Sustainability and SWM - Stavebná fakulta TUKE

LLP IP Erasmus No. 11203-1660/KOSICE03
Added value education in water management
Košice 12.6.2012
Ing. Zuzana Karelová
Technická Univerzita v Košiciach, Stavebná fakulta, Ústav budov a prostredia, Vysokoškolská 4, 042 00 Košice, zuzana.karelova@tuke.sk

INTRODUCTION
• Stormwater management is a process employing various non-structural and
structural measures to control stormwater runoff with respect to its quantity and
quality. (Marsalek and Chocat, 2002)
• Urban drainage systems can be divided into two most commonly used; combined
sewer system and separate sewer system.
• Combined sewer systems convey stormwater and waste water away in one pipe. Where
there are combined systems, there is a risk of combined sewer overflows (CSO) which
represents transfers of untreated waste water to receiving waters (Semadeni-Davies,
Bengtsson, 2000).
• Whereas separate sewer system carry stormwater and waste water in separate pipes,
usually laid side-by-side (Butler, Davies, 2011).
• Majority of drainage systems in Slovakia are combined. Nowadays we know that
this kind of system is economically and environmentally inefficient and in many
cases causes overloading sewerage systems and treatment plants as more frequent
floods prove it. It is essential that we introduce new sustainable approaches in
urban drainage systems in Slovakia as well.

STORMWATER MANAGEMENT (SWM) - influences
• There are at least two very important facts which need to be
considered when dealing with the SWM.
• It is increasingly changing climate, resulting in short term but more
intensive precipitation in one hand and increasing droughts in some
countries in the other.
• The second fact is increasing urbanization over the last years which has
changed the natural water processes and increased the urban runoff
significantly.
• These facts have influenced urban drainage and it is assumed
that they will influence it even more in the future.

SWM – past and present
• Pervious paradigms in SWM
• #1 Run It In Ditches
• #2 Run It In Pipes
• #3 Run It In Stormwater Pipes
• #4 Keep It From Stormwater Pipes
• #5 Well, Just Do Not Cause Flooding
• Future paradigms in SWM
• #6 Do Not Pollute
• #7 It Is The Ecology
• #8 Water Is Water Is Watershed
• #9 Green And Bear It
Source: (Debo and Reese, 2003)
• 10 basic contemporary SWM principles:
• 1. Managing stormwater as a resource;
• 2. Preserving and utilizing existing natural
features and systems;
• 3. Managing stormwater as close to the source
as possible;
• 4. Sustaining the hydrologic balance of surface
and ground water;
• 5. Disconnecting, decentralizing and
distributing sources and discharges;
• 6. Slowing runoff down, and not speeding it
up;
• 7. Preventing potential water quality and
quantity problems;
• 8. Minimizing problems that cannot be
avoided;
• 9. Integrating stormwater management into
the initial site design process
• 10. Inspecting and maintaining all BMPs.
Source: (Pennsylvania Stormwater BMPs, 2006)

SUSTAINABILITY IN SWM
• There are different names for more sustainable drainage mechanisms in different
countries:
• BMPs - Best Management Practices,
• SUDS - Sustainable Urban Drainage Systems,
• LID - Low impact development,
• Sustainable approach to urban drainage can be according to Stahre
divided into four parts of where we dispose stormwater:
• Source control
• Onsite control
• Slow transport
• Downstream control
Source Control
examples
Green roofs
Surface
percolation
Swale
percolation
Bioretention
Rainwater
Harvesting
Source: Stahre (2006)

RAINWATER HARVESTING (RWH)
• Rainwater harvesting is not only the part of source control measure in the
SWM, it is also the way
• how to control water consumption and
• how to support qualitative and reasonable water use for different purposes.
• One of the objectives of the Water Framework Directive is to promote sustainable
water use, based on long-term protection of available water resources and we
can say that RWH contributes to this objective.
• Rainwater could replace potable water in the following cases: flushing toilets,
maintenance and cleaning, irrigation, washing vehicles, process water or fire water.
• Before designing the system, it’s necessary to define the rainwater demand and
then determine storage capacity regarding effectiveness, reliability and total cost.

