Hydrogeothermal Conditions in Ãire - Geological Survey of Ireland

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HYDROGEOTHERMAL CONDITIONSIN EIREC.R. Aldwell and D.J. BurdonIINTRODUCTIONThe paper attempts to bring together and present existing data onhydrogeological conditions in Ireland, with emphasis on the known warm springsof the country. It does not deal with the granites and other potentiallyhot dry rocks. The paper marks a preliminary stage in initiating the studyof the geothermal energy potential of the island.I-I.Scope and ObjectiveOn the "Atlas of Subsurface Temperatures in the European Community"(Haenel, editor, 1980), the Republic of Ireland is shown as a blank. Thoughsome temperature data has been obtained, it has not been published, exceptin very abbreviated form as in "Terrestial Heat Flow in Europe" (Cermak andRybach, editors, 1979).However, some data has been collected over the past 9 years on thewarm springs of Ireland, and there are also scattered records from the past.This paper endeavours to bring together such data, plus that obtained by theauthors, relating to the 17 known warm springs (including a very fewwarm boreholes) recorded in Ireland. The warm springs occur in ratherrestricted areas, as shown on Fig. 1; and no attempt has been made to studyor record hydrogeothermal conditions outside the areas of the known warmsprings. The field data collection was intensified towards the end of 1979,when almost all the known warm springs were sampled and their waters chemicallyanalysed under uniform conditions to produce comparable results.The establishment of a projectto make a preliminary investigationand assessment of the "Geothermal Energy Potential of Ireland" has givenadded impetus to the compilation of this present paper on hydrogeothermalconditions in Ireland. The 'Geothermal Project' is expected to receivethe support of the Commission of the European Communities (R. & D. EnergyProgramme), and to commence formally on I July, 1980. It is hoped thatthe collection and analysis of existing hydrogeothermal data made here willcontribute a little to the successful launching of this Project. As partof the Project, it is hoped to obtain a better understanding of thefunctions of known and still-to-be-discovered warm springs and boreholes,together with their potential for energy development and use. Low enthalpysources, such as the Irish warm springs, have potential in many fields,including horticulture, carp ponds, swL~ing pools, feed waters to industryand possibly space heating.1-2. Historic Warm SpringsThere are innumerable springs and spring wells in Ireland; theyare enshrined in place names, in myths and in legends. There are many holywells and springs, christianized sites of druidic worship and healing; theseusually bear the name of a saint. However, warm springs or wells are rare;the holy wells are not marked by any physical difference from ordinary wells.In the eighteenth and nineteenth centuries, there were many spas, of varyingreputation and importance; except for Mallow, their groundwaters were atnormal temperatures. At the still important spa of Lisdoorivarna, the watersare warmed prior to drinking
- 2 -Normal groundwater in Ireland varies from 9.5 0 to 10.5 0 C. Ittends to lie in the cooler range in the north, and possibly at higherelevations. Warm springs are considered as having appreciably highertemperatures than "normal", at least for a part of the year. Thus a springor well whose temperature was not reliably recorded as more than 12 0 C atsome time could not be called a warm spring or well; and plus 13 0 C would bea more normal lower temperature limit. Such a low-temperature "warm spring"would feel cool to cold in summer, and would only feel very slightly warmeven in winter. Hence, nmny slightly warm springs may well have escapednotice. It will be difficult to identify all Irish warm springs in the lowesttemperature range.The Mallow Spa spring is the oldest recorded warm spring in Ireland.Rutty (1957) states "Mallow-water was first discovered and introduced intopractice by Dr. Rogers of Cork about the year J724." Rutty also reports onthe "two tepid springs in the county of Dublin", at St. Margarets (No. 1009here) and Ballydowd (No. 1013 here, but not relocated on the ground). Twoof the main warm springs of Leinster were brought into operation by man'sactivities. Louisa Bridge spring (No. 1001) came into operation when theRoyal Canal was being constructed in 1794; Enfield spring became knownin the 1890s, when gravel was being excavated for a railway line. Untilquite recently, the number of warm springs recognised in Leinster were limitedto two or three. Grainger and Davies in 1966 state "Now, however, a thirdwarm spring has come to light in the region", referring to st. Gorman's(No. 1007), visited by Du Noyer on 21 July, 1859, but thereafter forgottenby investigators.In the 1970s however, attention began to be given to the warmsprings, in particular those of Leinster. Numerous temperature readingshave been collected by one of the authors since 1971. Enquiries were maderegarding hitherto unidentified warm springs. So, when Fahy, (1974, 1975)studied the biology of the Enfield spring (No. 1005) he was able to presenta map showing the location of 10 warm springs. Horne (1977) drew attentionto two warm springs in Munster, at Newcastle West (No. 2003) in Co. Limerick,and Hurler's Cross (No. 2004) in Co. Clare. Even as this paper was nearingcompletion news was received of a 'new' warm spring at Clonee, Co. Meath;this has been included in Table 1.So, by Spring 1980, it can be said that there are 17 warm springs(including boreholes) known in Ireland. They are listed in Table 1, withpositions indicated on Figs. 1 and 2. Dunlavin spring (No. 1012) isrejected; it could not be found on the ground when its reputed localitywas examined by one of the authors. Of the 17 accepted, 11 occur inCos. Dublin, Kildare and Meath, and are shown in some detail in Fig. 2; ifBallydowd (No. 1013) were relocated, it would fall within this area too.Further west in Leinster, there is Ballinalack (NO. 1011) spring or bore,reported by Prof. P. Br~ck, but not as yet examined by the authors. InMunster, there is the famous Spa at Mallow, issuing from a pool and in thewell constructed within the Spa House. Warm water was also encountered inthe borehole in the nearby Cattle Mart, and possibly in another bore (nowshut) close to the Spa itself. The warm springs at Newcastle West and atHurler's Cross have already been mentioned./ ...
Page 1 and 2: IIII1HXDROGEOTHERMAL CONDXTXONSIN E
Page 3 and 4: convection uprising of warm water i
Page 5: BallinalackNo .1011Hurler's .Cro~5N
Page 9 and 10: - 3 -Ref. No.Name or NamesCounty100
Page 11 and 12: - 5 -II-l. LocationThe general loca
Page 13 and 14: - 7 -Thickness(m)Lithology+ 335 m+
Page 15 and 16: - 9 -Boreholes drilled for water, p
Page 17 and 18: IIII.JJJ.S 0 .No-- --~--f-22C:1. -
Page 19 and 20: - 12 -iSpring No. 2001 2001 2002 20
Page 21 and 22: - FIGURE 5 - TRACE ELEMENTS SILICON
Page 23 and 24: - 14 -Spring No. 2001 2001 2002 200
Page 25 and 26: M'ddl~Slo9~CrySlol\'n~ bos.m.ntor d
Page 27 and 28: FIGURE 7 - POSSIBLE PRESENT~DAY GRO
Page 29 and 30: - 18 -The effects of the varying th
Page 31 and 32: - 20 -CLAYTON, G. and HIGGS, K. (19

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