Mole (Source to Burcombe Stream) is currently at Moderate Ecological Status. The principal failing element is phytobenthos, with an EQR of 0.562, below the Good threshold of 0.60. Fish are achieving Good status (EQR 0.595), invertebrates are High status physico-chemical indicators are High except for Phosphate which is Moderate, but very close to Good status. The river therefore exhibits relatively limited ecological impairment beyond nutrient response indicators.
The Environment Agency has identified continuous sewage discharges as the sole RNAG. Phosphate source modelling attributes approximately 43% of phosphorus loading to South West Water assets, with a similar proportion derived from livestock sources. The detailed source model attributes around 43% to sewage treatment works and 46% to livestock, producing one of the more balanced agricultural/wastewater nutrient profiles in the Mole system.
The catchment contains 53 farms and remains predominantly rural. Existing measures already include farm inspections, permit review work, Devon Woods and the Mole Maize Project, indicating that both agricultural and wastewater nutrient sources are already recognised.
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Eco Class Good Moderate Poor Bad
Catchment Ranking: 39/92
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
- Phytobenthos Sub Element
EA RNAGs
- Poor Livestock Management
- Sewage discharge (continuous)
Mole (Source to Burcombe Stream)
Why is the river failing?
What is happening now?
Current activity includes regulatory farm inspections, review of discharge permits, Devon Woods and delivery of the Mole Maize Project.
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 SewageHigh
- ModificationMedium
- Sewage (Private)Very Low
- Invasive SpeciesHigh
- LivestockMedium
- OverheatingLow
- RunoffMedium
- Running DryVery Low
Intervention hypothesis (confidence: Med-High)
This appears to be a relatively balanced nutrient-management water body. The phytobenthos failure suggests nutrient enrichment, but fish, invertebrates and physico-chemical indicators remain strong. The available evidence suggests that neither agriculture nor wastewater alone fully explains the failure.
The most plausible recovery pathway is therefore to continue addressing both pressures simultaneously. Existing farm-focussed measures should remain the primary intervention because of the scale of agricultural activity within the catchment, while permit reviews should ensure that continuous wastewater discharges are not preventing recovery.
| Intervention | Size of Intervention | Estimated Cost | Lead |
|---|---|---|---|
| PRIORITY INTERVENTIONS (NOT IN ORDER OF PRIORITY) | |||
| Investment in STWs (phosphate reduction) | £3m | SWW | |
| Investment in storm overflows (reduction in spills) | AMP9 | £7m | SWW |
| Regulatory enforcement to drive compliance with Farming Rules for Water | c.14 priority farms | £28,000 | EA |
| Poultry manure management support | c.4 priority farms | £100,000 | To establish |
| Soil health interventions | c.14 priority farms | £392,000 | NE/DWT/WRT/EA |
| SECONDARY INTERVENTIONS | |||
| Riparian tree planting | 4.3km (17.2km) | £86,000 | ND Biosphere Foundation |