Natural flood management (NFM) involves using various techniques to restore or mimic the natural functions of rivers, floodplains, and the wider catchment. It aims to store water in the catchment and slow the rate at which water runs off the landscape into rivers, to help reduce flood risk to communities downstream. NFM is also referred to as ‘working with natural processes’, ‘slow the flow’, ‘sustainable land management’ or ‘upstream management’.
Natural flood management (NFM) is becoming more commonly used across the country to try and help manage flood risk.
It is important that NFM measures are used as part of a combination of techniques that work together to provide flood mitigation, rather than relying on natural features alone. They can be used alongside existing ‘hard’ defences, as increasing the height of a wall or embankment alone does not always provide the best or most sustainable long-term solution.
Image taken from the National Flood and Coastal Erosion Risk Management Strategy for England showing the different Natural Flood Management Techniques
The North West ‘Natural Flood Management measures – a practical guide for farmers’ handbook contains more information about the types of NFM techniques that landowners can use, the associated maintenance and costs, and extra considerations.
You can take a look at our ‘Your Local Area’ page and map to see projects in your area and across the North West that are using NFM to help to manage flood risk.
The Environment Agency ‘Using the power of nature to increase flood resilience‘ report explains the benefits of the Natural Flood Management Programme and celebrates its successes.
The Environment Agency working with Lancaster University are undertaking a number of pilot projects which includes a pilot in the Kent catchment to evaluate the effectiveness of nature based flood mitigation. Watch the video below to find out more.
The Online Marine Registry (OMReg) website includes a map of coastal projects happening in the UK and across the world. Various shoreline schemes are displayed on the map and in the database, including coastal NFM schemes involving techniques such as managed realignment and shoreline restoration. Click here to explore the OMREG website.
All the resources of the different natural flood management techniques featured on this page can be found in our Natural Flood Management Toolkit which can be found here.
The Coastal Natural Flood Management Toolkit can be found here.
This involves restoring river channels to a more natural route to slow the flow of water and allowing rivers to reconnect to their floodplains and increase floodwater storage upstream. Many rivers have been straightened, or embankments have been built adjacent to channels to increase the amount of land available for agriculture. As a result, the river is unable to flood the adjacent land (the floodplain) and instead flows quickly downstream to communities, increasing their flood risk.
There are many benefits to river and floodplain restoration, these Include:
Download the resource for more information here.
© David Dixon / Ribble Valley Flood Plain from the Viewpoint at Brockholes Nature Reserve / CC BY-SA 2.0
Structures made with natural materials, such as leaky woody dams and boulders, can be used to attenuate water and encourage the flow of water out of the stream on to floodplains or flood storage areas in periods of high flows. They reduce maximum flood peaks by increasing the amount of time it takes for rainwater to flow downstream. They can also help to collect debris to prevent blockages further downstream at pinch points.
They are often designed to replicate naturally fallen trees and create a variety of different habitats and flow conditions. By sitting above normal stream level, fish movement is not affected.
There are many benefits of installing leaky woody dams, such as:
Download the resource for more information here.
West Cumbria Rivers Trust / Leaky Dam in Dovenby, Cumbria
Tree planting and woodland creation is effective at reducing flood risk by intercepting rainfall before it reaches the ground. This minimises surface water runoff and the volume of water entering watercourses, which reduces flood risk.
The benefits of tree planting are more long-term but can:
Download the resource for more information here.
© Kay Atherton / New tree planting at Ervey wood / CC BY-SA 2.0
FACT: Trees can reduce the amount of water reaching the ground by 24-45% for conifers and 10-25% for broadleaves. – Natural Flood Management Measures: A practical guide for farmers.
Many of the UK’s moorlands have been heavily eroded due to pollution, overgrazing of livestock and draining land for agriculture. Bare and heavily eroded peat on moorlands can be stabilised with heather brash, grasses and fertiliser, whilst planting sphagnum moss adds an effective building block for peat formation and reduces CO2 in the atmosphere. Gully and grip blocking also slows the slow of water and raises the water table. The healthy peat can store up to 20 times its weight in water, minimising runoff into watercourses and reducing flood risk. Peat also increases surface roughness which slows the flow of water over the land.
