Author:  Peter Williams

Starting life in the Blackdown Hills, the River Otter flows 40 miles through classic Devon landscapes, winding its way to emerge on the Jurassic Coast at Budleigh Salterton. With just two small towns and a few villages along the route, the Otter should epitomise England’s ecologically rich and diverse river habitats.

Unfortunately, the Middle and Lower sections of the River Otter are both classified by the Environment Agency (EA) as ‘Poor Ecological Status’.  This is the second lowest of the five water quality designations and indicates that there are significant impacts on plant life, wildlife and fish. 

This places the River Otter in the worst 20% of the UK’s river systems.

The Environment Agency (EA) identify the main pollutant types & key sources: 

• Sewage discharges coming from South West Water’s (SWW) sewage systems
• Pollution from ‘Agriculture and Land Management’, specifically livestock, soil and nutrient management. These are defined as ‘Diffuse’ in nature.

Our first objective for this project is to identify the relative ecological impact of SWW’s sewage discharges compared to agricultural run-off, and identify specific locations or general areas causing the greatest harm. 

We plan to achieve this through a structured program of water quality testing, using both automated systems and Citizen Science volunteer testers. 

Achieving this, and supported by a credible data set, would help us to: 

• Focus SWW on addressing specific polluting assets
• Identify sections of river where the most agricultural pollution is occurring and work with partner organisations to help improve land management

What we know already: South West Water sewage discharges 

In 2023, South West Water discharged untreated sewage into the Otter on at least 830 occasions for a total of 6,391 hours. That’s 3x times the total sewage hours dumped into Exmouth Bay. In fact, the real total is likely to be closer to 8,000 hours, as the monitor at Honiton sewage works (which discharges the most untreated sewage into the river), was broken for the first 6 months of the year.

SWWs top five polluting assets discharged 88% of the total sewage into the river Otter, mostly within a six mile stretch of the middle Otter between Honiton and Tipton. Whilst this demonstrates just how bad those assets are, it does indicate the potential for South West Water to dramatically improve their sewage discharge record, if they can focus resources on improving those five units.

Recent research by the University of Oxford indicates sewage discharged into rivers has a greater impact on water quality, and the animals and plants that live in rivers, than surrounding agricultural land use.

Key findings of the Oxford University report include:

• Sewage pollution was found to be the primary driver of increased nutrients (including phosphates), algae, and sewage fungus in rivers.
• Sewage discharge also radically altered plant, animal, and microbe communities, increasing the abundance of harmful species.

To help people visualise the problem and locate the SWW overflows, we have created an interactive public Google map showing each EDM location, and adding the specific amount of sewage discharged in 2023. Each EDM unit is also colour coded with a RAG status, Red for Poor through Green for those units which have not discharged in 2023. 

You can find the map by clicking this link ( here ): 

What’s next? 

We need to fully develop our plans on test locations and methods, and we will be validating the program with experts before launching the project.  In the meantime, if this sounds like something that you would like to be involved with, please get in touch.