climate adaptation, innovative suds and protection of harrestrup Å by sille lyster larsen, grontmij...
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- Slide 1
- CLIMATE ADAPTATION, INNOVATIVE SUDS AND PROTECTION OF HARRESTRUP By Sille Lyster Larsen, Grontmij & Vinni Rnde, MSc Hydrology, Wageningen UR Retrofitting Baunebakken, Hvidovre 1
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- Hvidovre Introduction 2 2 l/s/ha
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- What was done Increased permeable surface -Hydraulic model -Calibration with flow and rainfall measurements -Terrain analysis -Is subsurface flow possible? -Designing the SuDS -Iterative design process: design and functionality -Public involvement in Baunebakken -Creating ownership and getting feedback -Cost analysis -Testing traditional pipes versus SuDS 3
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- Retrofitting the system 4
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- Rain gardens and filter trench 5
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- Design of rain gardens Grundkr 6: Filling material: soil Drainage: pipe Size: 1,5x1,5m Vegetation: plants Grundkr 8: Filling material: Top: soil Btm: pebble gravel Drain: gravel spillway Size: 2x2m Vegetation: plants Grundkr 10: Filling material: Top: soil/stones Btm: pepple gravel Drain: stone well Size: 1,5x2m Vegetation: grass Grundkr 4: Filling material: soil Drain: pipe and gravel spillway Size: 1,5x1,5m Vegetation: plants 6
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- Plan view of rain gardens Outlet to sewer network roof 7 Rain garden
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- Plan view of experimental setup roof Outlet to sewer network Inlet Location of flow measurements 8 Rain garden roof
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- Method: Irrigation experiment Rainfall events Return period (year) Duration (min) Climate factor Intensity (L/s/ha) 5101193 10201,43226 Water from fire hydrant was sprayed on the roofs with flow rates equal to: 9
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- Method: water level measurements soil pebble gravel drain pipe short piezometer for surface water measurements gravel spillway long piezometer for water level measure- ments in the bottom 75mm pipe trench water from roof permeable membrane diver 80cm 10
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- Results: Grundkr 4 -Drain pipe not in use during the 5-year return period event -Overflow during 10-year return period event 11
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- Results: Grundkr 6 -Overflow during 5- and 10-year return period events -Lekage to penetrating piezometer error in bottom water level 12
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- Results: Grundkr 8 -Overflow during 5- and 10-year return period events -Design error: level of spillway higher than level of lowest edge of rain garden 13
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- Results: Grundkr 10 -No overflow -OBS: Reduced flow to rain garden due to overflow of rain gutter 14
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- Summary of results -Volume capacity of rain gardens was far from reached during a 5- and 10-year return period of 10 and 20 min duration, respectively. -Infiltration is the limiting factor in rain gardens with plants Ponding and overflow occurred -Direct comparison of rain gardens is difficult o uncertainty in flow o design errors o variation in ratio roof area / rain garden area 15
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- Final design of rain gardens The grass rain garden: -Rain garden similar to that at Grundkr 10 -Reduction of depth from 80 to 50 cm (decrease of material expenses) The plant rain garden: -Rain garden similar to that at Grundkr 4 -A drainpipe has been excluded due to risk of clogging in the long run With these designs the rain gardens are able to convey a 5-year return period rain of 10 min duration 16
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- Conclusion -Climate change adaptable system -The required volume was found through decentralized SuDs elements -Runoff delayed to 2 L/s/ha protection of Harrestrup -Lower cost than a traditional pipe design 17
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- Conclusion -The overall design is being implemented and expected to be completed by August/September 2014 18
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- Thank you 19 -Vinni Rnde, vikar@student.dtu.dk -Sille Larsen, sll@grontmij.dk
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