Greenwich Natural Flood Management (NFM) Project
What is NFM?
Natural flood Management (NFM) uses natural processes to reduce the risk of flooding. These processes protect, restore, and mimic the natural functions of rivers and floodplains to slow and store water. NFM can also provide wider benefits including enhanced habitats and biodiversity, improved water quality and availability of drinking water, carbon capture, and boosting health and well-being.
Project Summary
The Wickham Valley Watercourse, also known as the Wogebourne or Plumstead river, is an 8km tributary of the River Thames in the London boroughs of Greenwich and Bexley. It rises in Oxleas Woods and joins the Thames via Southmere Lake in Thamesmead. Its upper reaches are mostly above ground through woodland, farmland and fields. Its lower reaches are mostly underground within culverts beneath residential areas.
There are several issues affecting the river and leading to an increase in flood risk. This includes sediment blockages, lack of vegetation soaking up water, and straightened sections of the channel where water flows very quickly.
Greenwich Council and Thames21 are working to slow and store water on the Wickham Valley Watercourse across three woodlands – Oxleas Wood, Clothworkers Wood, and Bostall Woods. This will help reduce the risk of flooding in the area and improve local biodiversity. We will be using several NFM methods (see section below) to help restore the river.
Thames21 is also monitoring flow, water level and water quality across the Wickham Valley Watercourse throughout the project. This monitoring will help quantify the benefits of the project and improve national scale knowledge on NFM features and how they may contribute to flood risk reduction.
NFM Methods
Leaky Dams
Leaky dams are structures built across rivers or streams to help manage water flow. They are made from natural materials like logs, branches, or brushwood and have gaps that allow water to pass through slowly.
- Slowing water down: The gaps in the leaky dam slow the water, helping to reduce flooding by spreading it out and allowing it to soak into the ground.
- Storing water: These dams create small pools of water, storing water temporarily and reducing the amount that flows downstream all at once.
Berms
Berms are shelf-like mounds of earth, often built across the land or at the base of a river bank to help control water flow. They slow and direct water, helping to manage floods and improve the landscape for plants and wildlife
- Water storage: Berms can create small areas where water collects, allowing it to seep into the soil slowly instead of flowing away.
- Helping plants and soil: By holding water in place, berms help plants grow and improve the soil’s ability to absorb water, reducing erosion.
Ponds
Ponds are small bodies of water, either natural or man-made, that help manage water flow and support the environment.
- Storing water: Ponds collect rainwater and runoff, holding it in place. This helps prevent floods by reducing the amount of water rushing into rivers and streams all at once.
Construction
Royal Borough of Greenwich and Metis Consultants are finalising the locations for the leaky dams and other NFM features along the Wickham Valley Watercourse.
Works will begin in September/October to avoid bird nesting season. Thames21 will run six volunteering sessions a month from October until mid-March where we will be installing the NFM features. We would love for you to get involved.
Get Involved
We want you to be part of this project!
Take part in:
- River Improvement Days
- Citizen Science Days
- Woodland Walks
- Educational workshops
Click here to see upcoming events
Click here to join our WhatsApp group for project updates
Click here to view the linktr.ee for lots of useful information and resources
Email Toby (toby.dighero@thames21.org.uk) if you have any further questions
We would like to thank our partners for all their support. We are working in partnership with:
