Hiz (through Hitchin) Water Body
Moderate ecological status
Get Hiz (through Hitchin) data
Attributes
- Water Body IDGB105033037680
- Water Body TypeRiver
- Hydromorphological designationheavily modified
- NGRTL1850128911
- Catchment area1800.17 ha
- Length3.674 km
- Catchment area18.002 km2
- Surveillance Water BodyNo
Classifications
| Classification Item | 2019 | 2022 |
|---|---|---|
| Ecological | Moderate | Moderate |
| Biological quality elements | Bad | Bad |
| Fish | Bad | Bad |
| Invertebrates | Poor | Poor |
| Macrophytes and Phytobenthos Combined | High | High |
| Phytobenthos Sub Element | High | High |
| Physico-chemical quality elements | High | Moderate |
| Ammonia (Phys-Chem) | High | Good |
| Biochemical Oxygen Demand (BOD) | Moderate | |
| Dissolved oxygen | High | Good |
| Phosphate | High | Moderate |
| Temperature | High | High |
| pH | High | High |
| Supporting elements (Surface Water) | Moderate | Moderate |
| Mitigation Measures Assessment | Moderate or less | Moderate or less |
| Chemical | Fail | Does not require assessment |
| Priority hazardous substances | Fail | Does not require assessment |
| Benzo(a)pyrene | Good | |
| Dioxins and dioxin-like compounds | Good | |
| Heptachlor and cis-Heptachlor epoxide | Good | |
| Hexabromocyclododecane (HBCDD) | Good | |
| Hexachlorobenzene | Good | |
| Hexachlorobutadiene | Good | |
| Mercury and Its Compounds | Good | |
| Perfluorooctane sulphonate (PFOS) | Good | |
| Polybrominated diphenyl ethers (PBDE) | Fail | |
| Priority substances | Good | Does not require assessment |
| Cypermethrin (Priority) | Good | |
| Fluoranthene | 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 | measures delivered to address reason, awaiting recovery | Not applicable | No sector responsible | Polybrominated diphenyl ethers (PBDE) | Details |
| RNAG | Physical modification | Other (not in list, must add details in comments) | Urban and transport | Mitigation Measures Assessment | Details |
| RNAG | Diffuse source | Transport Drainage | Urban and transport | Invertebrates | Details |
| RNAG | Invasive non-native species | North american signal crayfish | No sector responsible | Invertebrates | Details |
| RNAG | Physical modification | Barriers - ecological discontinuity | Urban and transport | Fish | Details |
| RNAG | Physical modification | Urbanisation - urban development | Urban and transport | Fish | 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 | 0 | 0 | 0 | 0 | 0 | 0 |
| Local & central government | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Domestic general public | 0 | 0 | 0 | 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 | 1 | 0 | 0 |
| Sector under investigation | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Total | 3 | 0 | 0 | 0 | 1 | 0 | 0 |
Objectives
| Classification Item | Status | Year | Reasons |
|---|---|---|---|
| Ecological | Good | 2027 - Low confidence | 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 | 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 |
| Fish | Poor | 2015 | Good status prevented by A/HMWB designated use: Action to get biological element to good would have significant adverse impact on use |
| Invertebrates | Poor | 2021 | Technically infeasible: No known technical solution is available |
| Macrophytes and Phytobenthos Combined | Good | 2015 | |
| Physico-chemical quality elements | Good | 2015 | |
| Ammonia (Phys-Chem) | Good | 2015 | |
| Dissolved oxygen | Good | 2015 | |
| Phosphate | Good | 2015 | |
| Temperature | Good | 2015 | |
| pH | Good | 2015 | |
| Hydromorphological Supporting Elements | Not assessed | 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 | Not assessed | 2015 | |
| Chemical | Good | 2063 | Natural conditions: Chemical status recovery time |
| Priority hazardous substances | Good | 2063 | Natural conditions: Chemical status recovery time |
| Benzo(a)pyrene | 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 | |
| Mercury and Its Compounds | Good | 2015 | |
| Perfluorooctane sulphonate (PFOS) | Good | 2015 | |
| Polybrominated diphenyl ethers (PBDE) | Good | 2063 | Natural conditions: Chemical status recovery time |
| Priority substances | Good | 2015 | |
| Cypermethrin (Priority) | Good | 2015 | |
| Fluoranthene | Good | 2015 | |
| Other Pollutants | Does not require assessment | 2015 |
Protected areas
| PA Name | Id | Directive | More information |
|---|---|---|---|
| Great Ouse NVZ | S391 | Nitrates Directive | |
| Anglian Chalk | G71 | 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.