Wroclaw University of Environmental and Life Sciences Faculty of Environmental Engineering and Geodesy Landscape Architecture
Maria Pleśniak Indeks nr 67860
Ways of rainwater channelling in cities Master's thesis
Supervisor: dr hab. inż. Janusz Łomotowski
Wroclaw, September 2008
Uniwersytet Przyrodniczy we Wrocławiu Wydział Inżynierii Kształtowania Środowiska i Geodezji Kierunek Architektura Krajobrazu
Maria Pleśniak Nr indeksu 67860
Ways of rainwater channelling in cities (Sposoby odprowadzania wód deszczowych w miastach) Praca magisterska
Opiekun pracy: dr hab. inż. Janusz Łomotowski
Wrocław, Wrzesień 2008
Ways of rainwater channelling in cities
Maria Pleśniak
Oświadczenie opiekuna pracy Oświadczam, że niniejsza praca magisterska pt.: „Ways of rainwater channelling in cities” - autorstwa Marii Pleśniak została przygotowana pod moim kierunkiem w Instytucie
Architektury
Krajobrazu
i
stwierdzam,
że
spełnia
ona
warunki
do
przedstawienia jej w postępowaniu o nadanie tytułu zawodowego.
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podpis opiekuna pracy
Oświadczenie autora pracy Świadoma odpowiedzialności prawnej oświadczam, że niniejsza praca dyplomowa:
●
została napisana przez mnie samodzielnie i nie zawiera treści uzyskanych w sposób niezgodny z obowiązującymi przepisami USTAWY z dnia 4 lutego 1994r. o prawie autorskim i prawach pokrewnych
●
nie była wcześniej przedmiotem procedur związanych z ubieganiem się o tytuł naukowy lub zawodowy wyższej uczelni
●
załączona w wersji elektronicznej jest identyczna z wersją wydrukowaną.
............................................................................................. data
podpis autora pracy
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Ways of rainwater channelling in cities
Maria Pleśniak
Abstrakt
Sposoby odprowadzania wód deszczowych w miastach Streszczenie pracy Celem niniejszej pracy magisterskiej jest: – przedstawienie alternatywnych i jednocześnie zrównoważonych metod odprowadzania wód deszczowych w terenach zabudowanych w sposób przejrzysty – opisanie istniejących rozwiązań dotyczących zarządzania wodą opadową – zastosowanie zdobytej wiedzy do rozwiązania problemów wody deszczowej w konkretnym przypadku. Wraz z urbanizacją zwiększa się uszczelnienie powierzchni oraz ubicie gleby, w konsekwencji odpływ powierzchniowy i jego siła niszcząca. Jako udogodnienie i zabezpieczenie przed zalewaniem, erozją i zanieczyszczoną wodą został stworzony system odprowadzania wód deszczowych. Odprowadzanie wód deszczowych z terenów zabudowanych za pomocą podziemnych rur, do oczyszczalni lub wód powierzchniowych, jest metodą tradycyjną, która może podlegać przeciążeniu przy kontynuowaniu zabudowywania terenu. Pierwsza część pracy jest ilustracją wybranych zrównoważonych sposobów odprowadzania wód deszczowych (SUDS), które są alternatywne dla metod tradycyjnych. Ilustracja ma być zrozumiała dla wszystkich zainteresowanych, począwszy od profesjonalistów aż do właścicieli działek. W części drugiej zostały przedstawione i omówione, pod względem zrównoważonego rozwoju, dwa efektywne przykłady zarządzania wodą deszczową z Malmo w Szwecji. Zostały wysunięte następujące wnioski: istnieje potrzeba współpracy między różnymi dyscyplinami, takimi jak: firmy deweloperskie, planiści, inżynierowie zajmujący się systemami sanitarnymi, architekci, architekci krajobrazu, ekolodzy i hydrolodzy, etc. – potrzeba stworzenia klarownej i ujednoliconej terminologii a także zasad i wskazówek dotyczących zastosowania zrównoważonych systemów odprowadzania wód deszczowych (SUDS) dla problemów związanych z wodą deszczową oraz jej zanieczyszczeniem – zależnie od istniejących okoliczności, zarządzanie wodą opadową może obrać różne kierunki (kierunek środowiskowy-nakierowany na korzyści społeczności lokalnej, poprawienie jakości wody, redukcja ilości wody deszczowej) i w dalszym ciągu może być rozpatrywane jako zrównoważone. –
Trzecia część pracy jest praktycznym zastosowaniem wiedzy teoretycznej, zawartej w części opisowej (pierwszej i drugiej części pracy), do koncepcji projektowej zespolonego odprowadzania wód deszczowych dla działki domu jednorodzinnego. Celem rozwiązania jest zatrzymanie i rozprowadzenie wody w obrębie działki. Zaproponowane rozwiązanie, wdrożone w zwielokrotnieniu, w efektywny sposób łagodzi negatywne skutki uszczelnienia powierzchni i może być użyte przez władze samorządowe do promowania zrównoważonego zarządzania wodami opadowymi. Słowa kluczowe: odprowadzanie wód deszczowych, gospodarowanie wodą deszczową (zarządzanie wodą deszczową), SUDS - zrównoważone systemy odprowadzania wód deszczowych, zrównoważony rozwój, zespolone odprowadzanie wód deszczowych.
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Ways of rainwater channelling in cities
Maria Pleśniak
Spis treści 1. Cel, zakres i przedmiot opracowania
7
2. Metodyka
8
3. Woda opadowa a miasto
9
3.1. Miasto – warunki glebowe i wodne
9
3.2. Substancje szkodliwe i ich zachowanie w gruntach
11
3.3. Zrównoważony rozwój a zarządzanie wodą opadową
14
4. Wybrane sposoby redukcji, zatrzymywania, odprowadzania i podczyszczania wody deszczowej (przegląd literaturowy)
16
4.1. (A) Urządzenia do infiltracji wód deszczowych
17
4.1.1. Infiltracja bez retencji powierzchniowej
17
4.1.2. Infiltracja z gromadzeniem wody deszczowej na powierzchni
18
4.1.2.1. Niecka (także ogród deszczowy i obszar bioretencji)
18
4.1.2.2. Zbiornik
20
4.1.3. Infiltracja z z gromadzeniem wody deszczowej pod powierzchnią
21
4.1.3.1. Studnia chłonna
21
4.1.3.2. Rów chłonny
22
4.1.3.3. Rury drenarskie
23
4.2. (B) Urządzenia do zatrzymywania wód deszczowych (bez infiltracji)
23
4.2.1. Niecka filtracyjna z uszczelnionym dnem
24
4.2.2. Zbiornik retencyjno-filtracyjny
25
4.2.3. Dach z podpiętrzeniem wody deszczowej i zielony dach
26
4.3. (C) Urządzenia do podczyszczania wód deszczowych
27
4.3.1. Studnia osadowa
28
4.3.2. Studnia chłonna z osadnikiem
29
4.3.3. Worek filtracyjny z geowłókniny dla studni chłonnych
30
4.3.4. Pasaż roślinny
31
4.4. (D) Urządzenia do transferu wód deszczowych
32
4.5. (E) Inne urządzenia
33
5. Przykłady zespolonych rozwiązań odprowadzania wód deszczowych
34
5.1. Western Harbour (Bo01), Malmo, Szwecja
35
5.2. Augustenborg, Malmo, Szwecja
40
6. Wnioski
47
7. Koncepcja projektowa zespolonego odprowadzania wód deszczowych
49
7.1. Sytuacja istniejąca
49
7.2. Proponowane rozwiązanie
51
7.2.1. Elementy zespolonego odprowadzania wód deszczowych
52
7.2.2. Obliczenia
56
7.3. Podsumowanie
60
8. Bibliografia
62
9. Spis rycin, tabel i załączników
64
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Ways of rainwater channelling in cities
Maria Pleśniak
Abstract
Ways of rainwater channelling in cities Summary The aim of this thesis is to: – investigate alternative and sustainable ways of rainwater channelling in a clear way; – describe existing stormwater management solutions; – implement gained knowledge to case with rainwater difficulties. Together with the development the sealing and compaction of the surface increases. Consequently run-off and its destructive strength are growing. To make developed areas more convenient and protect them mainly from flooding, erosion and contaminated water drainage system was developed. Rainwater channelling via underground pipe systems to sewage treatment plants or watercourses is conventional method of draining surface water from built-up areas. The capacity of conventional drainage systems can be a constraint on development. First part of the thesis is an illustration of selected SUDS (Sustainable Urban Drainage Systems) that are alternative to the conventional stormwater channelling. Description is to be easy to understand for non-technical professionals as well for non-professional private lot owners. In second part two successful sites form Malmo, Sweden were described (using terminology from firs part) and discussed in context of sustainable rainwater management. Some conclusions are drawn: – there is need of collaboration of different disciplines as e.g.: developers, planners, drainage engineers, architects, landscape architects, ecologists and hydrologists, etc; – transparent and unified terminology as well as rules and guides of SUDS application when dealing with run-off contamination should be defined; – depending on existing circumstances rainwater management can be directed in many ways (amenity - benefit of the local community, water quality or water quantity) and still be considered as sustainable. Third part is a practical application of the theory from descriptive part of the thesis (first and second). It is conceptual design of 'rainwater chain' (combined elements that help to deal with rainfall) for plot with detached housing. The target of the project is to deal with water locally. Proposed solution applied in a multiple number in effective way can prevent negative results of surface sealing. It can be used by municipalities to promote sustainable stormwater management on the site. Keywords: rainwater channelling (stormwater channelling), stormwater management, SUDS – Sustainable Urban Drainage Systems, sustainability, stormwater chain.
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Ways of rainwater channelling in cities
Maria Pleśniak
Table of content 1. Introduction
7
2. Methods and materials
8
3. Stormwater and cities
9
3.1. City – soil and water conditions
9
3.2. Harmful substances and its treatment in soils
11
3.3. Sustainability and stormwater management
14
4. Selected ways of stormwater reduction, retention, conveyance and pretreatment (literature overview)
16
4.1. (A) Stormwater infiltration devices
17
4.1.1. Infiltration without retention volume
17
4.1.2. Infiltration with retention on the surface
18
4.1.2.1. Swale (also rain garden and bioretention area)
18
4.1.2.2. Pool
20
4.1.3. Infiltration with subsurface retention
21
4.1.3.1. Soakaway
21
4.1.3.2. Absorption ditch/trench
22
4.1.3.3. Drainage pipe (infiltration pipe)
23
4.2. (B) Stormwater retention devices (without infiltration)
23
4.2.1. Sealed filtration swale
24
4.2.2. Retention and filtration pool
25
4.2.3. Roof with clogging of water and green roof
26
4.3. (C) Stormwater pre-treatment devices
27
4.3.1. Sedimentation well
28
4.3.2. Soakaway with sedimentation tank
29
4.3.3. Geotextile filtration bag for soakaway
30
4.3.4. Vegetation passage
31
4.4. (D) Conveyance devices
32
4.5. (E) Other devices
33
5. Stormwater chain examples
34
5.1. Western Harbour (Bo01), Malmo, Sweden
35
5.2. Augustenborg, Malmo, Sweden
40
6. Conclusions
47
7. Stormwater chain concept project
49
7.1. Existing circumstances
49
7.2. Proposed solution
51
7.2.1. Stormwater chain composition
52
7.2.2. System sizing
56
7.3. Summary
60
8. Bibliography
62
9. Index of figures, tables and appendices
64
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Ways of rainwater channelling in cities
Maria Pleśniak
Acknowledgement
I wish to thank: dr hab. inż. Janusz Łomotowski for confidence, openness and patience; Marina Bergen Jensen, Natalia Mikołajczyk and Katarzyna Wieszczeczyńska for help with translation; my family and friends for support.
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Ways of rainwater channelling in cities
Maria Pleśniak
1. Introduction In the past rain was almost always seen as blessing. It was needed to water fields and animals. Stormwater, besides natural disasters, wasn't the difficulty until more modern times. Stormwater and wastewater became more problematic with increasing urbanisation. Various facilities were created and developed. Street gutters were already being built in antiquity, but puddles and stench were common. Later, an underground net of pipes, the sewage system, became an effective solution that has survived until the present. The problem of stormwater disappeared from view, but has it been solved once and for all? Today, we know that has not: municipal authorities complain about damages that flooding is causing after heavy rains; ecologists are warning about inefficient amount of clean water and inform us that big part of the not purified sewage contaminates rivers and lakes increasing its pollution. There is need of new, more sensitive solutions. There are many ways of stormwater channelling. Generally, it can be reduced by infiltration or evapotranspiration (rain gardens, previous pavements, drain pipes, lawns, swales), retained (green roofs, pools, containers), pre-cleaned and cleaned (surface sand filters, sedimentation wells, sewage treatment plants) or conveyed (gutters, channels, sewer system). To date, rainwater has mainly been redirected toward surface waters or sewage treatment plans. But with sustainable development there is tendency to change direction and use more and more sensitive solutions. They are very often combined in a ‘stormwater chain’. Combined system helps to reduce run-off locally (prevents flooding), improves water quality, local environment and also the ecological awareness of people. The objective of this thesis is to describe sustainable stormwater management solutions that are alternative or supplementary to the traditional stormwater management in sewer system. By describing sustainable urban drainage solutions (SUDS), presented as elements in a 'stormwater chain', is expected to be a clear and easy to understand way for non-technical professionals as well for non-professional private lot owners. Then this terminology is used to describe a number of solutions in Malmo, and further the position of the solution in sustainability is assessed. The conceptual stormwater management design fastens the thesis: from theory (SUDS description)
through
practice
(stormwater
management
in
Malmo)
until
implementation (conceptual stormwater design for plot). Application of SUDS in small scale is to be answer for rainwater issues that appears together with development.
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Ways of rainwater channelling in cities
Maria Pleśniak
2. Methods and materials Thesis contains three major parts: description of theory, description of implementation and design. First two relay on theoretic description of stormwater devices and comparison of two stormwater solutions in Malmo. The description of devices is made to be systematic and easy to understand. The terminology, after site survey, is applied to stormwater chain examples from Malmo. Then difficulties are clarified and some questions are posed. The case study (description part) serves to broaden the knowledge about stormwater management and is used in third part of the thesis - concept design made for plot having some rainwater problems.
Fig.2-1 Flow chart illustrating formation of this paper The thesis is based on literature survey (peer-reviewed publications, books, manuals, conference materials and web-sites), interviews (with designers, engineers, academics and habitants), sightseeing and inventory.
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Ways of rainwater channelling in cities
Maria Pleśniak
3. Stormwater and cities At the beginning of the 20th century with town expansion and industrialisation some epidemics broke out in European cities. It was discovered that it has a connection with a lack of stormwater channelling and sewage/waste purification. The chance was seen in the quick and joint channelling of (a) stormwater and (b) sewage from household and industry. The construction of the sewage system seemingly provided unlimited city and industry development.
3.1. City – soil and water conditions Geiger and Dreiseitl prove that there is close linkage between surface sealing and overflood. Surface sealing in the area of small rivers substantially raises flood wave, while quickened outflow in case of flood is difficult to get under control.
Flood as a result of urbanisation 1 Together with urban development sealing of the surface increases which changes proportions of the stormwater that evapotranspire, flow on the surface and infiltrate.
Fig.3-1 Proportions in stormwater distribution depending on sealing of the surface (level of the development) Generally, in cities transpiration and infiltration is smaller while velocity and surface flow is higher comparing to non-sealed, vegetation covered areas. Water capacity and evaporation of sealed surfaces is smaller, surface flow is bigger and quicker what may cause floods.
1
Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999
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Ways of rainwater channelling in cities
Maria Pleśniak
Fig.3-2 Infiltration, evapotranspiration and run-off have different proportions in natural areas and developed areas Impervious urban surfaces: 2 z
reduce natural evaporation
z
speed up stormwater run-off
z
cause soil erosion in landscaped areas and the banks of natural waterways
z
require
more
constructions
preventing
flooding
(drains,
culverts,
embankments). Dynamics of surface flow depend on location and slope of individual surfaces. Flow is higher
when
sealed
surfaces
are
bigger
and
connected.
However,
some
compensation may be achieved by small, sealed surfaces frequently changed with permeable ones. 3
Vegetation and surface run-off Impact of the vegetation on the surface run-off: z
enhance groundwater recharging through increased absorption
z
reduction of downstream flooding by elimination of surface water run-off
z
water quality improvement through filtering of dirty water and slowing of surface water velocity
z
increased infiltration and evapotranspiration.
Generally, vegetation is desirable to help to reduce surface run-off and prevent erosion. 4
2
3 4
A Green Vitruvius – Principles and Practice of Sustainable Architectural Design, James & James, London 1999 Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999 A Green Vitruvius – Principles and Practice of Sustainable Architectural Design, James & James, London 1999
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Ways of rainwater channelling in cities
Maria Pleśniak
3.2. Harmful substances and its treatment in soils As water from rainfall and snowmelt flows through the landscape, it picks up and carries contaminants from many different sources. This polluted water ends up in streams, lakes and the ocean by flowing directly in or by going through untreated storm drains. Water also carries pollutants into the underground drinking water as it soaks into the ground.
Pollution of urban run-off The urban run-off washes pollutants from streets, parking lots, construction sites, industrial storage yards and lawns. Besides “conventional” pollutants like sediments, nutrients, oxygen demanding materials and bacteria found in both urban and rural run-off also toxic pollutants as metals, pesticides and other chemicals can be detected. “Conventional” pollutants z
Sediments
Mix of sediments produced by urban areas — flakes of metal from rusting vehicles, particles from vehicle exhaust, bits of tires and brake linings, chunks of pavement, and soot from residential chimneys and industrial smokestacks. The leading sources of sediment in existing urban areas are industrial sites, commercial development and highways. z
Nutrients
Run-off from urban areas as well as from rural is loaded with nutrients such as phosphorus and nitrogen. Phosphorus is the nutrient of greatest concern because it promotes weed and algae growth in lakes and streams. z
Oxygen Demanding Materials
Urban run-off carries organic material such as pet waste, leaves, grass clippings and litter. Run-off from older residential areas (with more pavement, more pets, and combined storm and sanitary sewers) carries the highest load of oxygen demanding materials. z
Bacteria
Sources of bacteria in urban run-off include sanitary sewer overflows, pets, and populations of urban wildlife such as pigeons, geese.
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Ways of rainwater channelling in cities
Maria Pleśniak
Toxic Pollutants z
Metals (mainly lead and zinc)
Lead is a problem for both humans (damage to the nervous system and kidneys, high blood pressure and digestive disorders) and aquatic life (toxic). Zinc does not create human health problems, but it can be toxic to an aquatic life. The primary source of many metals in urban run-off is vehicle traffic. Concentrations of zinc, cadmium, chromium and lead appear to be directly correlated with the volume of traffic on streets that drain into a storm sewer system. z
Pesticides and herbicides
Tests indicate that most properly applied pesticides are bound up in plants and soil; therefore, little runs off. Nevertheless, some pesticides are frequently found in urban run-off at levels that violate water quality standards. Finding agricultural herbicides in urban stormwater may seem surprising since they are not used in lawns and garden compounds. However, the herbicides in urban runoff are consistent with concentrations found in rainfall. It turns that those chemicals easily evaporate from treated farm fields and later end up in rainfall or snow. z
Other Chemicals
There are many other potentially toxic chemicals found in urban run-off. Some of these chemicals are hazardous even in very small doses and require water quality standards set to parts per billion. Sampling for these chemicals can be difficult and costly so information on them is very limited. Some of them are products of incomplete combustion from vehicles, wood and oil burning furnaces, and incinerators. Some are used as ingredients in gasoline, asphalt and wood preservatives, insulation in transformers and in electrical capacitors for old fluorescent light fixtures and appliances, coolants or lubricants, they might be present in sediment contaminated by past industrial waste discharges, spills, and waste incineration. They remain in the environment for a long time, build up in the food chain, accumulate in human fatty tissue, and may eventually cause health problems (cancer, skin sores, reproduction problems, foetal abnormality development, immunity to disease, and problems with liver functions). 5
5
Miffin W., Polluted urban runoff, 1997
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Ways of rainwater channelling in cities
Maria Pleśniak
Soil as a filter, buffer and converter In case of transportation of harmful substances by stormwater soil works as a filter. When infiltration is slower there is better water purification (water movement through smaller pores allows soluble substances or sediments to attach to soil particles). But with faster infiltration substances contained by water may be transferred deeper. 6
Fig.3-3 Treatment of harmful substances in soil (mechanical, physiochemical and microbiological processes) Mechanical filtration is that suspension of harmful substances are bonded or retained in soil. In upper parts of the soil filtration or buffering (physiochemical processes) of organic harmful substances that evaporate or heavy metals occurs. In humus layer where the best conditions for micro-organisms are there is the highest conversion of contaminants. Also some water-soluble substances are removed from soil when absorbed by vegetation.
6
Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999
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Ways of rainwater channelling in cities
Maria Pleśniak
3.3. Sustainability and stormwater management Sustainability Up to 1987 (the Brundtland Commission, formally the World Commission on Environment and Development) the global development was seen as two dimensional. In 1987, to the economic and social, environmental (third contribution) was added and a sustainable development was defined.
