Water quality and flood risk

Version 1

Draft webpage: To be finalised during consultation.

What we need to do and where

Waterfall near Vennford, Annie Houston

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. 

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. 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 and filter out impurities at the same time.  

We rely on these systems to absorb the impact of heavy rainfall and reduce flood risk, and to filter out pollution so that water becomes drinkable without vastly expensive treatment. 

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

Health check

Flooding has huge impacts on property and people’s wellbeing.  

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. More intense rainfall events mean that flooding is more likely and longer, more intense droughts mean that periods of low flows are more likely.

2. What we need to do and where

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. These are outlined in our Actions for Watercourses.    

Natural Flood Management (NFM) techniques like improved soil infiltration, new wetlands, leaky dams and floodplain reconnection 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 regenerative farming techniques are particularly effective interventions. 

Where to focus action

Some areas of Devon are at greater risk from flooding and poor water quality. In these areas, actions to reduce flood risk and improve water quality will have a high level of benefit for people and communities. These areas are shown on the LNRS Map under “Other useful layers”.  In these areas there is more likely to be funding available to deliver flood risk and water quality actions.

Water quality

For water quality, the EA and SWW have identified areas that are important for drinking water extraction. These are 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.  

Several of these Drinking Water Safeguard Zones overlap with Full Restoration Rivers that have the greatest potential to be restored to High or Good ecological condition. Doing so will improve their water quality and supply volume alongside other outcomes.

Flood risk

For flood risk reduction, the EA’s Natural Flood Management priority mapping 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. 

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.   

We have also identified Beaver Priority Catchments where beavers are already present in the wild. Where these overlap with NFM priority areas, beavers are likely to be able to provide significant NFM benefits.

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.

Connecting the Culm

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.

Devon Resilience Innovation Project

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.

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

Westcountry Rivers Trust Citizen Science programme.

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

South West Water is delivering a Water Fit programme to improve water quality in our rivers and seas.

4. Find out more

Consultation Q: Can we reference the EA to get advice?

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.

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.  

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