Purwell Water Body Moderate ecological status
Attributes Water Body ID GB105033037690 Water Body Type River Hydromorphological designation heavily modified NGR TL1970130253 Catchment area 51.734 km2 Surveillance Water Body No Length 5.766 km Catchment area 5173.35 ha Classifications Classification Item 2019 2022 Ecological Moderate Moderate Biological quality elements Poor Poor Fish Poor Poor Invertebrates Good Good Macrophytes and Phytobenthos Combined Macrophytes Sub Element Moderate Moderate Physico-chemical quality elements High High Ammonia (Phys-Chem) High High Biochemical Oxygen Demand (BOD) High Dissolved oxygen High High Phosphate High High 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 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
Why do all water bodies have a chemical status of fail?
Investigations into classification status Classification Element Cycle Year Status Outcome Phosphate 2 2013 Poor Certain there is not a problem
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 Flood protection - sediment management Local and Central Government Fish Details RNAG Physical modification Flood protection - water level management Local and Central Government Fish Details RNAG Physical modification Barriers - ecological discontinuity Urban and transport Fish Details RNAG Physical modification Other (not in list, must add details in comments) Urban and transport Mitigation Measures Assessment Details RNAG Flow No further action (Flow is below the EFI but NOT causing an ecological failure) No sector responsible Hydrological Regime 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 (continuous) Water Industry 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 2 0 0 0 0 0 0 Water Industry 0 0 0 0 0 0 0 Local & central government 3 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 0 0 0 Sector under investigation 0 0 0 0 0 0 0 Total 5 0 0 0 0 0 0
Objectives Classification Item Status Year Reasons Ecological Good 2027 - Low confidence Disproportionately expensive: Disproportionate burdens Biological quality elements Good 2027 - Low confidence Disproportionately expensive: Disproportionate burdens Fish Good 2027 - Low confidence Disproportionately expensive: Disproportionate burdens Invertebrates Good 2021 Disproportionately expensive: Disproportionate burdens Macrophytes and Phytobenthos Combined Not assessed 2015 Disproportionately expensive: Disproportionate burdens Physico-chemical quality elements Good 2021 Disproportionately expensive: Disproportionate burdens Ammonia (Phys-Chem) Good 2015 Dissolved oxygen Good 2015 Phosphate Good 2021 Disproportionately expensive: Disproportionate burdens 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 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.
Monitoring Site Cycle 1 Cycle 2 Cycle 3 R.PURWELL A505 RD.BR. HITCHIN 13M24 2012, 2013, 2014 2015, 2013, 2019, 2016, 2014 2022, 2019 MIDDLE OUSE/PURWELL/PURWELL COMMON/ 4755 2014, 2012, 2010, 2013, 2011 2014, 2013, 2019 2022, 2019 56219 56219 2014, 2013, 2011 2015, 2016, 2014, 2013 MIDDLE OUSE/PURWELL/D/S WALSWORTH COMMON/ 55245 2015, 2016 R.HIZ CADWELL ARCH 13M04 2009 R.HIZ U/S HITCHIN STW 13M03 2009 MIDDLE OUSE/PURWELL/WALSWORTH COMMON/ 55244 2019 2022, 2019