Benefits of moorland restoration include:
Download the resource for more information here.
Geograph / Moorland restoration
This technique involves growing and harvesting willow to increase infiltration and evaporation, reducing the volume of flood water reaching the ground and entering watercourses. Willow is an energy crop that is harvested every three years and can also provide a source of income for farmers.
There are a number of benefits to this natural flood management technique:
© M J Richardson / Willow Plantation / CC BY-SA 2.0
The storage of floodwater upstream can reduce flows further down the watercourse to ease flooding downstream. An outlet structure would be used to hold floodwater during high river levels and return it to the river once the flood peak has passed. There are two types of flood storage; online storage and offline storage: Online storage is the temporary storage of water within the river channel and its floodplain, whereas offline storage is when water within the channel is diverted using an intake structure and held in a separate storage area situated on the floodplain.
Benefits of flood storage:
Download the resource for more information here.
Online storage
Offline storage
The management of agricultural land can be tailored to aid upstream management by using techniques that increase the land’s capacity to store water. The main aim is to reduce soil compaction and improve soil quality so that it can hold more water and reduce the amount that enters watercourses. Some of the techniques include machinery practices that can help to reduce soil compaction, such as by minimising loads and using flexible tyres on weak or saturated soils, or runoff control, such as contour cultivation across fields instead of up and down to reduce surface water runoff. This will help to ease the impact of flood events and reduce the risk of flooding in the future.
The benefits of agricultural land management include:
Download the resource for more information here.
FACT: Runoff from compacted soils is 50-60% higher than on aerated healthy soils. (Agriculture and Horticulture Development Board, 2016) – Natural Flood Management: A Practical Guide for Farmers
Land managers should be aware of soil management rules that they need to follow. Find out more about these rules here.
© N Chadwick / Nidderdale Way along the River Nidd / CC BY-SA 2.0
Coastal schemes are often large scale and use expensive hard engineering methods to help manage coastal flooding and erosion. Coastal natural flood management (NFM) uses natural materials and methods to reduce wave energy and the risk of coastal flooding and erosion. Find out more about the different types of coastal NFM below.
Our ‘North West Coastline’ page highlights schemes that have been completed along the North West coast. This includes both hard engineered schemes and those using natural flood management measures, with links to more information about them.
Sand dunes along coastlines provide a natural defence against coastal erosion and flooding. During storms, waves crash against sand dunes and slowly erode them, as opposed to eroding the coastline or flooding infrastructure and property. The sand that is lost is replaced by windblown sediment. The three main techniques to help protect the dunes, trap sediment and prevent excess erosion are fencing, planting and thatching. Pine trees can be used to restore sand dunes without an environmental permit if certain conditions are complied with.
Benefits of dune regeneration include:
Download the resource for more information here.
© Trevor Harris / Dunes at Formby Point / CA BY-SS 2.0
Replacing material on the beach which has been lost from sea or wind erosion can help protect the local community from coastal flooding as well as maintaining the natural appearance of the beach. Methods used to collect and replenish beach material include dredging, reprofiling and the transportation of material quarried from an area inshore. The benefits of this technique are seen in the short term as the material may erode repeatedly and therefore would need to be replenished repeatedly.
Benefits of beach nourishment include:
Download the resource for more information here.
© Peter Home / The Beach at Cley, Norfolk / CC BY-SA 2.0
This is the planned breach or relocation of sea defences further inland which creates sustainable, environmentally beneficial intertidal habitat in the form of salt marshes or mud flats. These coastal marshes help to dissipate wave energy and protect against erosion and flooding. This method is a more natural alternative to building higher sea walls or other defences.
Benefits of managed realignment include:
Download resource for more information here.
Construction phase of Hesketh Out Marsh West in the Ribble Estuary, Lancashire
As well as managing and reducing flood risk, there are various other advantages to using NFM techniques in a catchment. They provide a range of benefits to people and the environment, from providing public amenities to increasing biodiversity.
Click here to download this ‘Multiple benefits of Natural Flood Management’ resource.
Making small adjustments to your land management or allowing unproductive land to be used for flood storage can make a big difference to those in your community who are at risk of flooding further downstream. Landowners can work together to implement NFM measures and help to manage flood risk locally, empowering the community to resolve their local issues.