Fig.3-4 Global Development up to 1987, Global Development after 1987 The sustainability was specified as a development that meets the needs of the present without compromising the ability of future generations to meet their own needs. 7
Sustainable stormwater management Sustainable Drainage Systems (SuDS), also known as Sustainable Urban Drainage Systems (SUDS), are solutions that reduce potential adverse impact of the development on disturbed there water. The idea behind SUDS is to collect, store, clean, allow to evapotranspire or infiltrate and drain away surface water by replicating natural systems (i.e. reed beds, constructed wetlands, etc.) before allowing it to be released slowly back into water courses. SUDS prevent flooding and sewer flooding on the development site, release sewage system and also protect and enhance water quality.
7
Edwards B., Hyett P., Rough Guide To Sustainability, RIBA Publications, London 2002
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Ways of rainwater channelling in cities
Maria Pleśniak
Fig.3-5 SUDS deal in an integrated way with issues of water quantity, water quality and amenity 8 There are some principles how to return excess surface water to the natural water cycle with minimal harmful effect on the environment and people: ●
manage the stormwater that runs off on site as close to the source as possible
●
slow down the velocity of the run-off
●
treat polluted water using natural processes; and
●
release to the watercourse and the groundwater water that has good quality.
SUDS are to be easy to manage, cost effective, flexible to use, environmentally and aesthetically friendly and require little or no energy input (except from environmental sources such as sunlight, etc.). To achieve the goal of SUDS there is necessity of working in partnership by numerous disciplines and agencies (developers, planners, engineers, architects, landscape architects, ecologists and hydrologists). 9 To work in cooperation there is necessity to create universal and easy way of presenting SUDS and inform/educate about it.
The term SUDS was described in United Kingdom, however the United States has developed their own approach and own terminology such as Best Management Practice (BMP) and Low Impact Development (LID). 10
8 Term explanation: ‘In the contexts of real estate and lodging, amenities are any tangible or intangible benefits of a property, especially those which increase the attractiveness or value of the property or which contribute to its comfort or convenience.
Tangible amenities might include parks, swimming pools, health club facilities, party rooms, bike paths, community centres, doormen, or garages, for example. Intangible benefits might include a "pleasant view" or aspect, low crime rates, or a "sun-lit living room", which all add to the living comforts of the property.’ (http://en.wikipedia.org/wiki/Amenity) 9 Sustainable Urban Drainage Systems, http://www.scotland.gov.uk/Publications/2001/07/pan61, accessed: V 2008 http://en.wikipedia.org/wiki/Sustainable_urban_drainage_systems, accessed: V 2008 10 Sustainable Urban Drainage Systems, http://www.scotland.gov.uk/Publications/2001/07/pan61, accessed: V 2008
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Ways of rainwater channelling in cities
Maria Pleśniak
4. Selected ways of stormwater reduction, retention, conveyance and pre-treatment (literature overview) 11 Any technique that soaks water into the ground makes water available for evapotranspiration, stores water for re-use or diverts stormwater away from the drainage system can be considered as a volume reduction practise: ●
infiltration - process of soaking water into the ground
●
evapotranspiration - combined process of evaporation and transpiration
●
retention – water storage
●
conveyance - process prolonging water transportation time, sometimes allowing transpiration or water soaking into the ground.
SUDS besides run-off reduction are to treat water against its quality worsen. This part of the thesis is to be organised and easy to understand (for non-technical professionals as well for non-professional private lot owners) description of exemplary SUDS that uses simple techniques and are relatively simple to apply. Devices were divided into those that allow infiltration, retention, those that pre-treat rainwater and those that allow conveying it. Despite of attempt to make the division clear some that have many functions (e.g. infiltration and conveyance like swales) were difficult to assign to only one group. In this case the main purposes were chosen to organise SUDS.
11
Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999
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Ways of rainwater channelling in cities
Maria Pleśniak
4.1. (A) Stormwater infiltration devices 12 4.1.1. Infiltration without retention volume Principle Stormwater is allowed to seep into the soil through permeable or vegetated surface. There is no room for temporary holding back of water (retention). Ability to purify water Very good on the top level of a surface covered with grass and when slowly soaking away through fine-grained top layers. Maintenance Normal maintenance of the grass (regular moving) and other plants. Possible applications • areas with high or average permeability • roads (in parks, in residential areas, fire roads), courtyards, squares, sports grounds Advantages • good conditions for maintenance • high ability to purify water (water quality doesn't have to be high)
Disadvantages • small retention possibility • demand of a big surface
Combination and variation possibilities • with retention and treating devices • overflow to swale, drainage pipe or ditch where efficiency of infiltration is insufficient Possible sorts: • without vegetation (mineral foundation, drainage asphalt, concrete grate, permeable arrangement of paved surface) • with vegetation: grass or other plants (grassy rubble, openwork gratings with grass, lawns) Tips • •
the absorption capacity has to be bigger than the expected rainwater flow inflow to whole surface should be evenly distributed Fig.4-1 Permeable parking lot allows water to infiltrate on the site
Fig.4-2 – 4-6 Examples of surfaces (vegetated, not vegetated, strengthened and not strengthened) that allow infiltration on the site 12
Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999
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4.1.2. Infiltration with retention on the surface Two possibilities of infiltration with retention on the surface are described: in swales and pools. In general, the difference is in time of storing the rainwater.
4.1.2.1. Swale (also rain garden and bioretention area) Principle Surface infiltration through humic soil surface and fine grained top layers. Used in open, green areas with possibility of temporarily holding the stormwater. Ability to purify water • high biological purification in a well-structured soil layer covered with vegetation • retention of insoluble substances Maintenance • regular maintenance and control (especially in autumn after leaves have fallen) • regular moving demanded • surface smoothing away when needed Possible applications • areas with average permeability • in order to develop or improve housing surroundings • green areas, road sides Disadvantages Advantages • may accumulate rubbish or • high ability to purify water (water quality doesn't have to be high) organic waste • requires space • high retention • good conditions for adaptation in green areas • possible to use as a garden element if cover with various vegetation • good conditions for maintenance Combination and variation possibilities • with belowground storage (infiltration trench) • upstream retention or pre-treatment devices Tips • • •
stormwater should be retained no longer than 1-2 days (longer period may cause surface sealing of the soil and consequently block the infiltration) avoid surface sealing and compaction during construction (e.g. heavy machinery) the bottom must be even or cascade shaped
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Fig.4-7 Cross-section of a rain garden/bioretention area
Fig.4-8 Rain garden with perennials (evaporation of perennials is big because of its fast growing as contrasted with threes and shrubs); Fig.4-9 Grass swale in Augustenborg, Malmo has double task: transportation and on-lot infiltration; Fig.4-10 This linear rain garden at campus of University of California in Merced, USA is beautifully incorporated in the landscape
Fig.4-11, 4-12 Bioretention area at University of Illinois at Urbana-Champaign, USA adds specific character to the area and looks attractive with water and also without (4-11 shows spring set, 4-12 shows autumn set)
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4.1.2.2. Pool Principle Water infiltrates through humic soil surface and top fine grained layers of the soil. The water capacity is higher and the water can be retained for a longer period than in swales. Ability • • •
to purify water good biological purification in humic layer of a soil retention of insoluble substances higher purification efficiency if formed sedimentation layer is kept
Maintenance • regular maintenance and control (especially in autumn after leaves have fallen) • regular greenery maintenance • removal of sediment when the infiltration is blocked Possible applications • mainly used for motorways drainage • for bigger drainage (> 1ha) • areas (existing or new developments) with efficient surface area Advantages • high ability for purification (water quality doesn't have to be high) • good conditions for water storage • good conditions for adaptation in the landscape (as a biotop) • good conditions for maintenance
Disadvantages • dangerous for children when filled up (fence may be needed) • self-blocking if wrongly maintained • if sediment is not removed toxic concentrations may build up (conflict with biotope ambition)
Combination and variation possibilities • upstream retention or pre-treatment devices • with swales Tips • • •
vegetated bottom and banks increase infiltration rate avoid surface sealing (e.g. by building trucks) to avoid bank erosion use boulders at the water inflow
Fig.4-13 Cross-section of an infiltration pool
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4.1.3. Infiltration with subsurface retention Infiltration with subsurface retention allows water to be stored under the ground (e.g. in soakaways, pipes and ditches). It is applied to sites without sufficient space to store water on the surface.
4.1.3.1. Soakaway Principle Concentrated below-ground spot from where stormwater soaks into the soil through artificial filtration layers. There is direct infiltration into groundwater and no possibility to soak through fine grained top soil layers. Ability to purify water • poor condition for water purification, water has to be pre-treated • retention of larger insoluble substances Maintenance • regular control • removal of clocking layers of sediment Possible applications • when soil permeability is good and average • inside cities and where available space is limited Advantages • small surface demand • good controlling possibility • application possible even where there are impermeable top layers
Disadvantages • no possibility to water purification • limited maintenance possibility • water shouldn't contain fine suspensions or other pollutants • high reconstruction costs when blocked
Combination and variation possibilities • upstream retention or pre-treatment devices • combined with swales and drainage pipes
Fig.4-14 Soakaway cross-section;
Fig.4-15 Soakaway inflow hidden in stones
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4.1.3.2. Absorption ditch/trench Principle Soaking away under the ground by artificially inserted gravel with good permeability, big infiltration surface and high retention capacity. Ability to water purification • very small if not constructed with surface infiltration (then pre-treatment devices are required) and when soaking away omit top fine-grained layers (good only through top layers if soil is covered with vegetation) Maintenance • no maintenance possibility, replacement necessary Possible applications • grounds with average permeability • when drilling of less permeable layer is needed in order to reach more permeable one Advantages • small surface demand • good retention capacity • small restrictions in surface use
Disadvantages • poor conditions for water purification • water shouldn't contain suspensions or other pollutants • no maintenance possibility
Combination and variation possibilities • possible location: just below the surface or deeper • different shapes possible: linear, wavy, bended, network • with swale (for better retention capacity and better water purification ability) • upstream retention or pre-treatment devices • additional infiltration might be provided by top fine-grained layers
Fig.4-16 Cross-section of absorption ditches with (a) point inflow and (b) surface inflow; Fig.4-17 Construction of an absorption ditch
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4.1.3.3. Drainage pipe (infiltration pipe) Principle Perforated drainage pipes in covered ditches provide linear infiltration. Pipes and wrapping gravel assure retention capacity. Ability to water purification • no possibility for water purification, pre-treatment devices are needed Maintenance • conditionally allowed rinsing of pipes Possible applications • grounds with average permeability • possibility to omit higher non permeable layers Advantages • small surface demand • good retention capacity • small restrictions in surface use • light constructions on the surface are possible (e.g. a garage)
Disadvantages • no possibility for water purification • low maintenance and conservation possibility ●
water shouldn’t contain suspensions or other pollutants combination
4.2. (B) Stormwater retention devices (without infiltration) 13 Stormwater retention devices serve to retain water without allowing it to infiltrate to the ground. These kinds of devices are used to:
13
•
slow down rainwater run-off
•
retain stormwater before its infiltration, control, treatment or channelling.
Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999
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4.2.1. Sealed filtration swale Principle Sealed, drained swale with good retention and water purification functions. Water is carried away to a natural receiving water body, or an infiltration device. Ability to purify water • high biological purification in a living layer of a soil • holds back dissolved substances Maintenance • regular greenery maintenance Possible applications • application independently from soil permeability and contamination • for pre-treatment of heavier contaminated water • near roads with high traffic volume Advantages Disadvantages • optimum control possibility before • lack of percolation (volume water is soaking away or discharged reduction) • good retention properties • may accumulate rubbish or organic waste • good conditions for adaptation in green areas Combination and variation possibilities • downstream soaking away devices, pre-treatment devices or vegetation passages
Fig.4-18 Cross-section of a grass filtration swale; Fig.4-19 Cross-section of a vegetated swale with sealed bottom
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4.2.2. Retention and filtration pool Principle Sealed, drained pool with humus surface and light liquid (oily substances) separator added. Ability to purify water • high biological purification in humic layer of the soil • holds soluble substances Maintenance • regular greenery maintenance Possible applications • only for bigger drainage basins (>1ha) • for pre-treatment of heavier contaminated water • near roads with high traffic volume Advantages • optimum control possibility before water is infiltrated or discharged • good water purification ability • good water storage ability (backwater) • possibility to create shape of natural pond
Disadvantages • dangerous for children when filled up (fence may be needed) • lack of percolation (volume reduction)
Fig.4-20 Cross-section of a retention and filtration pool;
Fig.4-21 Retention pool in
Augustenborg, Malmo attracts people (sitting place close to the water)
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4.2.3. Roof with clogging of water and green roof Principle Stormwater retention in vegetated and porous ground foundation or water clogging (backwater). Delayed run-off and run-off reduction by evaporation. Ability to purify water roof with clogging of waters • no possibility for water purification green roof • biological and mechanical rainwater purification by filtration through vegetation and porous ground medium Maintenance roof with clogging of waters • regular water outlet controlling green roof • maintenance during first 2-3 years (water outlet rinsing if blocked, vegetation maintenance) • with intensive vegetation watering and maintenance is needed Possible applications • on every flat roof • on sloping roofs, with slopes up to 30*. At higher slopes plants are possible only with protection • good efficiency in dense urban areas Advantages Disadvantages roof with clogging of waters roof with clogging of waters • good retention efficiency • higher roof load • often small costs of flat roof • higher leakproofness requirement reconstruction (choke and overflow installation) green roof green roof • good retention efficiency • higher roof load • air contamination reduction, air • higher leakproofness requirement enrichment in oxygen and local • high maintenance needed with microclimate improvement intensive vegetation • increased wildlife (promotes diversity of plants, insects and birds) • noise suppression • temperature regulation under the roof • lengthening of the life expectancy of the roof • improvement in the appearance of the rooftops • good adaptation possibilities in the landscape
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Combination and variation possibilities roof with clogging of waters • with infiltration devices
Fig.4-22 Roof with clogging of water
Maria Pleśniak
Combination and variation possibilities green roof • with infiltration devices • with stormwater reusing
Fig.4-23 Green roof
Fig.4-24, 4-25 Green roofs are not a new invention; Pictures show 18th century farm from Sweden (Open Air Museum in Copenhagen)
4.3. (C) Stormwater pre-treatment devices 14 In this chapter stormwater pre-treatment devices base on basic processes as: sedimentation, filtration, sediments and oil separation are presented.
14
Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999
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4.3.1. Sedimentation well Principle Intermediate stormwater storage and mechanical purification by sedimentation in concrete well (with bottom). Ability • • •
to purify water purification by sedimentation light and floating substances holding by dipped wall dissolution and washing out of sediment particles
Maintenance • regular removal of sediments • controlling twice a year Possible applications • stormwater pre-treatment with high level of sediments • small stormwater inflow Advantages • small surface demand • no or small restrictions in surface usage
Disadvantages • ability to purification limited to substances that sediment easily
Combination and variation possibilities • downstream soaking away • pre- treatment devices
Fig.4-26 Cross-section of a sedimentation well
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4.3.2. Soakaway with sedimentation tank Principle Combined infiltration and sedimentation chamber).
sedimentary
well.
Low
part
is
leakproof
(creating
Ability to purify water • purification by sedimentation • sediment outflow reduction by usage of geotextile Maintenance • yearly removal of sediments • controlling four times a year Possible applications • stormwater pre-treatment with high level of sediments Advantages • small surface needed • no or small restrictions in surface usage • possibility to omit higher non permeable layers • small construction costs
Disadvantages • small maintenance possibility • purification ability limited to substances that sediment easily
Combination and variation possibilities • upstream: retention or other treatment devices
Fig.4-27 Cross-section of a soakaway with sedimentation tank
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4.3.3. Geotextile filtration bag for soakaway Principle Geotextile in form of a bag fitting a well, typically used in a road. Water purification by filtration through geotextile. Ability to water purification • high sediments holding (also dust and clay) Maintenance • first cleaning after a year, later every second year (bag rinsing) • controlling four times a year Possible applications • pre-treatment for water with dominant insoluble substances • in cities - small surface needed Advantages • higher purification ability than for soakaway with sedimentation tank • very small surface needed Combination and variation possibilities • downstream retention devices and treatment devices
Fig.4-28 Removal of sediments from the bag
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4.3.4. Vegetation passage Principle Sealed bottom allows rainwater to flow through soil and roots. Ability • • • •
to water purification high ability to purify water by oxygen and oxygen-free decomposition mechanical purification chemical and physical (adsorption) bond on soil particles biological ability to purify is 20% lower in winter
Maintenance • maintenance of vegetation • yearly vegetation cutting, at the latest in the spring • regular controlling of inflow and outflow Possible applications • more advanced stormwater purification with high biological contamination • in cities as a biotope Advantages • high ability to remove soluble biological substances • good controlling possibilities • good adaptation possibilities • lack of objectionable odour enable to use it residential areas
Disadvantages • maximum efficiency only with constant inflow • rainwater shouldn't contain insoluble substances • big surface demand
Combination and variation possibilities • recommendation to connect to precedent retention and mechanical treatment devices • succeeding by infiltration devices Tips • • • •
water level should be always below the surface to avoid water bypassing above the surface upstream sedimentation device to clean from suspended impurities use gravel to suppress water hammer avoid soil consolidation
Fig.4-29, 4-30 Vegetation passage cross-section and an example of vegetation passage
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4.4. (D) Conveyance devices Principle Conveyance devices are to transfer rainwater from one place to another. Ability to purify water Depends on used materials and construction. Variation possibilities: (a) open and closed channels (b) gutters (c) drainpipes (d) swales (see 4.1.2.1) (e) sealed filtration swales (see 4.2.1) Possible sorts: • underground • on the surface: in sustainable rainwater it is to make rainwater management visible as educational and attractive, and also to reduce costs of its construction (but it also depends on used material) • •
permeable: e.g. (d) – with gravel , grass or vegetation with sealed bottom: e.g. (e)
• •
monofunctional: e.g. (a), (b), (c) - conveyance multifunctional: e.g. (d) – water infiltration and purification, transport
Tips • •
the capacity has to be bigger than the expected rainwater flow (proper dimensions) conveyance devices on the surface should be visually attractive when applied in dwelling areas and public spaces
Fig.4-31 – 4-34 Channels examples; Fig.4-31 Rainwater is channelled away from building; Fig.4-32 Threshold in form of a stream acting as a bump (slowing traffic speed); Fig.4-33 Semi open channel to the stormwater planter; Fig.4-34 Open channel changing into closed (under pavement) to allow easy pedestrian traffic
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Fig. 4-35 – 4-37 Gutters in form of a chain leading water from the roof to the ground
4.5. (E) Other devices Other devices are devices that not arranged in lists above or having different purposes. They are small scale solutions, usually additional for conveyance and storage. Principle To slow down velocity of water, clean rainwater, etc. Ability to purify water depends on variation. Variation possibilities: (a) pipe’s ends (e.g. Fig.5-21, 5-22, 5-23, 5-49) (b) thresholds (e.g. Fig.5-17, 5-18, 5-19, 5-20, 5-54, 5-55) (c) stones (e.g. Fig.5-50, 5-51) (d) cubes (e.g. Fig.5-52, 5-53) (f) etc. Tips • •
the capacity has to be bigger than the expected rainwater flow (proper dimensions) conveyance devices on the surface should be visually attractive when applied in dwelling areas and public spaces
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5. Stormwater chain examples Stormwater chain it is a bigger system that combines different stormwater management elements. Combination can multiply beneficial effects of reducing the run-off, what is the major objective of SUDS. Stormwater solution design should be followed with the site analysis focused on looking for possibility of developing linked elements that complement each other and prevent the site in an efficient way.
Fig.5-1 Stormwater chain example consisting of various devices that reduce run-off by delaying it, storing and infiltrating As stormwater chain examples two sites from Malmo, Sweden were selected. Then volume reduction techniques were defined, described (in systematic way using terminology from chapter 3) and discussed to show the main purpose of the solution and how it fits in sustainable stormwater management.
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5.1. Western Harbour (Bo01), Malmo, Sweden
Fig.5-2 Bo01 development plan In Western Harbour (Vastra Hamnen) on previous harbour, shipyard and industrial are the new housing estate (Bo01) is developing. The first stage was built and completed for the European Housing expo 2001 as the ‘City of tomorrow’. The aim was to make the Western Harbour an internationally leading example of a densely populated, environmentally sound neighbourhood. Houses are built close together – the ecological and sustainable society has to use valuable ground space efficiently. Pedestrians and bicycles have priority (Bo01 is car free). The area gets its energy supply from renewable sources; solar energy and wind power. Some IT-solutions are implemented for reading meters and controlling of energy use and ventilation in dwellings. Water is feature in various forms: (a) salt water in the open sea, in the harbour and in the canal, (b) fresh water in a system of ponds and miniature canals. The water from the sea is pumped to the canal and tap water runs trough retention ponds. Run-off is controlled locally. Rainwater is delayed on green roofs and in retention pools located in courtyards and public spaces. It runs through open paving channels which discharge via the ornamental canal into the sea. There is no water harvesting for washing.
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Visible waterways combined with trees and undergrowth (a symbol of life and ecology of the district) provide good qualities to this rather sterile urban environment.15
16
Fig.5-3, 5-4 The amenity aspect is maintained by numerous works of art (sculptures, fountains) spread around the area; pictures show autumn and summer set of one of art works
A.
Western Harbour - Bo01 C. D. Type of device Retention PreConveyance treatment 1. pools (canal 1. open and along the park closed channels and pools with vegetation) 2. gutters 2. green roofs B.
Infiltration 1. permeable surfaces
E. Other 1. pipe's ends, thresholds
Tab.5-1 Type of devices and its major contribution in the stormwater chain; conveyance and retention are the most significant in the area
Fig.5-5 Cross section of stormwater chain (marks are reflections of marks from the table) 15 16
http://www.greenroof.se http://www.eco-guide.net
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A1. Permeable surfaces Besides parks and courtyards there is lack of permeable surfaces. The area is densely build and paved between buildings to provide access to them.
