SUDS in the River Lea Stratford Flashcards
What are sustainable urban drainage systems (SUDS)
Sustainable urban drainage systems aim to minimise runoff from buildings and paved areas by measures such as retaining water from re-use, increasing infiltration into the ground by using permeable surfaces and ‘soak ways’, or incorporating retention basins and wetlands alongside new developments.
Examples of SUDS
-Permeable surfaces such as porous linings around trees and grassed areas
-Infiltration trenches
-Rainwater harvesting- ponds and swales
-Underground storage
-Green roofs and walls
-Wetlands
General benefits of SUDS
-Enhanced biodiversity
-Improved water quality
-Improved air quality
-Flood risk managment/drought managment
-Recreation oppourtunities
Background of the River Lea
-The Olympic Park development in Stratford, East London, covers an area of approximately 250ha and housed the Olympic stadium, aquatic centre and copper box.
-The site was formerly industrial/commercial developments, with the Lea Valley Park as a known depository for building rubble from properties demolished during the Second World War.
-The site overlays deposits of river terrace gravel and chalk aquifer and t was known to be contaminated throughout due to the industrial developments on it.
Characteristics of the River Lea
- A number of watercourses traverse the park, incldyding the River Lea, River Lee Navigation, Waterworks River, City Mill River and the Old River Lea.
-The park was designed to be protected against river flooding within a 100 year return rainfall event.
-The site topography was dramatically changed during the course of the development, with some areas of the park raised by 9m.
-In addition, the creation of the wetland bowl within the River Lea valley required significant widening of the river channel, reducing land levels around it.
-Plateaux have been formed for the sporting venues and associated facilities above the river flood level with access routes to the lower level f the towpaths adjacent to the watercourses.
SUDS used in the river lea (asphalt)
-Porous asphalt strips are extensively employed throughout the pedestrian concourses of the park. These act as collection points for any runoff generated and contest water into trenches below the strips which contain perforated pipes.
SUDS strategies in River Lea (perforated pipes)
The perforated pipes are made from recycled thermoplastic materials and train to catch pits and then into the rivers/watercourses.
River Lea SUDS- swales and balancing ponds
Within the wetlands located adjacent to the Basketball arena and Velodrome, swales and small balancing ponds have been implemented.
River Lea- swales, weirs, attenuation ponds
-Swales are included within the wetlands area to act as ‘slow the flow’ devices. They incorporate check dams (or weirs) at intervals to reduce velocities and provide open water features (attenuation ponds) alongside wetland pathways.
River Lea- rainwater harvesting
-Rainwater harvesting was installed at two permanent venues- the velodrome and copper box.
Strengths of SUDS in the River Lea
-The SUDS designed and installed within the park take account of the requirements of the environmental agency and take into account the potential impacts of climate change.
-They have increased the biodiversity of the area- the North Park wetland feature has become a wildlife haven for otters, kingfishers, grey herons and water voles.
-Much of the infrastructure involved recycling of the previous infrastructure and is carbon neutral.
-They have reduced sources of surface water contamination and increased interception and infiltration.
Limitations of SUDS in the River Lea
-One negative outcome has been the increased use of nitrogenous fertiliser to feed the newly vegetated areas, which has resulted in widespread eutrophication of watercourses.
