Coney Gut is classified as Moderate Ecological Status, but note this is an elevated classification because it is a "heavily modified waterbody" and some parameters are Poor. The failing elements are ammonia, phosphate, phytobenthos and invertebrates, indicating a combination of nutrient enrichment and organic pollution pressures. The invertebrate ASPT score is 0.665, below the Good threshold of 0.86, while phosphate is 0.181 mg/l against a Good threshold of 0.043 mg/l. Ammonia is also failing.
The evidence points strongly towards wastewater as the primary pressure. The Environment Agency has identified continuous sewage discharges as an RNAG. Phosphate source modelling attributes approximately 77% of phosphate loading to continuous discharges, while the detailed source model attributes around 75% to South West Water sewage treatment works, compared with approximately 15% from livestock. Coney Gut is also one of the most urbanised catchments in North Devon, with 22.6% urban land cover, 4,738 properties on mains sewerage and 4,817 properties on private sewerage.
Coney Gut is also one of only two heavily modified water bodies in the catchment. Urban and transport pressures, flood protection structures and channel modification are therefore likely to contribute to the ecological response alongside nutrient pressures.
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Eco Class Good Moderate Poor Bad
Catchment Ranking: 77/92
Catchment Ranking
The ranking is derived from the EA 2025 classification data. Parameter scores are normalised and an average is taken. Rankings are restricted to prevent e.g. a "moderate" river being ranked higher than a "poor" river.
(92 river waterbodies in the North Devon Catchment)
EA Ecological Classification
- 2022Moderate
- 2019Moderate
- 2016Moderate
Failing Elements
- Ammonia (Phys-Chem)
- Invertebrates
- Mitigation Measures Assessment
- Phosphate
- Phytobenthos Sub Element
EA RNAGs
- Flood protection
- Flood protection - other operational management
- Other (not in list, must add details in comments)
- Poor Livestock Management
- Sewage discharge (continuous)
Coney Gut
Why is the river failing?
What is happening now?
Current activity includes review of discharge permits, regulatory farm inspections, mitigation of urban drainage outfalls, investigations to determine appropriate measures, and delivery of Devon Woods projects.
Risk Levels
Risk Levels
- SWW Overflows: Total duration of intermittent spills for all CSOs in the catchment for 2025.
- Private Sewage: Density rating based upon non-SWW properties in the catchment.
- Livestock: APHA data from Feb 2026.
- Runoff: ESME modelling (wf_r24).
- Modification: ESME modelling (aa_r1).
- Invasive Species: ESME modelling (iv_r17).
- Overheating: derived from tree cover ESME modelling (wq_r10).
- Running Dry: Abstraction sustainability ESME modelling (ws_r27).
- Untreated SewageVery Low
- ModificationMedium
- Sewage (Private)Very High
- Invasive SpeciesLow
- LivestockMedium
- OverheatingLow
- RunoffHigh
- Running DryLow
Intervention hypothesis (confidence: High)
Coney Gut is one of the clearest wastewater-driven water bodies in the catchment. Failing ammonia, phosphate, phytobenthos and invertebrates are all consistent with nutrient enrichment and organic pollution pressures. The phosphorus source modelling, RNAGs and existing measures all point in the same direction, with continuous sewage discharges representing the dominant source of phosphorus loading.
The primary focus should therefore be reducing nutrient inputs from continuous wastewater discharges. Urban runoff and livestock pressures are likely to be important secondary pressures but appear materially smaller than the wastewater contribution. Given the heavily modified nature of the water body, expectations for ecological recovery should also recognise the structural constraints within the catchment.
| Intervention | Size of Intervention | Estimated Cost | Lead |
|---|---|---|---|
| PRIORITY INTERVENTIONS (NOT IN ORDER OF PRIORITY) | |||
| Investment in STWs (phosphate reduction) | AMP9 | £3m | SWW |
| SECONDARY INTERVENTIONS | |||
| Private sewerage awareness & improvement programme | £10,000 | tbd | |