Fig.5-6 Grid of green areas and green roofs
B1. Pools Retention pools in Bo01 are in form of (a) pools with vegetation and a large, 1 meter deep (b) canal along the ‘Ankarparken’ park.
Fig.5-7 - 5-9 Pools with vegetation (a) are located on public squares and along the main walking paths; supply with water is provided by rainwater and tap water running through it
Fig.5-10 - 5-12 Pools with vegetation (a) are raised to avoid melting of salted water from the canal (b) with sweet water form pools; as we can see on the pictures pools have high aesthetical values during vegetation season
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Fig.5.13 The sea water is pumped into the canal to keep it wet and attractive
B2. Green roofs Low maintenance green roofs are usually covered with ‘Sedum’. It is able to cope with extreme drought and at the same time to soak up huge amount of rainwater while growing on very thin earth layer (5cm, including drainage layer). Fig.5-14 ‘Sedum’ gives reddish colour to the ‘roof landscape’
D1. Open and closed channels Channels have various shapes (rounded, cubic and trapezoid) and depth. They lead water to through retention ponds to the canal or sea.
Fig.5-15 Cross sections of channels [m]
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Fig.5-16 However, some channels seem to be only a dummy going up the slope (as we can see on the picture)
E1. Pipe’s ends and thresholds Pipe’s ends are attractive visually, together with thresholds are implemented to slow down the velocity of the run-off.
Fig.5-17 - 5-20 Different thresholds: slowing down water (5-17, 5-20) and retaining water in ponds (5-18, 5-19)
Fig.5-21 - 5-23 Pipe’s ends in form of the stone cube are situated along all buildings; they merge the whole area creating its own, specific character
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5.2. Augustenborg, Malmo, Sweden
Fig.5-24 Plan of Augustenborg Ecostaden Augustenborg (Eco-city Augustenborg) is an ecological development in the existing district in Malmo, Sweden. The Eco-city project is made up of several subprojects, one of which is the construction of an open stormwater system. Project was developed in 1998-2002 by the MalmĂś Department of Water and Wastewater. Few years ago Augustenborg experienced damage and inconvenience from basement flooding about 5-6 times a year. It was due to combined sewer and rainwater system that was underdimensioned for modern conditions (where green spaces have been replaced with impervious surfaces) and also due to the pressure from other parts of the city. The goal of the solution is to detain about 70-80% of 30-year rain. In fact in 1997 it was able to take 50-year rain. Water from impervious surfaces is channelled through open and closed canals to pools and filtration swales before finally draining into a traditional stormwater system. Tops of the flat roofs covered with vegetation are able to hold huge amount of rainwater. Holding ponds and temporary flood areas are incorporated to the system which in the first phase stops in a large pool with vegetation. In the second phase water from the
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industrial area is lead through the park as semi-natural stream (filtration swale) to the second pond also containing greenery. Excess water from the housing estate, the school and park ends up in the same place. 17
A.
B.
Infiltration
Retention
1. permeable surfaces
1. sealed filtration swales
18
Augustenborg C. D. Type of device PreConveyance treatment 1. open and closed channels -
2. gutters
2. pools
E. Other 1. pipe’s ends, thresholds, stones, cubes 2. overflow protection
3.green roofs Tab.5-2 Type of devices and its major contribution in the stormwater chain
Fig.5-25 Cross section of stormwater chain (marks are reflection of marks from the table); retention and conveyance are the most significant in the area
A1. Permeable surfaces Augustenborg area is much less sealed than Bo01 (there is a lot of greenery and lawns), but clay soil on the certain level doesn’t allow to water to infiltrate deeply into the groundwater.
The stormwater is running along this permeable layer and riches
basements. So even some devices look like they are able to soak water, they have sealed surface below that doesn’t allow deep infiltration.
17 18
http://www.ekostaden.com http://www.eco-guide.net
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Fig.5-26, 5-27 Surfaces allowing infiltration
Maria Pleśniak
Fig.5-28 Grid of green areas and green roofs
B1. Sealed filtration swales Sealed filtration swales are to transport stormwater to its destination point - retention ponds - allowing also some retention, evaporation and transpiration. They are highly visible in the landscape and incorporated in it very well.
Fig.5-29 – 5-31 Swales are mildly incorporated into the area
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B2. Pools Pools in the Augustenborg have very various forms and in many cases there are multifunctional (Fig.5-36, 5-37, 5-38). Besides aesthetical function they have also very important role to enlarge water capacity of the system.
Fig.5-32 Rainwater delayed on green roofs ends in linear pool along buildings; Fig.5-33 – 5-35 Pools have different shapes and forms: 5-33 and 5-34 have scenic character, 5-35 have geometrical shape Original forms of pools:
Fig.5-36 Rainwater can run through a sand surface for children; Fig.5-37 Basketball court is a large magazine for stormwater; Fig.5-38 Amphitheatre standing on the rainwater way can flood
Fig.5-39 End-ponds have always overflow protection (inflow to the sewer)
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B3. Green roofs Tops of the roofs of buildings for recycling and of the industrial area are usually covered with low maintenance greenery, mainly ‘Sebum’.
Fig.5-40 a,b ‘Sebum’ on low maintenance green roof; Fig.5-41 Presentation of vegetation for low maintenance green roof; Fig.5-42 Low maintenance green roofs can have various, interesting shapes (so it is nice to have view on it from the offices above); Fig.5-43 High maintenance green roof with creepers and small hills
D1. Open and closed channels Channels are very variable, from small to very big; remaining river with small bridges; with very formal and geometrical or informal and natural shapes.
Fig.5-44 - 5-45 Open and closed channels in various sizes and shapes helps to direct water away from buildings
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Fig.5-46 Connection of two different open channels; Fig.5-47 is a picture and Fig.5-48 is a cross-section of open channel combined with swale [m]
E1. Pipe’s ends, thresholds, stones, cubes Pipes ends, thresholds, stones and cubes besides its role to slow down the velocity of the run-off have big esthetical value.
Fig.5-49 – 5-53 Different devices allowing rainwater to be relayed and cleaned from solid pollutants Tear drops create movement in the water, clean off the smaller particles, and allow water to run-off even without slope.
Fig.5-54, 5-55 Big open channel in form of the stream; clogging of stormwater by thresholds gives impression that water is running through the stream when in fact it is not
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E2. Overflow protection Inflow to the sewage is a security that is needed to prevent damages in time of very heavy rains.
Fig.5-56 - 5-58 Overflows (inflows to the sewage) are provided at the end of the ‘stormwater chain’ as additional flood protection
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6. Conclusions Terminology There are some difficulties in describing SUDS and applying terminologies to solutions for example using same terminology for different solutions or many terms for one device (e.g. what is the difference between pond and pool? Can pond be special kind of pool?) There is also gap between professionals and non-professionals in terms of terminology and understanding of the processes when applying technical solutions or advanced technologies. There is hesitancy if the stormwater is polluted and need to be pretreated, what kind of pollutants it contains and what processes/devices might be used to purify the rainwater and how does the regulator know that controlling that specific pollutant alone will prevent pollution from the urban run-off. Collaboration is needed: ‘To provide Sustainable Urban Drainage Systems (SUDS) requires a number of disciplines and agencies (developers, planners, drainage engineers, architects, landscape architects, ecologists and hydrologists) to work in partnership. (…) Planning policy should set the framework in structure and local plans and in masterplanning exercises.’
19
Sustainability The ambition of open stormwater management in Bo01 is to demonstrate how to retain rainwater without allowing water to infiltrate as it usually does. Overflood in this area is not such a big problem as in Augustenborg because of proximity to the sea where the water can be easily discharged. So there is no need of water quantity reduction. Quality of the rainwater shouldn’t be a problem because of car traffic elimination in the area. There is additional energy consumption by pumping tap water, sea water and waste of the potable water (that runs through the ponds). However sustainable solutions try to avoid unnecessary energy consumptions and waste production, from the broader perspective in Bo01 it is not so negative. Previously as an industrial area, Western Harbour is converting today to the high density housing, business and services development. It is located very close to the city centre and is to be attractive. Besides different housing types in the area, attractiveness is provided by well shaped and organised canal and park in the middle of the district, public spaces, semiprivate courtyards and open rainwater system. Water is there important element of the amenity. 19
Sustainable Urban Drainage Systems, http://www.scotland.gov.uk/Publications/2001/07/pan61, accessed: V 2008
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Fig.6-1 Position of the solution in stormwater sustainability triangle (the aim is to increase amenities - the attractiveness of the property) The ambition of open stormwater management in Augustenborg is to prevent damages from flooding. New stormwater solutions are introduced in the area dealing with problem locally: minimising run-off and minimising pressure on the sewage system. Choosing an open stormwater system in which the water is visible has added ecological and aesthetic contribution to the community. The rainwater is no longer seen as a waste but as a resource that adds value to the landscape. Water quantity is highly reduced. There is no rainwater quality control, but it might not be necessary because of character of the area: housing with low traffic volume. The amenity is achieved by good incorporation of different devices and solutions into the landscape. The stormwater chain adds specific character to the place.
Fig.6-2 Position of the solution in stormwater sustainability triangle (the aim is to reduce the amount of run-off, secondary focus is the benefit of the local community)
Determination of sustainability of devices is difficult to define. It depends what devices are chosen, how they are combined, what is the goal to achieve and how it is done. Some solutions that are sustainable alone might be used in non sustainable way. There are also pros and cons of using alternative or supplementary to the sewage system solutions. For usage might be: counterbalance of the sewer system, damages prevention, healthier/sustainable environments, water treated as a resource not waste, savings (not in every case). Against usage might be: difficulty to choose proper devices (size, treatment), big land and surface occupation of devices, worthlessness of SUDS usage if existing sewage system is able to receive stormwater or if construction of the SUDS is too expensive.
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7. Stormwater chain concept project For exemplary conceptual design of stormwater chain a plot with single family house and garden is selected. The aim of the concept is not to design the whole garden, but to solve existing rainwater problems and possible future ones (after sealing of the surface for road and pavement) by stormwater management (run-off reduction and delay) within the plot. To achieve the goal ecological and economical solutions (SUDS described in chapter 3) were selected and combined into a chain that is to be also visually attractive.
Fig.7-1 Position of the solution in context of sustainability (the main focus is water quantity reduction with benefit of dwellers in mind)
7.1. Existing circumstances Site description and location The plot of 13,022 [a] is situated in south-west Poland, near Wroclaw, located on the side road. The traffic volume is inconsiderable (so also pollution from it).
Fig.7-2 South part of the plot with entrance view
Topography The landscape is flat (only ramp leading to garage pitches toward building). Because the garden is not build yet, it is easy to design suitable slopes leading stormwater to chain elements.
