Case study:Alma Road Rain Gardens
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- 1 Project overview
- 2 Image gallery
- 3 Catchment and subcatchment
- 4 Site
- 5 Project background
- 6 Reasons for river restoration
- 7 Measures
- 8 Monitoring
- 9 Additional documents and videos
- 10 Additional links and references
- 11 Supplementary Information
|Project web site|
|Themes||Environmental flows and water resources, Flood risk management, Habitat and biodiversity, Social benefits, Water quality, Urban|
|Main contact forename||Jamie|
|Main contact surname||Kukadia|
|Main contact user ID||User:London Borough of Enfield|
|Contact organisation||London Borough of Enfield|
|Contact organisation web site||http://enfield.gov.uk/|
|Partner organisations||Thames 21, Greater London Authority|
|Parent multi-site project|
| This is a parent project
encompassing the following
Alma Road is situated in Ponders End, a deprived area in the London Borough of Enfield. The area is known to suffer some localised surface water flooding, due to the impermeable nature of the surroundings created by the expanse of hard-surfaces, lack of green spaces and inadequate capacity in the existing drainage system.
This part of Enfield is generally low lying, as it forms part of the Lee Valley. The natural flow path to the nearby watercourse, Brimsdown Ditch, a tributary of the Salmons Brook/River Lee, is obstructed by the adjacent railway line and exacerbates surface water flood risk. When it rains the runoff from Alma Road picks up a large amount of pollutants, drains into the highways gullies and is fed into the Brimsdown Ditch.
Rain Gardens are a type of Sustainable Drainage (also known as “SuDS”) which mimics natural drainage by allowing water to soak naturally into the ground.
The project will retrofit five Rain Gardens into the highway realm, with a total area of 200m2 along a 200m stretch of Alma Road, with the aims of:
• Reducing surface water flood risk on the highway, as highlighted in the London Borough of Enfield’s Local Flood Risk Management Strategy (2015) • Water quality improvements to surface water runoff and the receiving Brimsdown Ditch by removing runoff from the conventional drainage system • Improving biodiversity by planting a wide variety of species • Horizontal traffic management by slowing down traffic in proximity to the school, bus stop and several wide junctions that are currently not pedestrian-friendly • Aesthetic enhancement of the road and the surrounding area • Improving public perception of SuDS through school and community engagement. • Inspiring more green infrastructure SuDS development across the borough
In later phases, the Alma Road Rain Gardens will be complemented by an additional 400m of SuDS features along the highway and across the 7Ha site of the Alma Regeneration Project.
Monitoring surveys and results
The functionality of the Rain Gardens will be monitored by the Structures and Watercourses team from the London Borough of Enfield during and after rainfall events, and during dry weather spells.
Local perception of Sustainable Drainage Systems is also being noted. Alma Primary School have been particularly perceptive to the project and have engaged their pupils in "River" sessions with Thames21. As a result, the Primary School are keen to employ their own SuDS features within the school premises, and have already retrofitted several Thames21 Rainplanters intercepting roof runoff.
Catchment and subcatchment
Select a catchment/subcatchment
Other case studies in this subcatchment: Bury Lodge Wetlands, Enfield Town Park Wetlands, Glenbrook Wetlands, Grovelands Park Wetlands, Houndsden Road Rain Gardens, Laymer Road Silt Trap and Recreational Ground, Rewilding Enfield's Urban Rivers, Salmons Brook Flood Alleviation Scheme, Montagu Recreation Ground site, Salmons Brook River Restoration at Laymer Road, Salmons Brook at Grange Park
Cost for project phases
Reasons for river restoration
Hydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Additional documents and videos