Natural Flood Management

The natural landscape has many capable mechanisms for storing and slowing flood waters. Natural Flood Management is the practice of enhancing and maintaining these mechanisms in order to reduce flood risk to human settlements.

The techniques have the potential to be effective, inexpensive, and beneficial beyond flood risk. However, there have been few real world case studies. To address this knowledge gap, in 2017 the UK Government published a comprehensive review of Natural Flood Management, and announced £15 million funding for Natural Flood Management schemes. Natural Flood Management features in the UK Government’s 25 Year Environment Plan, published January 2018.

You can read about Thames21’s Natural Flood Management projects below.

Flood Risk

Flooding to properties costs the UK an estimated £1.1 billion annually, with many billions worth more thought to be at risk. Total rainfall and intense rainfall events are expected to increase in the next few years, raising the risk of flooding.

Traditionally, installing hard engineered flood defences has been the preferred method for reducing flooding risk. This has prevented many areas from flooding. However, areas left at risk are often more complex to resolve and using hard engineering solutions on their own is increasingly proving less viable and cost prohibitive.

Instead, we must look to managing our catchments as a means to increase the resilience of our environment and society as a whole.

Natural Flood Management

Natural Flood Management strategies seek to work with nature to reduce the risk of flooding. Broadly, Natural Flood Management strategies fall into five categories:

  • Rivers and Floodplain management
  • Woodland management
  • Run-off management
  • Coast and estuary management
  • Urban Blue Green Infrastructure such as Sustainable Drainage Systems

Within these categories, there are different ways to help the catchment retain water, or slow its flow. Ponds, wetlands, and dips in the landscape can store water before it reaches the river network. Modified watercourses can be reconnected to their natural floodplains, where they can overflow harmlessly. Enhancements that slow floodwaters, such as leaky dams, help minimise the convergence of floodwaters lower in the catchment. Tree planting and soil management can increase soil’s capacity to absorb water.

Natural Flood Management practices not only alleviate flood risk, but can also benefit water quality, biodiversity, and carbon storage.

Thames21 and Natural Flood Management

From the government’s Natural Flood Management fund, Thames21 secured funding for four projects in North London, which are in the early stages of planning. These projects will take place on the Salmons Brook in Enfield, River Pinn Park Wood in Hillingdon, a headwater tributary of the Silkstream in Harrow, and a headwater tributary of the Rise Park Stream in Havering.

As part of these projects we will be funding a Natural Flood Management PhD based at Brunel University which will model and monitor the interventions. This will help guide their delivery and ensure that findings of these demonstration projects will be distributed to a much wider field. The knowledge built by Thames21 will help guide many future projects to reduce flood risk to people while improving the Environment for all.

For more information about Thames21’s work in Natural Flood Management, please email John Bryden, or call him on 07968 012828.