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Rainwater’s catchment and drainage House, extended recently about 1/3 of the surface, with a gable roof, has a large impervious surface which collects rainfall and leads it towards gutters.
Because of
lack of sewer system, rainfall is not channelled from the house, but soaks close to the building. As it is large amount of water it causes soil degradation and also foundation damage while soaking. For this reason south part of the roof is channelled to the well, located in the west side of the plot (this part of the roof will be not taken in consideration when solving the rainwater problem). Another impervious surface is the garage entrance – concrete ramp at the rear of the house. In front of ramp after rainfall there is water standing for few hours (it is probably because of the soil that is compacted by vehicles). The stormwater from storage building situated in the north is not collected by drainpipe and falling down from height causes soil scour. The roof of this building is planned to be extended to provide storage room under it. The porch will be built at the entrance to the house. (see Appendix 1)
Soil characteristics In front of the building (south-west) soil is sandy, poor and permeable. East part of the plot contains heavier soil that is fertile. The owner wishes to get there green house and vegetable garden.
Vegetation Whole terrain is covered by unkempt lawn. Keeping lawn in good condition is made hard by soil compression by vehicles that is due to lack of pavement and road. Only south-east side of the plot is planted with fruit trees, which have no big value (they are not cropping well and might be replaced with other trees/vegetation).
Services Telephone wire and water supply system run along the north-west fence, they are in neutral place.
Climate conditions for Poland Poland's climate is moderate (in between the maritime and the continental climates), lying in the zone of atmospheric fronts. This result in fairly wet and mild winters, with average monthly temperature of around 0°C, or heavy and dry winters, with average monthly
temperature
of
-10°C.
A
similar variation
in air temperatures and
precipitation occurs in the summer season, especially during the vegetation period.
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Hot and dry summers (with less than 20 mm of rainfall in June, July and August) may alternate with cold and wet summers with a monthly rainfall up to 150 or even 200 mm. Annual isotherms range between 6.5°C and 8.5°C; average temperatures range from -1°C to -5°C in January and from 17°C to 19°C in June. Average annual rainfall is 583 mm ranging between 500-600 mm in most regions of the country. Two-thirds of annual rainfall occurs in the summer. Snow accounts for two thirds of winter precipitation (December - March). 20
Fig.7-3 Yearly average: precipitation and temperature for Wroclaw.
21
7.2. Proposed solution The project is conceptual rainwater management within the plot presented as a chain. It is not to be detailed garden design, but proposition concentrated on management of stormwater from previous surfaces (roofs, ramp, road and pavement) having of course in mind destination of certain parts of the plot (recreation, vegetable garden) desired by owner. (see Appendix 2, 3 and 4)
20
Country profile – Poland, www.icid.org/cp_poland.html, 21 Country profile – Poland, www.icid.org/cp_poland.html,
International Commission on Irrigation and drainage, accessed: IV 2008 International Commission on Irrigation and drainage, accessed: IV 2008
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7.2.1. Stormwater chain composition The stormwater chain design aims to create more opportunities for storage of rainwater from sealed surfaces and then slowly release it to the ground. A.
B.
Infiltration 1. permeable surface for ramp 2. absorption ditch/trench
C. D. Type of device Retention PreConveyance treatment 1. swale 1. open channels 2. gutters 2. green roof
E. Other 1. thresholds
Tab.7-1 Type of devices and its major contribution in the stormwater chain
Fig.7-4 Cross section of designed stormwater chain (marks are reflections of marks from the table)
A1. Permeable surface for ramp To reduce risk of basement flooding ramp is constructed of previous pavement. At the base of ramp storage container is designed to contain 10 minutes rain of 200 [l/(s·ha)] intensity. Non sealed bottom of the absorption ditch allows infiltration. (see also Fig.7-11)
Fig.7-5 and 7-6 Surface (cobblestones and grass) picture and cross-section
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A2. Absorption ditch/trench In case the amount of water is bigger than infiltration possibility of the permeable ramp surface additional water capacity and infiltration possibility is provided by absorption ditch/trench ( located at the bottom of ramp). (see also Fig.7-10 and 7-11)
B1. Swale Swale stretches along the road running along the plot. It is divided in 5 zones; each zone has different character and plant selection. Rainwater is leaded along the swale to its middle, the deepest part close to the recreational area (zone 2). As unifying elements field stones are placed in each zone of the swale. The bottom is not sealed, so besides storing there is also infiltration function. Two small bridges provide access to the recreational place (zone 2) and green house (zone 4). To create vegetated swale native soil is used (only top layer of the soil has admixture of humus to improve soil conditions for plants).
Fig.7-7 Swale divided into 5 zones Zones division of the swale: Zone 1 – 'dry stream' – low vegetation occupying the swale in a modest way Zone 2 – 'representational area' – the most attractive and the lowest part covered with flowery species Zone 3 – 'shaded greenery' – planted with shadow-loving plants Zone 4 – 'grassy wall' – covered with grasses, attractive also in winter Zone 5 – 'yellow spot' – consist of yellow blooming perennials
B2. Green roof Green roof is to be low maintenance and with light construction. It is able to cope with extreme drought and at the same time to soak up huge amount of rainwater while growing on very thin earth layer (5cm). Covered with ‘Sedum sp.’ attracts bees, butterflies and other insects.
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Fig.7-8 Green roof cross-section
D1. Open channels Two channels (A: gradient 5%, B: gradient 0,5%) made of cobblestones lead water from roofs to the swale. There are designed to contain and lead specific amount of rainwater from roofs to the swale (see 7.2.2. System sizing).
Fig. 7-9 Cross sections of channels B and A [m]
D2. Gutters Besides traditional gutters in form of a pipe, gutters in form of a chain will lead water from green roof and porch to the ground. (see Appendix 3 and 4)
E1. Thresholds Thresholds (in form of containers filled with stones to slow down running water) are implemented to slow down the velocity of the run-off and give some visual attractiveness to the stormwater chain.
Selection of vegetation Vegetation is selected to stand short flood periods and also drought. Outermost south part of the swale (that collects small portion of the rainwater) is covered with more drought resistant plants than innermost and north part. Herbaceous perennials were selected for infiltration swale. They have soft, nonwoody stems that grow each spring from the plant's crown. This quick growth allows higher evaporation than evaporation of woody perennials (trees and shrubs) that have woody stems withstanding cold winter temperatures. As valuable, well cropping fruit tree ‘Prunus domestica’ was left in the middle of the swale.
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Ways of rainwater channelling in cities
Plant name
Type of
Height
plant
[m]
Flowers
Maria Pleśniak
Moisture
Sun
tolerance
exposition
Swale - zone 1 Primula denticulata ‘Alba’ and ‘Rubin’
perennial 0,07-0,1
white, purple
Sedum acre
perennial 0,04
yellow
Saxifraga arendsii
perennial 0,04
purple
Pennisetum alopecuroides
grass
wet dry
medium,
0,3-0,6
wet
Swale - zone 2 Echinacea purpurea
perennial 0,7
violet
wet
Hemerocalis hybrida
perennial 0,5-1,0
red, yellow wet
Sedum spectabile
perennial 0,4
pink
dry
yellow
wet
Swale – zone 3 Rheum palmatum
perennial 1,8
Alchemilla molis
perennial 0,4
yellowgreen
dry
Swale - zone 4 Miscanthus sinensis
grass
1,5
wet
Deschsampsia cespitosa
grass
1,5
wet
Rudbeckia fulgida
perennial 0,6
'Cosmopolitan'
yellow
wet
wet
Swale - zone 5 Lysimachia clethroides
perennial 0,7
white
Achillea tomentosa
perennial 0,8
yellow
Green roof Sedum rupestre
perennial 0,05
yellow
dry
Sedum acre
perennial 0,04
yellow
dry
Sedum album
perennial 0,06
white
dry
Tab.7-2 Plants selection for the area
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7.2.2. System sizing 22 Total property surface [m2]:
1302,2
Green areas:
886,4
Pavement:
235,2
(for calculations: 179,4)
Roofs:
179,9
(for calculations: 112,3)
Total surface for calculations:
291,7
Ramp:
50,8
(slope not to the system, so calculations for this surface are made separately) Computational rainfall intensity event 23 Rainfall intensity event calculations for Poland are: 101 [l/(s · ha)]
(with 1 year frequency)
127 [l/(s · ha)]
(with 2 years frequency)
173 [l/(s · ha)]
(with 5 years frequency)
Because of climate changes and abnormalities these changes bring, computational rainfall intensity event is taken bigger that seems to be needed, it is: 200 [l/(s · ha)]. 1[l] = 0,001 [m3] 10 [min] = 600 [s] 1[ha] = 10 000 [m2] Calculations: For computational rainfall in 10 minutes (R10), for total surface for calculations 291,7 [m2] (project requirements) R10 = 291,7 [m2] · 0,00002 [m/s] · 600 s = 3,5 [m3] Test points To show if channel is able to contain rain fallen on the surface it is necessary to compare water-flow (Q) to amount of rainfall on the surface (K) in characteristic points. Assumption: Q>=K
22 23
Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999 Edel R., Odwodnienie dróg, Wyd. Kominikacji i Łączności, Warszawa 2000, 2006
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Calculations for the channel A: Average water-flow speed [v] and water flow [Q] in the stream-bed (A) for trapezoid cross-section: slope1:
Is1 = 4% = 0,04 [-]
slope2:
Is2 = 5% = 0,05 [-]
depth of stream-bed:
h = 3 [cm]
stream-bed crown width:
b = 5 [cm]
buttress:
lF = 4 [cm]
width of stream-bed: B = b + 2(lF2 – h2)1/2 = 10,29 [cm] wet perimeter: lzw = b + 2 lF = 13 [cm] buttress slope (indignation): n = (lF2 – h2)1/2 /h = 0,33 [-] water-flow cross-section: A = b·h+n·h2=17,92[cm2] = 0,001792[m3] hydraulic radius: rhy = A/lzw = 1,21 [cm] = 0,0138 [m] roughness number for cobble stone: kst = 60 [m1/3/s] water-flow speed1: v1 = kst · rhy2/3 · Is11/2 = 0,7104 [m/s] water-flow1: Q = v1 · A = 0,001276 [m3/s] = 1,276 [l/s] KA = 65,1 [m2] · 0,00002 [m/s] = 0,001302 [m3/s] = 1,302 [l/s] Q>=KA 1,276 [l/s]>=1, 302 [l/s] FALSE Conclusions: Channel is not big enough to contain rain felled on the surface in characteristic points.
water-flow speed2: v2 = kst · rhy2/3 · Is21/2 = 0,7942 [m/s] water-flow2: Q = v2 · A = 0,001427 [m3/s] = 1,427 [l/s] KA = 65,1 [m2] · 0,00002 [m/s] = 0,001302 [m3/s] = 1,302 [l/s] Q>=KA 1,427 [l/s]>=1,302 [l/s] TRUE Conclusions: Channel is big enough to contain rain felled on the surface in characteristic points.