RAINWATER HARVESTING (RWH)
Rain and stormwater harvesting contribute to the integrated management of URBAN WATER CYCLE.
• It has direct impact on volume and quality of stormwater runoff ,
• reduction in flows to wastewater treatment plants (WWTP),
• and it of course conserves drinking water.
Source: (Scholes, 2007)
Table shows water
reuse matrix for
commercial purposes
Adapted from: (Guenter Hauber-Davidson )

RWH – examples
• Systems using alternative water sources are well known in many countries. There are
many case studies aimed not only at rainwater and storm water usage, they are
concerned in recycling and reuse e.g. of gray water and combined systems of rainwater
and gray water or respectively and its reliability and economic effectiveness as
performed Ghisi et al. (2007 a,b).
• Based on foreign case studies, it is possible to figure that household’s savings of potable
water could rise up to 60% for family houses and apartment houses. In the apartment
houses, water consumption increases in dependence on number of dwelling units and
surrounded areas needed to be irrigated. This particular case study is from Norrköping
in Sweden, where different alternatives of rainwater usage had also been considered.
(Villareal, Dixon, 2005)
• More and more case studies apply rainwater harvesting for other kinds of buildings
instead of residential buildings. Very interesting example is from the capital of Brazil,
where the usage of rainwater at petrol station for car washing could save from 7,4% to
57,2% of water. (Ghisi, 2009)
• Nowadays, the rainwater collection system is a common part of new architectural
designs of the buildings such as “The bird’s nest” (Beijing National Stadium), The
Millennium Dome in Greenwich London, Daimler Chrysler buildings in Berlin and sport
facilities for winter Olympic games 2010 in Vancouver. Most of the buildings use
harvested water for toilet flushing and irrigation.

QUESTIONNAIRE
Questionnaire, as one of data collection methods helps us to gather the essential information.
This questionnaire gives us closer look on people’s attitude to RWH and their water
consumption habits.
Number of respondents: 50
Number of questions: 26
Questionnaire performed on: spring 2010
Men/women: 34/66%
Age: 46% (20-30), 20% (31-40), 22% (41-50), 8% (51-60), 4% (61- )
100% - use potable water for all domestic purposes (toilet flushing including)
46 % - of the respondents have dual flash tank
The result is that most of our citizens are pro water saving oriented and open to new water
ideas.

RAINFALL AMOUNTS MEASURED AT THE TUKE CAMPUS
Rainfall amounts measured at the TUKE campus from April 2011 to December 2011 are shown
13,00
154,20
117,20
83,40
33,40 20,80 24,60 0,00
54,40
Data from TUKE campus
90,520 90,840
68,260
42,600
72,520
62,240
43,920
32,180 28,080
Average rainfall
2004 – 2009 (data
from: SHMÚ)

mm
2:15:00
2:50:00
3:25:00
4:00:00
4:35:00
5:10:00
5:45:00
6:20:00
6:55:00
7:30:00
8:05:00
8:40:00
9:15:00
9:50:00
10:25:00
11:00:00
11:35:00
12:10:00
12:45:00
13:20:00
13:55:00
14:30:00
15:05:00
15:40:00
RAINFALL AMOUNTS MEASURED AT THE TUKE CAMPUS
154,20
13,00
5,00
4,50
4,00
3,50
3,00
2,50
2,00
1,50
1,00
0,50
0,00
83,40
117,20
33,40
20,80 24,60
0,00
54,40
day
mm/day
02.07.11 10,80
04.07.11 0,40
05.07.11 7,20
06.07.11 7,20
08.07.11 2,40
11.07.11 13,60
12.07.11 0,20
18.07.11 0,20
19.07.11 0,40
20.07.11 7,20
21.07.11 20,00
22.07.11 8,20
24.07.11 3,40
25.07.11 14,00
26.07.11 19,20
27.07.11 9,80
28.07.11 5,00
29.07.11 3,20
30.07.11 16,80
31.07.11 5,00
hour

RAINWATER HARVESTING POTENTIAL
One of the ways how to promote sustainability in SWM is rainwater harvesting. It is
possible to use rainwater instead of potable water anywhere where there is no need for
such high quality water for example for flushing toilets, cleaning and maintenance, car
washing, irrigation, laundry etc.
The volume of rainwater depends on the area, rainfall, size of
the roof and the runoff coefficient. We can calculate it
according to the following formula
Q m = Ψ . A . Z M (m 3 /month)
Ψ – runoff coefficient ( - )
A – roof area ( m 2 )
Z M – monthly rainfall (mm/month = l/m 2 .month)
13,00
83,40
117,20
154,20
33,40 20,80 24,60 0,00
54,40
roof shape
flat
sloped
roof
covering
runoff
coefficie
nt
metal 0,7
asphalt 0,6
plastic 0,7
roof tile 0,8
concrete 0,8
slate 0,8
wood 0,75
metal 0,9
plastic 0,9
Source: Hlavínek a kol. (2007)
DIN 1989 Regenwassernutzungsanlagen,
precipitation measured at the university campus from April to
December 2011

