Hogsmill Water Body
Moderate ecological status
Get Hogsmill data
Attributes
- Water Body IDGB106039017440
- Water Body TypeRiver
- Hydromorphological designationheavily modified
- NGRTQ2086666242
- Catchment area7263.62 ha
- Length9.908 km
- Catchment area72.636 km2
- Surveillance Water BodyNo
Classifications
| Classification Item | 2019 | 2022 |
|---|---|---|
| Ecological | Moderate | Moderate |
| Biological quality elements | Poor | Poor |
| Fish | Poor | Moderate |
| Invertebrates | Poor | Poor |
| Macrophytes and Phytobenthos Combined | ||
| Macrophytes Sub Element | Poor | Poor |
| Physico-chemical quality elements | Moderate | Moderate |
| Ammonia (Phys-Chem) | Good | High |
| Dissolved oxygen | Good | High |
| Phosphate | Poor | Poor |
| Temperature | High | High |
| pH | High | High |
| Hydromorphological Supporting Elements | Supports good | Supports good |
| Hydrological Regime | Supports good | Supports good |
| Supporting elements (Surface Water) | Moderate | Moderate |
| Mitigation Measures Assessment | Moderate or less | Moderate or less |
| Specific pollutants | High | High |
| Chlorothalonil | High | High |
| Copper | High | High |
| Diazinon | High | High |
| Dimethoate | High | High |
| Iron | High | High |
| Pendimethalin | 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 | |
| Benzo(b)fluoranthene | Good | |
| Benzo(g-h-i)perylene | Good | |
| Benzo(k)fluoranthene | Good | |
| Cadmium and Its Compounds | Good | |
| Di(2-ethylhexyl)phthalate (Priority hazardous) | 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 | |
| Pentachlorobenzene | Good | |
| Perfluorooctane sulphonate (PFOS) | Fail | |
| Polybrominated diphenyl ethers (PBDE) | Fail | |
| Quinoxyfen | Good | |
| Priority substances | Fail | Does not require assessment |
| Aclonifen | Good | |
| Alachlor | Good | |
| Bifenox | Good | |
| Cybutryne | Good | |
| Cypermethrin (Priority) | Fail | |
| Dichlorvos (Priority) | Good | |
| Fluoranthene | Good | |
| Lead and Its Compounds | Good | |
| Nickel and Its Compounds | Good | |
| Terbutryn | Good | |
| Other Pollutants | Does not require assessment | Does not require assessment |
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 | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RNAG | Point source | Misconnections | Domestic General Public | Invertebrates | Details |
| RNAG | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RFD | High to Good deterioration, no action required (RFD only) | Not applicable | No sector responsible | Ammonia (Phys-Chem) | Details |
| RNAG | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RNAG | Unknown (pending investigation) | Unknown (pending investigation) | Sector under investigation | Cypermethrin (Priority) | Details |
| RNAG | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RNAG | Physical modification | Other (not in list, must add details in comments) | Local and Central Government | Mitigation Measures Assessment | Details |
| RNAG | Physical modification | Urbanisation - transport | Urban and transport | Invertebrates | Details |
| RFD | Other pressures | Fish stocking | Other | Fish | Details |
| RNAG | Unknown (pending investigation) | Unknown (pending investigation) | Sector under investigation | Perfluorooctane sulphonate (PFOS) | Details |
| RNAG | Point source | Leaking utility sewers | Water Industry | Invertebrates | Details |
| RFD | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RNAG | measures delivered to address reason, awaiting recovery | Not applicable | No sector responsible | Polybrominated diphenyl ethers (PBDE) | Details |
| RNAG | Physical modification | Urbanisation - urban development | Urban and transport | Invertebrates | Details |
| RFD | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RNAG | Point source | Misconnections | Domestic General Public | Phosphate | Details |
| RNAG | Physical modification | Flood protection - structures | Urban and transport | Invertebrates | Details |
| RNAG | Point source | Sewage discharge (continuous) | Water Industry | Phosphate | Details |
| RNAG | Point source | Sewage discharge (continuous) | Water Industry | Invertebrates | Details |