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Calculations for the channel B: Average water-flow speed [v] and water flow [Q] in the stream-bed (B) for trapezoid cross-section: slope:
Is = 0,5% = 0,005 [-]
depth of stream-bed:
h = 2 [cm]
stream-bed crown width:
b = 1 [cm]
buttress:
lF = 4 [cm]
width of stream-bed: B = b +
2(lF2 –
h2)1/2 = 8,74 [cm]
wet perimeter: lzw = b + 2 lF = 9 [cm] buttress slope (indignation): n = (lF2 – h2)1/2 /h = 0,82 [-] water-flow cross-section: A = b·h+n·h2 = 5,28[cm2] = 0,000528[m3] hydraulic radius: rhy = A/lzw = 0,58 [cm] = 0,0058 [m] roughness number for cobble stone: kst = 60 [m1/3/s] water-flow speed: v = kst · rhy2/3 · Is1/2 = 0,1417 [m/s] water-flow: Q = v · A = 0,00007481 [m3/s] = 0,07481 [l/s] KB = 2,5 [m2] · 0,00002 [m/s] = 0,00005 [m3/s] = 0,05 [l/s] Q>=KB 0,07481 [l/s]>= 0,05 [l/s] TRUE
Conclusions: Channel is big enough to contain rain felled on the surface in characteristic points. Water capacity of designed system: Swale: layers
surface [m2]
depth [m]
a
30,05
0,0
b
18,60
–0,1
c
10,27
–0,2
d
6,05
–0,3
e
4,24
–0,4
f
1,84
–0,5
g
0,44
–0,6
Tab.7-3 Swale levels – surface and depth depth of each swale layer:
h=0,1 [m]
swale capacity: Rc = g·h+f·h+e·h+d·h+c·h+b·h = h·(g+f+e+d+c+b) = 7,91 [m3] (Channel capacity is 'undercalculated', so first layer is not taken into consideration.)
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Assumption: Swale capacity (Rc) has to be bigger than computational rainfall (R10) for impervious surfaces sloped towards the system and computational rainfall felled into the swale (R10s). Rc = 7,91 [m3] R10 = 291,7 [m2] · 0,00002 [m/s] · 600 s = 3,5 [m3] R10s = 30,05 [m2] · 0,00002 [m/s] · 600 s = 0,36 [m3] Rc>=(R10 + R10s) 7,91 [m3] >= 3,86 [m3] TRUE
Conclusions: System capacity is big enough to contain 10 minutes rain of 200 [l/(s·ha)] intensity. Calculations for the ramp (aside of designed stormwater chain): Computational rainfall in 10 minutes (R10) for ramp surface 50,8 [m3]: R10 = 50,8 [m2] · 0,00002 [m/s] · 600 s = 0,6 [m3] Ramp capacity:
Fig.7-10, 7-11 Ramp and absorption ditch/trench: plan and cross-section width of the ramp: 8,45 [m] V1 = 8,45 · 0,2 · 0,15 = 0,2535 [m3] V2 = 8,45 · 0,03 · 1,0 = 0,38 [m3] V = V1 + V2 = 0,25 + 0,38 = 0,63 [m3] V >=R10 0,63 [m3]>= 0,6 [m3] TRUE
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Conclusions: Ramp capacity is big enough to contain 10 minutes rain of 200 [l/(s·ha)] intensity.
7.3. Summary With city expansion suburban areas develop to areas of detached housing. The rainwater management problems in those areas are seen not until added up create serious flooding danger (small stormwater trouble within the plot increase when accumulated by number of plots). The solution is seen in rainwater management in micro scale on the site (so where in fact the problem begins).
Fig. 7-12 Example of rainwater channelling via underground pipe systems to sewage treatment plants
Fig. 7-13 Example of rainwater channelling on the site with overflow protection to the sewage
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The conceptual design described above is to be an educational and example how to manage rainwater in the spot in small scale by applying simple, transparent, environmental and people friendly solutions that are SUDS. Proposed rainwater chain illustration
can
be
used
by
municipalities
to
promote
sustainable
rainwater
management on the site. Applied in multiple number in effective way can prevent negative results of surface sealing.
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8. Bibliography 1. 2. 3.
4. 5. 6. 7. 8. 9.
10. 11. 12. 13. 14. 15. 16. 17. 18. 19.
20. 21.
22. 23. 24. 25. 26.
A Green Vitruvius – Principles and Practice of Sustainable Architectural Design, James & James, London 1999 Amenity, http://en.wikipedia.org/wiki/Amenity, accessed: V 2008, http://en.wiktionary.org/wiki/amenity, accessed: V 2008 Augustenborg, http://www.ekostaden.com/information/ekostaden_tmpl_01.aspx?pageID=93& parentID=176&sectionID=4&level=4&introID=146, accessed: V 2008 Augustenborgs Botanical Roof Garden, http://www.greenroof.se, accessed: IV 2008 Andersson L.S., The Anchor Park, A+U Publishing, 2002 Bannerman R., Considine E. Rain Gardens - A how-to manual for homeowners, Wisconsin Department of Natural Resources, DNR Publication, 2003 Bo01 Quality Programme, Bo01 City of Tomorrow, The City of Malmö and the developers, 1999 Country profile – Poland, International Commission on Irrigation and drainage, www.icid.org/cp_poland.html, accessed: IV 2008 D’Arcy BJ., Urban best management practice. In: Pratt CJ, editor. Proceedings of the Fifteenth Meeting of the Standing Conference on Stormwater Source Control, School of The Built Environment, Coventry University, 1998 Dirckinck-Holmfeld K., Moldrup S., Amundsen M, Sorensen L. L., Danish ecological building; The Danish Architectural Press, 1994 Dreiseitl H., Grau D., Ludvig K.H.C., Waterscapes- Planning, Building und Designing with Water, Birkhäuser, Basel 2001 Due N., Gottschalk I. M., Stormwater in the city – Use of stormwater on Thomas B. Thriges Gade in Odense, Copenhagen 2008 Dunnett N., Clayden A., Rain Gardens - Managing water sustainably in the garden and designed landscape, Timber Press, Portland 2007 Ekostaden Augustenborg, http://www.ecoguide.net/malmo/Ekostaden_Augustenborg_project.php, accessed: VI 2008 Edel R., Odwodnienie dróg, Wyd. Kominikacji i Łączności, Warszawa 2000, 2006 Edwards B., Hyett P., Rough Guide To Sustainability, RIBA Publications, London 2002 Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Projprzem-EKO, Bydgoszcz 1999 Green map Augustenborg, http://www.greenguide.nu/august/engindex.html, accessed: V 2008 Hancock C., Towards a sustainable city, http://www.malmo.se/download/18.4a2cec6a10d0ba37c0b800012617/article_t owards_sustainable_city.pdf, accessed: 2008 Katalog roślin II - drzewa, krzewy, byliny polecane przez Związek Szkółkarzy Polskich, Agencja Promocji Zieleni , Warszawa 2003 Lundberg L., Green Roof Demonstration and Research Center – Developing Further, http://www.greenroofs.com/archives/gf_apr04.htm, accessed: VI 2008 Managing urban stormwater: harvesting and reuse, Department of Environment and Conservation NSW, Sydney 2006 Malbert B., Ecology-based planning and construction in Sweden, The Swedish Council for Building Research, Stokholm, 1998 Marcinkowski M., Katalog Bylin polecanych przez Związek Szkółkarzy Polskich, Agencja Promocji Zieleni, Warszawa 2005 Mary C. H., Low-Impact Development, The Journal for Surface Water Quality Professionals ‘Stormwater Features’, Minesota 2006 Merret S., The price of water. Studies in water resource economics and management, IWA Publishing, London 2005
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Ways of rainwater channelling in cities 27. 28.
29.
30.
31. 32. 33. 34. 35. 36. 37.
38.
39.
40.
