13. Glenbrook Wetlands
Themes: Water quality; Biodiversity
Objectives:
- Reduce the frequency and severity of pollution
- Increase surface water management at source
Project description
The Glenbrook is a tributary of the Salmons Brook. It flows through underground ppipes for much of its length. Hidden away it is damaged, and when it first emerges above ground it is already badly polluted. Six linked wetlands have been created here to filter pollutants from the stream.
The flow is directed through each wetland, being successively cleaned as it is slowed through the basins. Plants use nutrients such as phosphate and nitrate to grow, removing them from the water and stopping them polluting the stream. Bacteria in the soil and root systems break down oils and heavy metals. Once established the planted wetlands not only clean the water, they also add a new dimension to the habitat mosaic for wildlife, and give interest and colour for those passing by.
Thames21 has been working with EnfieldCouncil, the Environment Agency and Thames Water to improve the health of the Salmons Brook and its tributaries. Enfield has a seperate sewage system, meaning that surface water eeg. rain running off roads and wastewater are carried in two seperate pipes. As a result, pollutants enter the Salmons Brook in a number of different ways. MIsconnected plumbing contributes to nutrients such as phosphates and nitrates, road run-off inputs oils and heavy metals such as zinc and copper, and household and industrial waste is dumped into surface water drains.
With great support from local people we've created Sustainable Drainage Systems (SuDS), or 'rainscapes'. These are watery landscapes inspired by nature which intercept the pollution and stop it from getting into our rivers and streams. As well as filtering pollutants out of water, SuDS can also help reduce local flood risk by slowing the flow, create wildlife habitats and provide new amenities for local people.