Colne (Confluence with Chess to River Thames) Water Body
Moderate ecological status
Get Colne (Confluence with Chess to River Thames) data
Attributes
- Water Body IDGB106039023090
- Water Body TypeRiver
- Hydromorphological designationheavily modified
- NGRTQ0459793541
- Catchment area89.316 km2
- Surveillance Water BodyNo
- Catchment area8931.645 ha
- Length51.489 km
Classifications
| Classification Item | 2019 | 2022 |
|---|---|---|
| Ecological | Moderate | Moderate |
| Biological quality elements | Moderate | Good |
| Fish | Good | Good |
| Invertebrates | High | High |
| Macrophytes and Phytobenthos Combined | Moderate | Good |
| Macrophytes Sub Element | Moderate | Good |
| Physico-chemical quality elements | Moderate | Moderate |
| Acid Neutralising Capacity | High | High |
| Ammonia (Phys-Chem) | High | High |
| Biochemical Oxygen Demand (BOD) | High | |
| Dissolved oxygen | High | High |
| Phosphate | Poor | Poor |
| Temperature | Good | High |
| pH | High | High |
| Hydromorphological Supporting Elements | Supports good | Supports good |
| Hydrological Regime | Does not support good | Does not support good |
| Supporting elements (Surface Water) | Moderate | Moderate |
| Mitigation Measures Assessment | Moderate or less | Moderate or less |
| Specific pollutants | High | High |
| Arsenic | High | High |
| Copper | High | High |
| Iron | High | High |
| Manganese | High | High |
| Permethrin | High | High |
| Triclosan | High | High |
| Zinc | High | High |
| Chemical | Fail | Does not require assessment |
| Priority hazardous substances | Fail | Does not require assessment |
| Benzo(a)pyrene | Good | |
| Cadmium and Its Compounds | Good | |
| Dioxins and dioxin-like compounds | Good | |
| Heptachlor and cis-Heptachlor epoxide | Good | |
| Hexabromocyclododecane (HBCDD) | Good | |
| Hexachlorobenzene | Good | |
| Hexachlorobutadiene | Good | |
| Hexachlorocyclohexane | Good | |
| Mercury and Its Compounds | Good | |
| Nonylphenol | Good | |
| Perfluorooctane sulphonate (PFOS) | Fail | |
| Polybrominated diphenyl ethers (PBDE) | Fail | |
| Tributyltin Compounds | Good | |
| Trifluralin (Priority hazardous) | Good | |
| Priority substances | Good | Does not require assessment |
| 1,2-dichloroethane | Good | |
| Atrazine | Good | |
| Cypermethrin (Priority) | Good | |
| Fluoranthene | Good | |
| Lead and Its Compounds | Good | |
| Nickel and Its Compounds | Good | |
| Pentachlorophenol | Good | |
| Simazine | Good | |
| Trichlorobenzenes | Good | |
| Trichloromethane | Good | |
| Other Pollutants | Good | Does not require assessment |
| Aldrin, Dieldrin, Endrin & Isodrin | Good | |
| Carbon Tetrachloride | Good | |
| DDT Total | Good | |
| Tetrachloroethylene | Good | |
| Trichloroethylene | Good | |
| para - para DDT | Good |
Investigations into classification status
No data to show
Reasons for not achieving good (RNAG) and reasons for deterioration (RFD)
All reasons (RFDs and RNAGs) attributed to the classification elements in this water body.
| Reason Type | SWMI | Activity | Category | Classification Element | More information |
|---|---|---|---|---|---|
| RNAG | Physical modification | Urbanisation - urban development | Urban and transport | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Point source | Misconnections | Domestic General Public | Phosphate | Details |
| RNAG | Flow | Groundwater abstraction | Water Industry | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Point source | Private Sewage Treatment | Urban and transport | Phosphate | Details |
| RFD | Natural | Drought | No sector responsible | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Point source | Sewage discharge (intermittent) | Water Industry | Phosphate | Details |
| RNAG | Unknown (pending investigation) | Unknown (pending investigation) | Sector under investigation | Perfluorooctane sulphonate (PFOS) | Details |
| RNAG | measures delivered to address reason, awaiting recovery | Not applicable | No sector responsible | Polybrominated diphenyl ethers (PBDE) | Details |
| RNAG | Point source | Sewage discharge (continuous) | Water Industry | Phosphate | Details |
| RNAG | Diffuse source | Urbanisation - urban development | Urban and transport | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Physical modification | Urbanisation - urban development | Urban and transport | Hydrological Regime | Details |
| RNAG | Point source | Misconnections | Domestic General Public | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Flow | Groundwater abstraction | Water Industry | Hydrological Regime | Details |
| RNAG | Point source | Private Sewage Treatment | Urban and transport | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Physical modification | Other (not in list, must add details in comments) | Local and Central Government | Mitigation Measures Assessment | Details |
| RNAG | Point source | Sewage discharge (intermittent) | Water Industry | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Physical modification | Other (not in list, must add details in comments) | Recreation | Mitigation Measures Assessment | Details |
| RNAG | Point source | Sewage discharge (continuous) | Water Industry | Macrophytes and Phytobenthos Combined | Details |
| RNAG | Diffuse source | Urbanisation - urban development | Urban and transport | Phosphate | Details |
Reasons for not achieving good status by business sector
The issues preventing waters reaching good status and the sectors identified as contributing to them. The numbers in the table are individual counts of the reasons for not achieving good status with a confidence status of 'confirmed' and 'probable', where the latest classification is less than good status. There may be more than one reason in a single water body. Note, table does not include reasons for deterioration.