Maria Pleśniak
Miffin W., Polluted urban runoff, 1997 Minesota Stormwater Manual, Pollution Control Agency, Minesota 2006 (available at: http://www.pca.state.mn.us/water/stormwater/stormwatermanual.html) Morten E., lntegrated Solutions in Urban Ecology - Dream or Reality in The European City - Sustaining Urban Quality, Ministry of Environment and Energy, Copenhagen 1996 Mortensen P. K., Rasmussen C. O., An overview of water recycling and wetland uses for biofiltration of irrigation and runoff water, The Royal Veterinary and Agricultural Uniwersity, Copenhagen 2002 Munkstrup N., Lindberg J., Urban Ecology Guide – Greater Copenhagen, Dansk Byplanlaboratorium/Danish Town Planning Institute, 1996 Muthanna T.M., Sveinn T.T., Winter hydrology in a cold climate rain garden, ASABE, 2006 Pearce D., Barbier E., Markandya A., Sustainable Development, Edward Elgar, 1990 Robets H., Bo01 City of Tomorrow, http://home.att.net/~amcnet/bo01.html, accessed: V 2008 Seymour R. M., Capturing rainwater to replace irrigation water for landscapes: rain harvesting and rain gardens, Minesota Pollution Control Agency, 2003 Shaw D., Schmidt R., Plants for Stormwater Design, Minesota Pollution Control Agency, 2003 Stormwater teaching guide, http://www.environment.nsw.gov.au/stormwater/HSIEteachguide/index.htm, accessed: V 2008 Sustainable Urban Drainage Systems, http://www.scotland.gov.uk/Publications/2001/07/pan61, accessed: V 2008 http://en.wikipedia.org/wiki/Sustainable_urban_drainage_systems, accessed: V 2008 The green city, http://www.malmo.se/servicemeny/malmostadinenglish/sustainablecitydevelop ment/augustenborgecocity/thegreencity.4.1dacb2b108f69e3b8880002102.html accessed: IV 2008 Vastra Hamnen The Bo01-area, http://www.ekostaden.com/pdf/vhfolder_malmostad_0308_eng.pdf, accessed: V 2008
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9. Index of figures, tables and appendices Figures Fig.2-1 Fig.3-1
Fig.3-2
Fig.3-3
Fig.3-4
Fig.3-5
Fig.4-1
Fig.4-2
Fig.4-3
Fig.4-4
Fig.4-5
Fig.4-6
Fig.4-7 Fig.4-8
Fig.4-9 Fig.4-10 Fig.4-11
Fig.4-12
Fig.4-13
Fig.4-14
Flow chart illustrating formation of this paper Maria Pleśniak Proportions in stormwater distribution depending on sealing of the surface (level of the development) Adapted from: Dunnett N., Clayden A., Rain Gardens - Managing water sustainably in the garden and designed landscape, Timber Press, Portland 2007 Infiltration, evapotranspiration and run-off have different proportions in natural areas and developed areas Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Treatment of harmful substances in soil (mechanical, physiochemical and microbiological processes) Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Global Development up to 1987, Global Development after 1987 Adapted from: Edwards B., Hyett P., Rough Guide To Sustainability, RIBA Publications, London 2002 SUDS deal in an integrated way with issues of water quantity, water quality and amenity Adapted from: D’Arcy BJ., Urban best management practice. In: Pratt CJ, editor. Proceedings of the Fifteenth Meeting of the Standing Conference on Stormwater Source Control, School of The Built Environment, Coventry University, 1998 Permeable parking lot allows water to infiltrate on the site Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Examples of surfaces (vegetated, not vegetated, strengthened and not strengthened) that allow infiltration on the site http://blender-archi.tuxfamily.org/images/GRASS.JPG Examples of surfaces (vegetated, not vegetated, strengthened and not strengthened) that allow infiltration on the site http://www.appropedia.org/images/thumb/5/56/Permeable_pavement.JPG/180pxPermeable_pavement.JPG Examples of surfaces (vegetated, not vegetated, strengthened and not strengthened) that allow infiltration on the site http://farm1.static.flickr.com/17/92755297_b0fbfd8de0.jpg?v=0 Examples of surfaces (vegetated, not vegetated, strengthened and not strengthened) that allow infiltration on the site http://www.re-nest.com/re-nest/look/beyond-concrete-permeable-paving-026148 Examples of surfaces (vegetated, not vegetated, strengthened and not strengthened) that allow infiltration on the site http://www.chesshirstone.com/images/materials_images/materials_gravel_apache_pea.jpg Cross-section of a rain garden/bioretention area Adapted from: Minesota Stormwater Manual, Pollution Control Agency, Minesota 2006 Rain garden with perennials (evaporation of perennials is big because of its fast growing as contrasted with threes and shrubs) http://www.rfcity.org/Eng/Stormwater/YourProperty/YourProperty.htm Grass swale in Augustenborg, Malmo has double task: transportation and on-lot infiltration Maria Pleśniak This linear rain garden at campus of University of California in Merced, USA is beautifully incorporated in the landscape http://flickr.com/photos/jollyroberts/2578682788/ Bioretention area at University of Illinois at Urbana-Champaign, USA adds specific character to the area and looks attractive with water and also without (spring set) http://flickr.com/photos/cicick1/468001422/ Bioretention area at University of Illinois at Urbana-Champaign, USA adds specific character to the area and looks attractive with water and also without (autumn set) http://flickr.com/photos/brokenthoughts/2245098657/ Cross-section of an infiltration pool Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Soakaway cross-section Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999
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Ways of rainwater channelling in cities
Fig.4-15
Fig.4-16
Fig.4-17
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Fig.4-19 Fig.4-20
Fig.4-21 Fig.4-22
Fig.4-23
Fig.4-24 Fig.4-25 Fig.4-26
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Fig.4-36 Fig.4-37 Fig.5-1
Maria Pleśniak
Soakaway inflow hidden in stones Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Cross-section of absorption ditches with (a) point inflow and (b) surface inflow Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Construction of an absorption ditch Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Cross-section of a grass filtration swale Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Cross-section of a vegetated swale with sealed bottom Adapted from: Minesota Stormwater Manual, Pollution Control Agency, Minesota 2006 Cross-section of a retention and filtration pool Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Retention pool in Augustenborg, Malmo attracts people (sitting place close to the water) Maria Pleśniak Roof with clogging of water Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Green roof Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Green roofs are not a new invention; Pictures show 18th century farm from Sweden (Open Air Museum in Copenhagen) Maria Pleśniak Cross-section of a sedimentation well Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Cross-section of a soakaway with sedimentation tank Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Removal of sediments from the bag Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Vegetation passage cross-section and an example of vegetation passage Adapted from: Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. Projprzem-EKO, Bydgoszcz 1999 Vegetation passage cross-section and an example of vegetation passage Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Rainwater is channelled away from building Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Threshold in form of a stream acting as a bump (slowing traffic speed) Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Semi open channel to the stormwater planter Dunnett N., Clayden A., Rain Gardens - Managing water sustainably in the garden and designed landscape, Timber Press, Portland 2007 Open channel changing into closed (under pavement) to allow easy pedestrian traffic Dunnett N., Clayden A., Rain Gardens - Managing water sustainably in the garden and designed landscape, Timber Press, Portland 2007 Gutters in form of a chain leading water from the roof to the ground Geiger W., Dreiseitl H., Nowe sposoby odprowadzania wód deszczowych, Wyd. ProjprzemEKO, Bydgoszcz 1999 Gutters in form of a chain leading water from the roof to the ground Dunnett N., Clayden A., Rain Gardens - Managing water sustainably in the garden and designed landscape, Timber Press, Portland 2007 Stormwater chain example consisting of various devices that reduce run-off by delaying it, storing and infiltrating Adapted from: Dunnett N., Clayden A., Rain Gardens - Managing water sustainably in the garden and designed landscape, Timber Press, Portland 2007
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Ways of rainwater channelling in cities
Fig.5-2 Fig.5-3
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Fig.5-17 Fig.5-18 Fig.5-19 Fig.5-20 Fig.5-21 Fig.5-22 Fig.5-23 Fig.5-24 Fig.5-25
Fig.5-26 Fig.5-27 Fig.5-28 Fig.5-29 Fig.5-30 Fig.5-31 Fig.5-32 Fig.5-33 Fig.5-34 Fig.5-35 Fig.5-36 Fig.5-37 Fig.5-38 Fig.5-39 Fig.5-40 a,b Fig.5-41
Maria Pleśniak
Bo01 development plan Maria Pleśniak The amenity aspect is maintained by numerous works of art (sculptures, fountains) spread around the area; picture show autumn set of one of art works Marina Bergen Jensen The amenity aspect is maintained by numerous works of art (sculptures, fountains) spread around the area; pictures show summer set of one of art works Maria Pleśniak Cross section of stormwater chain (marks are reflections of marks from the table) Maria Pleśniak Grid of green areas and green roofs Maria Pleśniak Pools with vegetation (a) are located on public squares and along the main walking paths; supply with water is provided by rainwater and tap water running through it Maria Pleśniak Pools with vegetation (a) are raised to avoid melting of salted water from the canal (b) with sweet water form pools; as we can see on the pictures pools have high aesthetical values during vegetation season Maria Pleśniak The sea water is pumped into the canal to keep it wet and attractive Maria Pleśniak ‘Sedum’ gives reddish colour to the ‘roof landscape’ Maria Pleśniak Cross sections of channels [m] Maria Pleśniak However, some channels seem to be only a dummy going up the slope (as we can see on the picture) Maria Pleśniak Different thresholds: slowing down water (5-17, 5-20) and retaining water in ponds (5-18, 5-19) Maria Pleśniak Pipe’s ends in form of the stone cube are situated along all buildings; they merge the whole area creating its own, specific character Maria Pleśniak Plan of Augustenborg Maria Pleśniak Cross section of stormwater chain (marks are reflection of marks from the table); retention and conveyance are the most significant in the area Maria Pleśniak Surfaces allowing infiltration Maria Pleśniak Grid of green areas and green roofs Maria Pleśniak Swales are mildly incorporated into the area Maria Pleśniak Rainwater delayed on green roofs ends in linear pool along buildings Maria Pleśniak Pools have different shapes and forms: 5-33 and 5-34 have scenic character, 5-35 have geometrical shape Maria Pleśniak Rainwater can run through a sand surface for children Maria Pleśniak Basketball court is a large magazine for stormwater Maria Pleśniak Amphitheatre standing on the rainwater way can flood Maria Pleśniak End-ponds have always overflow protection (inflow to the sewer) Maria Pleśniak ‘Sebum’ on low maintenance green roof Maria Pleśniak Presentation of vegetation for low maintenance green roof Maria Pleśniak
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Ways of rainwater channelling in cities
Fig.5-42
Fig.5-43 Fig.5-44 Fig.5-45 Fig.5-46 Fig.5-47 Fig.5-48 Fig.5-49 Fig.5-50 Fig.5-51 Fig.5-52 Fig.5-53 Fig.5-54 Fig.5-55 Fig.5-56 Fig.5-57 Fig.5-58 Fig.6-1
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Fig.7-13
Maria Pleśniak
Low maintenance green roofs can have various, interesting shapes (so it is nice to have view on it from the offices above) Maria Pleśniak High maintenance green roof with creepers and small hills Maria Pleśniak Open and closed channels in various sizes and shapes helps to direct water away from buildings Maria Pleśniak Connection of two different open channels Maria Pleśniak Picture of open channel combined with swale Maria Pleśniak Cross-section of open channel combined with swale [m] Maria Pleśniak Different devices allowing rainwater to be relayed and cleaned from solid pollutants Maria Pleśniak
Big open channel in form of the stream; clogging of stormwater by thresholds gives impression that water is running through the stream when in fact it is not Maria Pleśniak Overflows (inflows to the sewage) are provided at the end of the ‘stormwater chain’ as additional flood protection Maria Pleśniak Position of the solution in stormwater sustainability triangle (the aim is to increase amenities - the attractiveness of the property) Maria Pleśniak Position of the solution in stormwater sustainability triangle (the aim is to reduce the amount of run-off, secondary focus is the benefit of the local community) Maria Pleśniak Position of the solution in context of sustainability (the main focus is water quantity reduction with benefit of dwellers in mind) Maria Pleśniak South part of the plot with entrance view Maria Pleśniak Yearly average: precipitation and temperature for Wroclaw. Country profile – Poland, International Commission on Irrigation and drainage, www.icid.org/cp_poland.html, accessed: IV 2008 Cross section of designed stormwater chain (marks are reflections of marks from the table) Maria Pleśniak Surface (cobblestones and grass) picture and cross-section http://texturez.com/textures/stone/692 Surface (cobblestones and grass) picture and cross-section Maria Pleśniak Swale divided into 5 zones Maria Pleśniak Green roof cross-section Maria Pleśniak Cross sections of channels B and A [m] Maria Pleśniak Ramp and absorption ditch/trench: plan and cross-section Maria Pleśniak Ramp and absorption ditch/trench: plan and cross-section Maria Pleśniak Example of rainwater channelling via underground pipe systems to sewage treatment plants Maria Pleśniak Example of rainwater channelling on the site with overflow protection to the sewage Maria Pleśniak
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Ways of rainwater channelling in cities
Maria Pleśniak
Tables Tab.5-1
Tab.5-2 Tab.7-1 Tab.7-2 Tab.7-3
Type of devices and its major contribution in the stormwater chain; conveyance and retention are the most significant in the area Maria Pleśniak Type of devices and its major contribution in the stormwater chain Maria Pleśniak Type of devices and its major contribution in the stormwater chain Maria Pleśniak Plants selection for the area Maria Pleśniak Swale levels – surface and depth Maria Pleśniak
Appendices 1.
Existing circumstances
2.
Conceptual design – plan
3.
Cross-sections
4.
Stormwater chain elements
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