Dollis Brook and Upper Brent Water Body

Moderate ecological status

Attributes

  • Water Body IDGB106039022980
  • Water Body TypeRiver
  • Hydromorphological designationheavily modified
  • NGRTQ2555092799
  • Catchment area4308.27 ha
  • Length16.986 km
  • Catchment area43.083 km2
  • Surveillance Water BodyNo

Classifications

Classification Item2019
EcologicalModerate
Biological quality elementsPoor
InvertebratesPoor
Macrophytes and Phytobenthos Combined
Macrophytes Sub ElementPoor
Physico-chemical quality elementsModerate
Ammonia (Phys-Chem)Moderate
Dissolved oxygenBad
PhosphatePoor
TemperatureHigh
pHHigh
Hydromorphological Supporting ElementsSupports good
Hydrological RegimeSupports good
Supporting elements (Surface Water)Moderate
Mitigation Measures AssessmentModerate or less
Specific pollutantsHigh
TriclosanHigh
ChemicalFail
Priority hazardous substancesFail
Benzo(a)pyreneGood
Benzo(b)fluorantheneGood
Benzo(g-h-i)peryleneFail
Benzo(k)fluorantheneGood
Dioxins and dioxin-like compoundsGood
Heptachlor and cis-Heptachlor epoxideGood
Hexabromocyclododecane (HBCDD)Good
HexachlorobenzeneGood
HexachlorobutadieneGood
Mercury and Its CompoundsGood
NonylphenolGood
Perfluorooctane sulphonate (PFOS)Good
Polybrominated diphenyl ethers (PBDE)Fail
Priority substancesGood
Cypermethrin (Priority)Good
FluorantheneGood
Other PollutantsDoes 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
RNAGUnknown (pending investigation)Unknown (pending investigation)Sector under investigationBenzo(g-h-i)peryleneDetails
RNAGmeasures delivered to address reason, awaiting recoveryNot applicableNo sector responsiblePolybrominated diphenyl ethers (PBDE)Details
RNAGDiffuse sourceUrbanisation - urban developmentUrban and transportInvertebratesDetails
RNAGPoint sourceIncidentsOtherInvertebratesDetails
RNAGPoint sourceSewage discharge (intermittent)Water IndustryInvertebratesDetails
RNAGDiffuse sourceUrbanisation - urban developmentUrban and transportInvertebratesDetails
RNAGPoint sourceSewage discharge (intermittent)Water IndustryDissolved oxygenDetails
RNAGPoint sourceMisconnectionsDomestic General PublicInvertebratesDetails
RNAGDiffuse sourceUrbanisation - urban developmentUrban and transportAmmonia (Phys-Chem)Details
RNAGPoint sourceMisconnectionsDomestic General PublicAmmonia (Phys-Chem)Details
RNAGPoint sourceSewage discharge (intermittent)Water IndustryInvertebratesDetails
RNAGPhysical modificationOther (not in list, must add details in comments)Urban and transportMitigation Measures AssessmentDetails
RNAGPoint sourceSewage discharge (intermittent)Water IndustryAmmonia (Phys-Chem)Details
RNAGPhysical modificationFlood protection - structuresUrban and transportInvertebratesDetails
RNAGPhysical modificationUrbanisation - urban developmentUrban and transportInvertebratesDetails
RNAGPhysical modificationOther (not in list, must add details in comments)Local and Central GovernmentMitigation Measures AssessmentDetails
RNAGDiffuse sourceUrbanisation - urban developmentUrban and transportPhosphateDetails
RNAGPoint sourceMisconnectionsDomestic General PublicPhosphateDetails
RNAGPoint sourceSewage discharge (intermittent)Water IndustryPhosphateDetails
RNAGDiffuse sourceUrbanisation - urban developmentUrban and transportDissolved oxygenDetails
RNAGPoint sourceIncidentsOtherDissolved oxygenDetails

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
Industry0000000
Mining and quarrying0000000
Navigation0000000
Urban and transport3010000
Water Industry0500000
Local & central government1000000
Domestic general public0030000
Recreation0000000
Waste treatment and disposal0000000
Other0000000
No sector responsible0000000
Sector under investigation0000000
Total4540000

Objectives

Classification ItemStatusYearReasons
EcologicalGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Biological quality elementsGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
InvertebratesGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Macrophytes and Phytobenthos CombinedNot assessed2015Disproportionately expensive: Disproportionate burdens
Physico-chemical quality elementsGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Ammonia (Phys-Chem)Good2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Dissolved oxygenGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
PhosphateGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
TemperatureGood2015
pHGood2015
Hydromorphological Supporting ElementsSupports good2015
Hydrological RegimeSupports good2015
Supporting elements (Surface Water)Good2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Mitigation Measures AssessmentGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Specific pollutantsHigh2015
TriclosanHigh2015
ChemicalGood2063Natural conditions: Chemical status recovery time;
Technically infeasible: No known technical solution is available
Priority hazardous substancesGood2063Natural conditions: Chemical status recovery time;
Technically infeasible: No known technical solution is available
Benzo(a)pyreneGood2015
Benzo(b)fluorantheneGood2015
Benzo(g-h-i)peryleneGood2033Technically infeasible: No known technical solution is available
Benzo(k)fluorantheneGood2015
Dioxins and dioxin-like compoundsGood2015
Heptachlor and cis-Heptachlor epoxideGood2015
Hexabromocyclododecane (HBCDD)Good2015
HexachlorobenzeneGood2015
HexachlorobutadieneGood2015
Mercury and Its CompoundsGood2015
NonylphenolGood2015
Perfluorooctane sulphonate (PFOS)Good2015
Polybrominated diphenyl ethers (PBDE)Good2063Natural conditions: Chemical status recovery time
Priority substancesGood2015
Cypermethrin (Priority)Good2015
FluorantheneGood2015
Other PollutantsDoes not require assessment2015

Protected areas

No data to show

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
DOLLIS BROOK ABOVE MUTTON BROOK, HENDON PBRR00602016, 2015, 20192019
BRENT AT PRIESTLEY WAY, HENDON PBRR00702014, 20092016, 2014, 2015, 20192019
34224 342242013, 2011, 2012, 20142014, 2019, 2016, 20152019

Upstream water bodies

    Downstream water bodies