Water quality and flood risk

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Draft webpage: To be finalised during consultation.

What we need to do and where

1. About

Water quality and flood risk are hugely important services provided by nature, and across much of Devon these services are under great pressure. They are impacted by the way we manage the land, by the way we treat our wastewater and source our drinking water and by the run-off from our roads and settlements; and all of these impacts are intensified by climate change.

In a fully natural system, much of the water that falls on the land as rain, is absorbed by the soil and either filters deep underground to be stored in rock formations, or flows gently through the soil, finally reaching streams and rivers. Naturally-functioning river floodplains also absorb excess flows in a complex system of wetlands and multiple shallow channels that readily spill floodwaters onto the surrounding land.  These natural processes slow down the water (known as natural flood management – NFM) and filter out impurities at the same time.

Devon has a large and growing population of wild-living beavers. This species, returning after a 400-year absence to England and now a protected species, is one of nature’s “ecosystem engineers”. Beavers build dams to protect access to their lodges and feeding grounds and these dams help form natural wetlands that store and purify water as well as boosting biodiversity.

The diagram below shows some typical NFM interventions and the following film shows some of these in action. In general, the first priority for NFM and for water quality improvements is to improve soil management so that more water infiltrates into the ground. Creating more natural habitats on the surface is the next priority because these tend to slow floodwaters down through natural roughness. Reconnecting floodplains and other water storage techniques are also very valuable.

https://thefloodhub.co.uk/wp-content/uploads/2021/11/NFM-catchment-picture.png (To be inserted)

We rely on these natural systems to help absorb the impact of heavy rainfall and reduce flood risk, and to help filter out pollution so that water becomes drinkable without vastly expensive treatment and our rivers are safer to bathe in.

Well-managed, expanded and better-connected wildlife-rich habitats can help to repair and deliver these critical ecosystem services.

The LNRS aims to maximise the benefits of natural flood management and other ecosystem services, but it’s important to note that nature alone can’t solve all our problems. Improved sewage treatment, improved water supply networks, hard flood defences and reduced pollution at source all remain essential tools to protect nature and human health and wellbeing.

Health check

Flooding has huge impacts on property and people’s wellbeing, as well as on wildlife.

Poor water quality not only impacts on wildlife but also affects human health, when we bathe in rivers and when we extract drinking water from rivers and ground water.

Some stats needed here on increasing flood events / damages; plus water quality problems affecting drinking water.

Key pressures and opportunities

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Habitats

In our heavily modified landscapes naturally functioning soils and floodplain systems are in short supply. This is mainly because of the loss of habitats, the compaction of many areas by high levels of livestock, the use of heavy machinery, and covering with concrete or tarmac. This means a large amount of any rain falling tends to run over the surface, carrying pollutants with it that impact on water quality in our ponds, lakes and rivers. At times of high rainfall this surface water run-off can rapidly reach rivers where it gathers in force.

Restoring, expanding and connecting habitats so that they create better-functioning ecosystems is the key opportunity.

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River channels

Historic efforts to reduce flooding by straightening and deepening river channels mean that floodwaters can’t spill out onto the floodplain as they once did and most of the original floodplain wetland systems have been removed. The result is that water is sent even more rapidly towards the large urban centres that are often built low down the river system, often causing damage through flooding.

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Climate change

Climate change is a major pressure on our rivers and water resources. More intense rainfall events mean that flooding is more likely and longer; more intense droughts mean that periods of low flows are more likely.

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Pollutants

Many different pollutants can enter our watercourses and affect water quality. These include phosphates, nitrates, chemicals (including pesticides, herbicides, fungicides, solvents, metals, and pharmaceuticals), microbial pathogens, dissolved organic carbon and sediments. The emergence of novel chemicals is a growing issue of concern. The Environment Agency is tackling these pollution sources through regulation and advice to industry.

2. What we need to do and where

Priority

Manage, restore and create wildlife-rich habitats and ecosystems to help meet water quality, water resources and flood risk targets across Devon.

Actions

Every river in Devon suffers from some degree of pollution and every resident, business, landowner and manager in the county can take steps to prevent pollutants reaching our rivers. Likewise, flooding is an issue affecting many people in Devon and wherever we can slow the flow of water, the more this risk reduces and wildlife benefits.