| Significant water management issue | Physical modifications | Pollution from waste water | Pollution from towns, cities and transport | Changes to the natural flow and level of water | Invasive non-native species | Pollution from rural areas | Pollution from abandoned mines |
|---|---|---|---|---|---|---|---|
| Agriculture and rural land management | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Industry | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Mining and quarrying | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Navigation | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Urban and transport | 1 | 0 | 1 | 0 | 0 | 0 | 0 |
| Water Industry | 0 | 2 | 0 | 1 | 0 | 0 | 0 |
| Local & central government | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Domestic general public | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Recreation | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Waste treatment and disposal | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Other | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| No sector responsible | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Sector under investigation | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Total | 3 | 2 | 1 | 1 | 0 | 0 | 0 |
Objectives
| Classification Item | Status | Year | Reasons |
|---|---|---|---|
| Ecological | Moderate | 2015 | Disproportionately expensive: Disproportionate burdens; Technically infeasible: No known technical solution is available |
| Biological quality elements | Good | 2021 | Disproportionately expensive: Disproportionate burdens |
| Fish | Good | 2021 | Disproportionately expensive: Disproportionate burdens |
| Invertebrates | Good | 2015 | |
| Macrophytes and Phytobenthos Combined | Good | 2015 | |
| Physico-chemical quality elements | Moderate | 2015 | Technically infeasible: No known technical solution is available |
| Acid Neutralising Capacity | Good | 2015 | |
| Ammonia (Phys-Chem) | Good | 2015 | |
| Dissolved oxygen | Good | 2015 | |
| Phosphate | Moderate | 2027 | Technically infeasible: No known technical solution is available |
| Temperature | Good | 2015 | |
| pH | Good | 2015 | |
| Hydromorphological Supporting Elements | Supports good | 2015 | |
| Hydrological Regime | Does not support good | 2015 | Disproportionately expensive: Unfavourable balance of costs and benefits |
| Supporting elements (Surface Water) | Good | 2027 - Low confidence | Disproportionately expensive: Disproportionate burdens |
| Mitigation Measures Assessment | Good | 2027 - Low confidence | Disproportionately expensive: Disproportionate burdens |
| Specific pollutants | High | 2015 | |
| Arsenic | High | 2015 | |
| Copper | High | 2015 | |
| Iron | High | 2015 | |
| Manganese | High | 2015 | |
| Permethrin | High | 2015 | |
| Triclosan | High | 2015 | |
| Zinc | High | 2015 | |
| Chemical | Good | 2063 | Natural conditions: Chemical status recovery time; Technically infeasible: No known technical solution is available |
| Priority hazardous substances | Good | 2063 | Natural conditions: Chemical status recovery time; Technically infeasible: No known technical solution is available |
| Benzo (b) and (k) fluoranthene | Good | 2015 | |
| Benzo (ghi) perelyene and indeno (123-cd) pyrene | Good | 2015 | |
| Benzo(a)pyrene | Good | 2015 | |
| Cadmium and Its Compounds | Good | 2015 | |
| Dioxins and dioxin-like compounds | Good | 2015 | |
| Heptachlor and cis-Heptachlor epoxide | Good | 2015 | |
| Hexabromocyclododecane (HBCDD) | Good | 2015 | |
| Hexachlorobenzene | Good | 2015 | |
| Hexachlorobutadiene | Good | 2015 | |
| Hexachlorocyclohexane | Good | 2015 | |
| Mercury and Its Compounds | Good | 2015 | |
| Nonylphenol | Good | 2015 | |
| Perfluorooctane sulphonate (PFOS) | Good | 2039 | Technically infeasible: No known technical solution is available |
| Polybrominated diphenyl ethers (PBDE) | Good | 2063 | Natural conditions: Chemical status recovery time |
| Tributyltin Compounds | Good | 2015 | |
| Trifluralin (Priority hazardous) | Good | 2015 | |
| Priority substances | Good | 2015 | |
| 1,2-dichloroethane | Good | 2015 | |
| Atrazine | Good | 2015 | |
| Cypermethrin (Priority) | Good | 2015 | |
| Fluoranthene | Good | 2015 | |
| Lead and Its Compounds | Good | 2015 | |
| Nickel and Its Compounds | Good | 2015 | |
| Pentachlorophenol | Good | 2015 | |
| Simazine | Good | 2015 | |
| Trichlorobenzenes | Good | 2015 | |
| Trichloromethane | Good | 2015 | |
| Other Pollutants | Good | 2015 | |
| Aldrin, Dieldrin, Endrin & Isodrin | Good | 2015 | |
| Carbon Tetrachloride | Good | 2015 | |
| DDT Total | Good | 2015 | |
| Tetrachloroethylene | Good | 2015 | |
| Trichloroethylene | Good | 2015 | |
| para - para DDT | Good | 2015 |
Protected areas
| PA Name | Id | Directive | More information |
|---|---|---|---|
| Lower Thames (Cookham Egham Teddington) | SWSGZ4016 | Safeguard Zone | |
| South West London Waterbodies | UK9012171 | Special Protection Area | Natural England |
| South West London Waterbodies | UK11065 | Ramsar Site | Natural England |
Monitoring sites which have been used to classify this water body
Shows which sites were used for classification for which years within each cycle.