An increase in green spaces such as woodlands allows for more recreational activities to take place, such as walking and mountain biking, which improves health. NFM counteracts the loss of green spaces in urban areas and improves quality of life by providing safe and aesthetically pleasing environments.
There is also the opportunity for some measures such as wetland creation and river restoration to be used as tools for education, recreation and tourism. All of these benefits can increase the availability of jobs.
By implementing NFM techniques on your land you can gain financial benefits, such as through the Countryside Stewardship scheme. This scheme offers grants for land managers to adopt capital items or management options such as instream structures or riverbank restoration. Facilitation funds may also be available in your area to assist with your application and these can provide a 10-20% uplift to your score. For more information about the financial incentives and funding available, visit our Landowner page here.
Most NFM techniques have additional benefits for wildlife and biodiversity. Creating wetlands, which are one of the most biologically diverse ecosystems, not only increases biodiversity but can also improve the connectivity between multiple wetland habitats and ease the movement of plants and animals between them. Restoring rivers improves fish habitats and creating woodland provides a habitat for wildlife.
Creating woodland and using less intensive soil management techniques both improve the structure of soil by increasing the rate of infiltration and reducing runoff. An improved soil structure means reduced siltation and less sediment entering rivers and watercourses, which in turn improves the quality of rivers, lakes and other bodies of water under the Water Framework Directive (WFD).
Offline storage areas can help with sediment capture, preventing the loss of sediments into the watercourse. Creating woodland and managing soil less intensively reduces topsoil erosion and improves soil structure, which can also reduce the amount of sediment entering watercourses. Other methods that can reduce sediment loss are blocking drainage channels so sediment is retained in the land and reconnecting wetlands which can manage high nutrient loads and reduce siltation downstream.
The creation of woodlands and wetlands (e.g. peatland, floodplains and salt marshes) can help the ecosystem become more resilient to the effects of climate change. These types of land are efficient at carbon sequestration which results in the removal of carbon dioxide from the atmosphere, such as via sphagnum moss in peatland. Agricultural land management techniques such as contour cultivation reduces surface water runoff and soil erosion and helps to reduce the loss of carbon from soil.
NFM techniques can reduce erosion at the coast and inland at rivers and ordinary watercourses. Salt marshes and mudflats help to reduce wave energy at shorelines and sand dunes act as a natural buffer for cliffs from waves, reducing the rate of erosion. Beach nourishment restores the natural coastal defence function and sediment processes of beaches. Erosion of riverbanks and other watercourses is reduced via measures such as planting buffer strips on the banks which increases soil stability.
Click on the links below to download the Natural Flood Management (NFM) case studies which showcase great examples of how NFM can help reduce flood risk and provide multiple benefits across the North West.
Wetlands are a sustainable solution to managing flood risk as they are able to slow and store surface run-off following heavy rainfall. The variety of vegetation found in wetland areas create obstacles which intercept rainfall, and a suitable ground which rainwater can infiltrate, both of which slow the flow of water down catchment. Wetlands also create ecosystems which are effective at filtering and cleaning wastewater. This in turn, improves the quality of water, making them an effective approach used by United Utilities when treating wastewater.
Ensuring the effective management of woodlands can increase the effect they have on flood risk and water quality. Woodlands act like a sink which soaks up large volumes of water infiltrating into the ground, and therefore reducing the amount of surface water run-off. The large canopies found in woodlands are able to intercept rainfall as it’s falling, and due to the uneven ground in woodland which is caused by vegetation, shrubs and tree roots, the flow of water is slowed. This has a positive effect by increasing the lag time seen between peak rainfall and peak flow in rivers further down the course.
Peatlands are valuable ecosystems which when healthy, are home to a wide range of species from insects to birds of prey. They can store vast amounts of carbon, and due to their water-storing capacity, they are able to reduce flood risk further down the catchment. United Utilities are working to return the peatlands to their natural state which will create a sustainable flood risk management approach. Peatlands are effective at slowing the flow of water and increasing the time between peak rainfall and peak run-off due to the dense vegetation, such as sphagnum moss.
Centre of Expertise for Water (CERW) Report – Communities at Risk of Flooding and their Attitudes towards Natural Flood Management (NFM)