Natural Flood Management (NFM) techniques like improved soil infiltration, new wetlands, leaky dams and floodplain re-connection (see Diagram and video above) are increasingly being adopted as a way of reducing flood risk, although these typically have most benefit in smaller catchments.

The LNRS aims to restore and expand natural habitats across much of Devon; wherever this happens the results will be better-draining soils resulting in improved water quality and reduced flood risk. Woodland creation, wetland creation and farming techniques that improve soil infiltration are particularly effective interventions.  

Reduce pollution

  • Everyone across Devon can take steps to prevent water pollution. See Actions on the Watercourse corridors page.

Manage, restore and create wildlife-rich habitats to store water, slow water flows and help absorb pollutants

  • Managing and restoring all wildlife-rich habitats (particularly soils) can slow flows and improve water quality, see actions on the Habitats pages.  However, to know which habitat will be most beneficial in any situation requires expert advice, see links in Find out more.

Where we need to focus action

Actions are needed across Devon to reduce pollution and slow flows.  However, to help meet priorities relating to drinking water and flood control, actions are prioritised to the following areas. See Mapping for the LNRS Viewer and Mapping Methodology.

Drinking Water Safeguard Zones for Surface Water and Ground Water. In these areas any actions that limit pollution, improve infiltration and store water will be highly beneficial.

Natural Flood Management high priority catchments. This identifies the communities in Devon that have the highest exposure to a risk of flood damage and then assesses where NFM can have the most benefit. In these areas actions that improve infiltration and water storage will be highly beneficial.

Beaver Priority Catchments are also mapped to show where beavers are already present in the wild. Where these overlap with NFM high priority catchments, beavers are likely to be able to provide significant NFM benefits.

Deciding which type of NFM will be most beneficial is something that can only be determined following field survey and detailed discussion with an expert.

3. Inspiration

Case studies

There is a huge amount of NFM work underway in Devon. Here are a few examples:

The Dartmoor Headwaters project

The Dartmoor Headwaters project is delivered by Dartmoor National Park, the Environment Agency and Devon County Council. It focuses on the headwaters of several Dartmoor rivers to reduce flood risk in towns downstream, using NFM.

The Climate Resilient Otter Catchment

The Climate Resilient Otter Catchment (CROC) Project, funded and led by the Environment Agency, is supporting farmers and landowners in the River Otter catchment to enhance the condition of their soils, improving the ability of soils to soak up water and reduce flood risk following intense rainfall events.

Work to improve water quality is also a major area of activity by public, private and voluntary bodies across Devon. Some examples are:

South West Water is delivering Upstream Thinking, a major programme to improve water quality in our rivers and seas.

Friends of the Dart working to designate bathing waters and focus on water quality improvements.

4. Find out more

More useful links to be added during consultation.

The Environment Agency, Natural England and the Forestry Commission can provide further advice. Many other organisations also employ farm and wildlife advisors who may be able to support.

Devon County Council’s flood risk team have published useful guidance on NFM.

https://www.gov.uk/flood-and-coastal-erosion-risk-management-research-reports/working-with-natural-processes-to-reduce-flood-risk-2024

Devon and Cornwall Natural Flood Management Studio Dashboard – useful to assess potential NFM measures but do back this up with site surveys and expert input. https://atkinsgeospatial.maps.arcgis.com/apps/MapSeries/index.html?appid=ed51f0997bee4576b83e851600bbddda

https://environment.data.gov.uk/farmers/ shows the Drinking Water Safeguard Zones. For each Zone, you can download an Action Plan that describes the reasons for its designation and the actions needed – just click on the Zone in the map.  

The Connecting the Culm project is focused on reducing flood risk in the Culm catchment using NFM. A key target is to reduce the risk of closure of the main railway line to the region, which is currently flooded on average once a year.  

The Devon Resilience Innovation Project (DRIP) is funded by the Environment Agency and is usig NFM, alongside other measures, to reduce the risk of flooding in “rapid-response” flash flooding locations across Devon.

Westcountry Rivers Trust Citizen Science programme provides training for volunteers in water quality testing.  

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