAL FLOODS AND PRECI
G U AD IA N A , T A JO , S E G U R A A N D JÚ CAR RIVERS BAS
GUADIANA RIVER BASIN
GUADIANA UPPER BASIN FLOODS
GUADIANA LOW BASIN FLOODS
W INTER RAIN IN BADAJO Z
AUTUMNAL RAIN IN BADAJOZ
TAJO UPPER BASIN FLOODS
TAJO LOW BAS
TOTAL RAIN (mm)
TOTAL RAIN (mm)
SEGUARA RIVER BASIN
JÚCAR RIVER BASIN
W INTER R AIN IN ALIC ANTE
AUTUM NAL R AIN IN ALICANTE
TOTAL RAIN (mm)
TOTAL RAIN (mm)
Fig. 3. Historical floods and precipitation distribution according to the occurrence month and area of the basin
Groundwater and Landscape Sustainable Management. Ed. Department of Geodynamics (UCM), 2001. pp 116
MICROBIOLOGICAL STUDY OF THE INCRUSTATIONS AND
CORROSIONS IN GROUNDWATER WELLS
SENDEROS, A. 1 ; VILLARROYA, F. 1 AND De CASTRO, F. 2
1 Department of Geodynamics. Faculty of Geologic Sciences. Complutense University. 28040 Madrid (Spain)
2 Department of Microbiology, Faculty of Biology Sciences. Complutense University. 28040 Madrid (Spain)
A review is made to the mechanisms of the development of incrustations in
groundwater wells, doing special emphasis in the influence that the microorganisms can have in
this development, not only by the direct oxide and hydroxide of iron precipitation, consequence
of their own metabolism, but for the modification of the chemical parameters of the
surroundings or by "passive precipitation". Of most of the samples a shooting of the state of
each well has been made.
Due to the characteristics required by each water sample (sterility for the microbial
study and collection of incrustation at the same point), it has been necessary to design a specific
tool capable to be connected to the video camera. The tool has been patented with the record
number 990012081/1 of the Registry Office of Patents.
Chemical analyses have confirmed the variety of waters tried from the first moment. All
the samples have been imagined in specific diagrams of Pourbaix for the iron, being observed
that most of them falls within the field of stability of Fe(OH) 3 . The incrustations of Hematite and
Goethite predominate, although there are also deposits of the amorphous Fe(OH) 3 .
For the microbiological study, classic laboratory cultures have been made and a system
of detection by colorimetry patented by Dr. D. R. Cullimore of the University of Regina
(Canada) and that has first been used in Spain in this work. After the statistical analyses we
observe that the presence of certain types of micro-organisms is practically independent of the
characteristic of the well, so none is free to undergo alterations of this type. This confirms that
the periodic maintenance of the well is necessary, no matter is chemical characteristics and use.
Finally, there is a review to the most useful systems of regeneration of wells affected by
SENDEROS, A. (2001). "Estudio microbiológico de las incrustaciones y corrosiones en
captaciones de agua subterránea" Tesis doctoral inédita. Facultad de Ciencias Geológicas.
UCM. 281 pp más anexos. (Microbiological study of the incrustations and corrosions in
CULLIMORE, D.R. (1992). "Practical Manual of groundwater microbiology". Lewis Publish.
Michigan, 412 pp.