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Using Constructed Wetlands to Mitigate the
Impact of Diffuse Urban Pollution in the Salmons
Brook and Moore Brook Catchments
Wednesday 18th July 2018
Moore Brook catchment
•Area ~ 350 hectares
•8,000 residential properties
•300 misconnected properties
rectified since 2012
Pymmes Park Lake – major pollution events in November 2012 and March 2013
Pymmes Park Wetlands
•Total area ~ 5,000m2
•Wetland area ~ 2,000m2
•Volunteer planting in May 2015 organised by
Thames21
•600m2 of pre-planted coir mats installed in 2
days
May 2015
August 2015
Pymmes Park Wetlands
•Spoil used to create one new 11-aside football pitch and significantly improve a second existing pitch
•Area of 10,0000m2 raised by 0.7m
Pre-scheme During works
Firs Farm Playing Fields 21 hectares, 12 football pitches and 1 rugby pitch
Firs Farm Wetlands 30,000m3 flood storage, 2.4ha habitat enhancements including 4,000m2 wetlands, 600m long cycleway
Firs Farm Wetlands
•Wetland area ~ 4,000m2
•Volunteer planting in September 2015 organised by Thames21
•720m2 of pre-planted coir mats installed in 2 days
•Trees and shrubs planted in Autumn 2015
During construction (July 2015)
Following completion (June 2016)
Constructed Wetlands Slow the Flow
1. Glenbrook SuDS – 2014
2. Grovelands Park SuDS – 2014
3. Pymmes Park Wetlands – 2015
4. Firs Farm Wetlands – 2015
5. Bury Lodge Wetlands – 2016
6. Prince of Wales Wetlands – 2017
7. Broomfield Park Wetlands – 2018
8. Enfield Town Wetlands – 2018
1
6
7
52
3
4
Glenbrook SuDS
Bury Lodge Wetlands
Grovelands Park SuDS
8
Community Modelling
‘A way for local people to access the tools used by
scientists and authorities to manage environmental
problems’ Oxford University
Catchment
INCA – model
• Land use (Spatial)
• Weather – rainfall, temperature
• River Map/Network
Calibration
• Water quality readings – EA, Thames21
• Implementing constructed wetlands using observed field data
• Misconnections are assumed as effluent discharge
Constructed wetlands
Firs Farm – Ammonium DO%
Community Engagement
Potential Sites
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Period Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
mg/l
Ammonium
Simulated Scenario Good
28% reduction of ammonium if 16 wetlands across the catchment were created.
Water Quality Improvements – Catchment
Scale, Pymmes Brook