Silk Stream and Edgware Brook Water Body

Moderate ecological status

Attributes

  • Water Body IDGB106039022970
  • Water Body TypeRiver
  • Hydromorphological designationheavily modified
  • NGRTQ1761891156
  • Catchment area33.737 km2
  • Surveillance Water BodyNo
  • Catchment area3373.74 ha
  • Length16.258 km

Classifications

Classification Item2019
EcologicalModerate
Biological quality elementsPoor
FishModerate
InvertebratesPoor
Macrophytes and Phytobenthos Combined
Macrophytes Sub ElementPoor
Physico-chemical quality elementsModerate
Ammonia (Phys-Chem)Good
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
RNAGPoint sourceIncidentsSector under investigationDissolved oxygenDetails
RNAGPoint sourceSewage discharge (intermittent)Water IndustryDissolved oxygenDetails
RNAGDiffuse sourceUrbanisation - urban developmentUrban and transportDissolved oxygenDetails
RNAGPoint sourceSewage discharge (intermittent)Water IndustryAmmonia (Phys-Chem)Details
RNAGPoint sourceMisconnectionsDomestic General PublicAmmonia (Phys-Chem)Details
RNAGUnknown (pending investigation)Unknown (pending investigation)Sector under investigationBenzo(g-h-i)peryleneDetails
RNAGPhysical modificationOther (not in list, must add details in comments)Urban and transportMitigation Measures AssessmentDetails
RNAGPoint sourceSewage discharge (intermittent)Water IndustryPhosphateDetails
RNAGmeasures delivered to address reason, awaiting recoveryNot applicableNo sector responsiblePolybrominated diphenyl ethers (PBDE)Details
RNAGPoint sourceMisconnectionsDomestic General PublicPhosphateDetails
RNAGPhysical modificationUrbanisation - urban developmentUrban and transportInvertebratesDetails
RNAGPhysical modificationUrbanisation - urban developmentUrban and transportFishDetails
RNAGDiffuse sourceUrbanisation - urban developmentUrban and transportPhosphateDetails

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 Industry0200000
Local & central government0000000
Domestic general public0010000
Recreation0000000
Waste treatment and disposal0000000
Other0000000
No sector responsible0000000
Sector under investigation0000000
Total3220000

Objectives

Classification ItemStatusYearReasons
EcologicalGood2027 - Low confidenceDisproportionately 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
Biological quality elementsModerate2027 - Low confidenceDisproportionately 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
FishModerate2015Good status prevented by A/HMWB designated use: Action to get biological element to good would have significant adverse impact on use
InvertebratesModerate2027 - Low confidenceDisproportionately 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
Macrophytes and Phytobenthos CombinedNot assessed2015Disproportionately 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
Physico-chemical quality elementsGood2027 - Low confidenceDisproportionately expensive: Disproportionate burdens
Ammonia (Phys-Chem)Good2021Disproportionately 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
BRENT/SILK STREAM/EDGEWARE ROAD/ 163922009, 2011
SILK STREAM AT SILK BRIDGE, A5, HENDON PBRR00942014, 20092016, 2014, 2015, 20192019
34226 3422620142015, 2016, 2014, 20192019
160631 16063120142019, 2015, 2014, 20162019
BRENT/SILK STREAM/RUSHGROVE PARK/ 4724620142015, 2016, 2019, 20142019
BRENT/SILK STREAM/SILK STREAM PARK/ 323342013, 2014, 20122015, 2013, 2016, 2014

Upstream water bodies

    Downstream water bodies