| RFD | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RNAG | Point source | Sewage discharge (intermittent) | Water Industry | Phosphate | Details |
| RNAG | Point source | Sewage discharge (intermittent) | Water Industry | Invertebrates | Details |
| RFD | Point source | Sewage discharge (intermittent) | Water Industry | Fish | Details |
| RFD | High to Good deterioration, no action required (RFD only) | Not applicable | No sector responsible | Dissolved oxygen | 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 | 3 | 0 | 0 | 0 | 0 | 0 | 0 |
| Water Industry | 0 | 4 | 1 | 0 | 0 | 0 | 0 |
| Local & central government | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Domestic general public | 0 | 0 | 2 | 0 | 0 | 0 | 0 |
| Recreation | 0 | 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 | 4 | 4 | 3 | 0 | 0 | 0 | 0 |
Objectives
| Classification Item | Status | Year | Reasons |
|---|---|---|---|
| Ecological | Moderate | 2015 | Disproportionately expensive: Disproportionate burdens; Good status prevented by A/HMWB designated use: Action to get biological element to good would have significant adverse impact on use; Technically infeasible: No known technical solution is available |
| Biological quality elements | Poor | 2021 | Disproportionately expensive: Disproportionate burdens; Good status prevented by A/HMWB designated use: Action to get biological element to good would have significant adverse impact on use |
| Fish | Poor | 2021 | Disproportionately expensive: Disproportionate burdens; Good status prevented by A/HMWB designated use: Action to get biological element to good would have significant adverse impact on use |
| Invertebrates | Good | 2027 - Low confidence | Disproportionately expensive: Disproportionate burdens |
| Macrophytes and Phytobenthos Combined | Not assessed | 2015 | Disproportionately expensive: Disproportionate burdens |
| Physico-chemical quality elements | Moderate | 2015 | Technically infeasible: No known technical solution is available |
| Ammonia (Phys-Chem) | Good | 2015 | |
| Dissolved oxygen | Good | 2015 | |
| Phosphate | Poor | 2015 | Technically infeasible: No known technical solution is available |
| Temperature | Good | 2015 | |
| pH | Good | 2015 | |
| Hydromorphological Supporting Elements | Supports good | 2015 | |
| Hydrological Regime | Supports good | 2015 | |
| 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 | |
| Chlorothalonil | High | 2015 | |
| Copper | High | 2015 | |
| Diazinon | High | 2015 | |
| Dimethoate | High | 2015 | |
| Iron | High | 2015 | |
| Pendimethalin | High | 2015 | |
| Permethrin | High | 2015 | |
| Triclosan | High | 2015 | |
| Zinc | High | 2015 | |
| Chemical | Good | 2063 | Disproportionately expensive: Disproportionate burdens; 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 | |
| Benzo(b)fluoranthene | Good | 2015 | |
| Benzo(g-h-i)perylene | Good | 2015 | |
| Benzo(k)fluoranthene | Good | 2015 | |
| Cadmium and Its Compounds | Good | 2015 | |
| Di(2-ethylhexyl)phthalate (Priority hazardous) | 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 | |
| Pentachlorobenzene | 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 |
| Quinoxyfen | Good | 2015 | |
| Priority substances | Good | 2039 | Disproportionately expensive: Disproportionate burdens |
| Aclonifen | Good | 2015 | |
| Alachlor | Good | 2015 | |
| Bifenox | Good | 2015 | |
| Cybutryne | Good | 2015 | |
| Cypermethrin (Priority) | Good | 2039 | Disproportionately expensive: Disproportionate burdens |
| Dichlorvos (Priority) | Good | 2015 | |
| Fluoranthene | Good | 2015 | |
| Lead and Its Compounds | Good | 2015 | |
| Nickel and Its Compounds | Good | 2015 | |
| Terbutryn | Good | 2015 | |
| Other Pollutants | Does not require assessment | 2015 |
Protected areas
| PA Name | Id | Directive | More information |
|---|---|---|---|
| Mole Gap To Reigate Escarpment | UK0012804 | Special Area of Conservation | Natural England |
| Hogsmill NVZ | S450 | Nitrates Directive |
Monitoring sites which have been used to classify this water body
Shows which sites were used for classification for which years within each cycle.