Darwell Reservoir Water Body

Good ecological status


  • Water Body IDGB30744955
  • Water Body TypeLake
  • Hydromorphological designationheavily modified
  • NGRTQ7124921045
  • Mean depth6.757 m
  • Altitude43 m
  • Surveillance Water BodyNo
  • Surface area0.582 km2
  • Surface area58.172 ha
  • Catchment area954.25 ha


Classification Item20192022
Biological quality elementsGood
Physico-chemical quality elementsGood
Total PhosphorusGood
Supporting elements (Surface Water)Moderate
Expert JudgementModerate
Mitigation Measures AssessmentGood
Specific pollutantsHigh
ChemicalFailDoes not require assessment
Priority hazardous substancesFailDoes not require assessment
Dioxins and dioxin-like compoundsGood
Heptachlor and cis-Heptachlor epoxideGood
Hexabromocyclododecane (HBCDD)Good
Mercury and Its CompoundsFail
Perfluorooctane sulphonate (PFOS)Good
Polybrominated diphenyl ethers (PBDE)Fail
Priority substancesGoodDoes not require assessment
Other PollutantsDoes not require assessmentDoes not require assessment

Why do all water bodies have a chemical status of fail?

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 TypeSWMIActivityCategoryClassification ElementMore information
RFDHigh to Good deterioration, no action required (RFD only)Not applicableNo sector responsiblePhytoplanktonDetails
RNAGmeasures delivered to address reason, awaiting recoveryNot applicableNo sector responsibleMercury and Its CompoundsDetails
RNAGmeasures delivered to address reason, awaiting recoveryNot applicableNo sector responsiblePolybrominated diphenyl ethers (PBDE)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 issuePhysical modificationsPollution from waste waterPollution from towns, cities and transportChanges to the natural flow and level of waterInvasive non-native speciesPollution from rural areasPollution from abandoned mines
Agriculture and rural land management0000000
Mining and quarrying0000000
Urban and transport0000000
Water Industry0000000
Local & central government0000000
Domestic general public0000000
Waste treatment and disposal0000000
No sector responsible0000000
Sector under investigation0000000


Classification ItemStatusYearReasons
EcologicalGood2021Disproportionately expensive: Disproportionate burdens
Biological quality elementsGood2015
Physico-chemical quality elementsGood2021Disproportionately expensive: Disproportionate burdens
Total PhosphorusGood2021Disproportionately expensive: Disproportionate burdens
Hydromorphological Supporting ElementsNot assessed2015
Supporting elements (Surface Water)Good2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Expert JudgementGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Mitigation Measures AssessmentGood2015
Specific pollutantsHigh2015
ChemicalGood2063Natural conditions: Chemical status recovery time
Priority hazardous substancesGood2063Natural conditions: Chemical status recovery time
Dioxins and dioxin-like compoundsGood2015
Heptachlor and cis-Heptachlor epoxideGood2015
Hexabromocyclododecane (HBCDD)Good2015
Mercury and Its CompoundsGood2040Natural conditions: Chemical status recovery time
Perfluorooctane sulphonate (PFOS)Good2015
Polybrominated diphenyl ethers (PBDE)Good2063Natural conditions: Chemical status recovery time
Priority substancesGood2015
Other PollutantsDoes not require assessment2015

Protected areas

PA NameIdDirectiveMore information
Lower Rother from Robertsbridge to Scots Float and Darwell ReservoirSWSGZ4221Safeguard Zone
Darwell ReservoirUKENLK127Urban Waste Water Treatment Directive
Darwell ReservoirUKGB30744955Drinking Water Protected Area

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 SiteCycle 1Cycle 2Cycle 3
DARWELL RES AT DRAW OFF TOWER E00173542009, 20122015, 2016

Upstream water bodies

    Downstream water bodies