RAINWATER HARVESTING POTENTIAL
Examples of potential volume of rainwater
in m 3 from the roofs of different sizes and
different runoff coefficients during July
2011 at the TUKE campus
ψ
roof area m 2
10 50 100 150
1,00 1,54 7,71 15,42 23,13
0,90 1,39 6,94 13,88 20,82
0,80 1,23 6,17 12,34 18,50
0,70 1,08 5,40 10,79 16,19
ψ
roof area m 2
200 250 300 350
1,00 30,84 38,55 46,26 53,97
0,90 27,76 34,70 41,63 48,57
0,80 24,67 30,84 37,01 43,18
0,70 21,59 26,99 32,38 37,78
ψ
roof area m 2
400 450 500 550
1,00 61,68 69,39 77,10 84,81
0,90 55,51 62,45 69,39 76,33
0,80 49,34 55,51 61,68 67,85
0,70 43,18 48,57 53,97 59,37
average water demand for:
flushing toilets
cleaning
washing
irrigation
flushing toilet - student
flushing toilet - employee
washing a car
washing a truck
washing a bus
amount
45 l/person.day
6 l/person. day
15 l/ person. day
60 l/m2.rok
6 l/ student. day
12 l/ employee. day
200 l/wash
700 l/wash
1000 l/wash
Source:
Hlavínek a kol. (2007),
DIN 1989 Regenwassernutzungsanlagen,
vyhláška 684/2006

SOURCES
• Marsalek, J. and Chocat, B. (2002), International Report: Stormwater management, Water Science and Technology Vol 46
No 6–7 pp 1–17
• Semadeni-Davies, A. and Bengtsson L. (2000), Theoretical Background, Chapter 1 in: Urban Drainage in Specific Climates,
Vol II. Urban Drainage in Cold Climate, IHP-V Technical Documents in Hydrology, No. 40, UNESCO, Paris
• Butler, D. and Davies, J. W. (2011), Urban Drainage, 3rd Edition, Spon Press an imprint of Taylor & Francis, ISBN 978-0-415-
45526-8
• Debo, T. N. and Reese , A. J. (2003), Municipal Stormwater Management, 2nd ed., CRC Press LLC, ISBN 1-56670-584-3
• Pennsylvania Stormwater Best Management Practices Manual (2006), Chapter 3, Stormwater Management Principles and
Recommended Control Guideline, online: http://www.elibrary.dep.state.pa.us/dsweb/Get/Version-
48474/04_Chapter_3.pdf
• Stahre, P. (2006), Sustainability in Urban Storm Drainage, Planning and examples, Svenskt Vatten, ISBN 91-85159-20-4
• The Water Framework Directive 2000/60/EC
• Guenter Hauber-Davidson Supplementing Urban Water SuppliesT hrough Industrial and Commercial Rainwater Harvesting
Schemes, http://www.watergroup.com.au/download/P_RWH-integrUrbWatSuplyGHDv1a070308.pdf
• Scholes, L. (2007), Stormwater reuse: why, how and where, SWITCH - presentation, online:
http://switchurbanwater.lboro.ac.uk/outputs/pdfs/WP2-1_PRS_Stormwater_reuse.pdf
• Ghisi, E., Ferreira, D. F. (2007 a), Potential for potable water savings by using rainwater and greywater in a multi-storey
residential building in southern Brazil, Building and Environment 42 (2007) 2512–2522
• Ghisi, E., Mengotti de Oliveira, S. (2007 b), Potential for potable water savings by combining the use of rainwater and
greywater in houses in southern Brazil, Building and Environment 42 (2007) 1731–1742
• Ghisi E, et al. (2009), Rainwater harvesting in petrol stations in Brasília: Potential for potable water savings and investment
feasibility analysis, Resources, Conservation and Recycling
• SHMÚ – Košice rainfall data from Slovak Hydrometeorological Institute
• Hlavínek P. a kol. (2007), Hospodaření s dešťovými vodami v urbanizovaném území, ARDEC s.r.o., ISBN 80-86020-55-X

Thank you for your attention