Swan (Swanage) Water Body

Poor ecological status


  • Water Body IDGB108044009920
  • Water Body TypeRiver
  • Hydromorphological designationnot designated artificial or heavily modified
  • NGRSZ0136179354
  • Length4.75 km
  • Surveillance Water BodyNo
  • Catchment area15.092 km2
  • Catchment area1509.222 ha


Classification Item20192022
Biological quality elementsPoorPoor
Macrophytes and Phytobenthos CombinedPoorPoor
Macrophytes Sub ElementModerateModerate
Phytobenthos Sub ElementPoorPoor
Physico-chemical quality elementsGoodGood
Ammonia (Phys-Chem)HighHigh
Dissolved oxygenGoodGood
Hydromorphological Supporting ElementsSupports goodSupports good
Hydrological RegimeHighHigh
MorphologySupports goodSupports good
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
Cypermethrin (Priority)Good
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
RNAGmeasures delivered to address reason, awaiting recoveryNot applicableNo sector responsibleMercury and Its CompoundsDetails
RNAGSuspect dataNot applicableNo sector responsibleMacrophytes and Phytobenthos CombinedDetails
RNAGPhysical modificationFlood protection - structuresLocal and Central GovernmentMacrophytes and Phytobenthos CombinedDetails
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 government1000000
Domestic general public0000000
Waste treatment and disposal0000000
No sector responsible0000000
Sector under investigation0000000


Classification ItemStatusYearReasons
EcologicalPoor2015Disproportionately expensive: Unfavourable balance of costs and benefits
Biological quality elementsPoor2015Disproportionately expensive: Unfavourable balance of costs and benefits
Macrophytes and Phytobenthos CombinedPoor2015Disproportionately expensive: Unfavourable balance of costs and benefits
Physico-chemical quality elementsGood2015
Ammonia (Phys-Chem)Good2015
Dissolved oxygenGood2015
Hydromorphological Supporting ElementsSupports good2015
Hydrological RegimeSupports good2015
Supporting elements (Surface Water)Not assessed2015
Specific pollutantsNot assessed2015
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
Cypermethrin (Priority)Good2015
Other PollutantsDoes not require assessment2015

Protected areas

PA NameIdDirectiveMore information
Solent And Dorset CoastUK9020330Special Protection AreaNatural England
St Albans Head To Durlston HeadUK0019863Special Area of ConservationNatural England

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
RIVER SWAN AT COACH PARK 5003011820142019, 2016, 2014, 20152019
161042 1610422015, 2016, 2014
165063 1650632016, 2019, 2015, 20142019

Upstream water bodies

    Downstream water bodies