Rainwater management for urban drainage, groundwater recharge and storage

Transcription

1 Rainwater management for urban drainage, groundwater recharge and storage M. Jekel Technical University of Berlin Dept. of Water Quality Control H. Sieker Ingenieurgesellschaft Prof. Sieker (IPS), Berlin, Germany

2 Conventional Urban Drainage

3 Disturbance of Water Cycle Source: US-EPA Quelle: US-EPA, 2004 (angepasst)

4 Increase of runoff Natural water cycle Urban water cycle High Evapo- Transpiration Low Evapo- Transpiration Low Surface runoff High Surface-runoff High Groundwaterrenewal Low Groundwaterrenewal Pictures: Geiger/Dreiseitl

5 Urban Flooding Athens, Greece, 2007

6 Impact on water quality

7 Impact on River Morphology Pictures: Podraza

8 Cost of Stormwater Drainage Germany: most municipalities have a stormwater fee Cost for stormwater drainage is not included in fees for drinking water and waste water Base for stormwater fee: area connected to sewer Typical fee (Berlin): ~2 /m²/year Examples for fees a) Private house (150 m² connected) 300 /year b) Supermarket ( ² connected) /year c) Supermarket (disconnected, infiltration) 0 /year

9 Paradigm Shift Development of new strategies in last years New technical rules New legal regulations : a) Water Framework Directive in Europe b) Regulation for Infiltration in regional water laws c) New stormwater act has been released 2010 New Term: Stormwater Management

10 Urban drainage options Lot of different solutions are possible SW Harvesting Infiltration Transpiration Retention Treatment Drainage

11 Rainwater Harvesting Rainwater harvesting for non-potable use is quite common in Germany a) In private households for garden watering, toilet flushing, washing b) Also in public buildings c) For commercial purposes SW Harvesting

12 Stormwater Infiltration Permeable surfaces Infiltration

13 Stormwater Infiltration Permeable surfaces Swales Infiltration

14 Stormwater Infiltration Permeable surfaces Swales Underground infiltration Infiltration

15 Retention Ponds Retention tanks Retention

16 Green roofs Evapotranspiration Transpiration

17 Evapotranspiration Green roofs Ponds, constructed wetlands Transpiration

18 Stormwater Treatment Large variety of technical solutions Treatment

19 Innolet Idea: Clean road runoff at the source Overhead suspension Emergency overflow 12 Ø35 mm Overflow dirt t rap 12 Ø35 mm 4 sections grille network (with 5 mm mesh size) 4 sections grille network (with 1 mm mesh size) St reet Inlet Perforated bottom Basket for retainment of solid material like sand or leaves Filterbasket with filter mat erial Sewer Sludge collect ion area INNOLET -Filtercartridge

20 Drainage Pipes, channels, gutters Open drainage systems Ableitung Foto M. Kaiser Foto K. König

21 Combined Systems Swale-Trench-System Infiltration Transpiration Retention Treatment Drainage Soil-layer d-30cm Trough Overflow Trough Manhole Overflow trench Trench Drain pipe Throttle

22 Modern approach Outlet of 100 hectare commercial development!

23 Groundwater recharge - 1 Protected Groundwater is the best source for drinking water Seasonal recharge in rainy periods, like in Chile and Germany Storage capacity is high to balance periods of high demand Purification effects of groundwater are well documented, including removal of microbial and chemical pollutants Rule of thumb: 50 days retention time in a porous aquifer provide a hygienically safe water (for artifical gw recharge) Groundwater recharge belongs to the natural underground treatment systems, like bankfiltration with a long-time experience (> 100 years)

24 Groundwater recharge - 2 Rain water and run-off are suitable unconventional water resources, but need special design and treatment. Options for emergency water supply by decentralised hand pumps: Berlin: Public hand pumps with supply radius of 200 m are provided Optional solution also for permanent decentralized water supply at house-hold or village level by integration into the infrastructure of houses or settlements Recharge at 200 mm provides 200 cbm per year on only 1000 sqm, enough for 4 5 people Protection of groundwater against other pollution required (sewage infiltration, agricultural chemicals)

25 Conclusion Lots of technical solutions for urban water are available Usage Infiltration Transpiration Retention Treatment Drainage Optimal solutions usually are combinations Sustainable water management means looking for adapted solutions Challenge for the engineer

26 Thank you for your attention!