CLIMATE ADAPTATION, INNOVATIVE SUDS AND PROTECTION OF HARRESTRUP Å By Sille Lyster Larsen, Grontmij...
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CLIMATE ADAPTATION, INNOVATIVE SUDS AND PROTECTION OF HARRESTRUP Å By Sille Lyster Larsen, Grontmij & Vinni Rønde, MSc Hydrology, Wageningen UR Retrofitting
CLIMATE ADAPTATION, INNOVATIVE SUDS AND PROTECTION OF
HARRESTRUP By Sille Lyster Larsen, Grontmij & Vinni Rnde, MSc
Hydrology, Wageningen UR Retrofitting Baunebakken, Hvidovre 1
Slide 2
Hvidovre Introduction 2 2 l/s/ha
Slide 3
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
Plan view of rain gardens Outlet to sewer network roof 7 Rain
garden
Slide 8
Plan view of experimental setup roof Outlet to sewer network
Inlet Location of flow measurements 8 Rain garden roof
Slide 9
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
Slide 10
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
Slide 11
Results: Grundkr 4 -Drain pipe not in use during the 5-year
return period event -Overflow during 10-year return period event
11
Slide 12
Results: Grundkr 6 -Overflow during 5- and 10-year return
period events -Lekage to penetrating piezometer error in bottom
water level 12
Slide 13
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
Slide 14
Results: Grundkr 10 -No overflow -OBS: Reduced flow to rain
garden due to overflow of rain gutter 14
Slide 15
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
Slide 16
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
Slide 17
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
Slide 18
Conclusion -The overall design is being implemented and
expected to be completed by August/September 2014 18
