Overall Water Framework Directive Status / Potential 2009 – 2012 of the Deben catchment including associated tributaries, with brief summary of reasons for failures.
Deben Catchment
Overall Status/ Potential
WBID
Commentary
Name
HMWB
2009
2010
2011
2012
GB105035040200
King's Fleet
No
Moderate
Moderate
Moderate
Moderate
Previously classified by Expert Judgment (Hydromorphological results only). Chemical ESI monitoring implemented for 2013.
GB105035040240
Deben (Tidal)
No
Moderate
Moderate
Moderate
Moderate
Waterbody will not be included in 2nd River Basin Planning Cycle
GB105035040250
Deben (Tidal)
No
Moderate
Moderate
Moderate
Moderate
Waterbody will not be included in 2nd River Basin Planning Cycle
GB105035040260
Deben (Tidal)
Yes
Moderate
Moderate
Moderate
Moderate
Waterbody will not be included in 2nd River Basin Planning Cycle
GB105035040270
Deben (Tidal)
No
Moderate
Moderate
Moderate
Moderate
Waterbody will not be included in 2nd River Basin Planning Cycle
GB105035040280
Bucklesham Mill River
No
Moderate
Moderate
Poor
Poor
Failure driven by moderate to poor fish status. Failure has been investigated and local expert judgment believes the trout dominated
community to be desirable, more so than achieving ‘good’ WFD status. The less than good status is considered likely to be due to the trout
(BAP species) out-competing the expected coarse community. Excellent Brook Lamprey numbers, another BAP species.
GB105035040290
Shottisham Mill River
No
Good
Good
Good
Good
Invertebrates at Good status, all physchem monitoring at High status (including dissolved oxygen and phosphorus)
GB105035040300
Lark/Fynn
Yes
Moderate
Bad
Poor
Moderate
The apparent deterioration in overall classification is due to the 2010/11 hydrology assessments indicating flow non-compliance. This
means that the bad/ poor fish classification is taken in to account in the overall classification, whereas previously the fish status was not,
as per the classification methodology for heavily modified waters. The flow is compliant in 2012 so the biology can no longer drive the
overall classification, hence moderate.
GB105035040330
Fynn
No
Poor
Poor
Poor
Moderate
Failure driven by poor fish status with associated hydrology and phosphorus failures. Habitat quality and availability were cited as reasons for the fish
failure together with ammonia leaching from a landfill site in the mid reaches. Hydrology considered to support Good status.
GB105035040340
Tributary of Deben
No
Moderate
Moderate
Good
Moderate
Waterbody previously grouped. Diatom monitoring introduced in 2010 resulting in Good 2011 classification. Although diatoms still at Good in 2012
introduction of chemical monitoring, specifically dissolved oxygen, reduces overall classification to moderate.
GB105035040360
Lark
No
Moderate
Poor
Poor
Moderate
Fish status has changed from moderate to poor back to moderate (this appears to be an issue with the model) investigation cited water quality and
sedimentation as reasons for the failure. New diatom monitoring in 2010 resulted in a moderate status. Ammonia and phosphate failures attributed to
a large unregulated discharge in the catchment, treatment limits to be put in place by October 2012 hopefully leading to water quality and ecological
improvements.
GB105035040370
Tributary of Deben
No
Moderate
Moderate
NYA
NYA
Renamed as Potsford Brook for RBMP2. Waterbody previously grouped, link dropped in 2011 so overall status Not Yet Assessed. ESI monitoring in
2012 will inform 2013 classification.
GB105035046140
Framsden Watercourse
No
Moderate
Poor
Poor
Moderate
Waterbody previously grouped, link dropped in 2010 with the addition of diatom monitoring and resulting poor status. The diatom data has not been
carried forward into the 2012 classification so the resulting moderate status is driven by failing dissolved oxygen within the waterbody.
Bad
Waterbody previously grouped both for chemical and biological elements. 2011/2012 classifications are driven by new diatom monitoring resulting in
bad status together with moderate fish status and poor dissolved oxygen and phosphorus results from new monitoring sites. Fish failure is attributed
to 14 impassable barriers. Historic low flowing river resulting in dissolved oxygen problems but measure already in place with compensation flow
provided from Earl Soham borehole during these events.
GB105035046160
Deben
No
Poor
Poor
Bad
GB105035046200
Deben
Yes
Poor
Poor
Poor
Poor
Failure driven by poor diatoms and fish status. Invertebrates, dissolved oxygen and phosphorus also failing. Diatom failure confirmed and linked to
phosphorus failure. Inputs of diffuse and point source pollution have been identified and improvement measures will be investigated. Invertebrate
monitoring is undertaken in an ephemeral stretch resulting in a specialist community, these sites have been dropped from the WFD programme. The
fish failure is linked to the dissolved oxygen and phosphorus failure which leads to overgrown and heavily silted reaches.
GB105035046210
Earl Soham Watercourse
Yes
Poor
Poor
Poor
Poor
Failure driven by poor diatoms and invertebrates with associated poor phosphorus. Diatom failure confirmed and linked to phosphorus failure.
Sources of diffuse and point inputs have been identified and improvement measures will be investigated. Invertebrate status based on a site
immediately d/s of a sewage treatment works (ephemeral above), this site was not used in the 2012 classification.
Poor
Failure driven by poor diatoms and fish with an associated moderate phosphorus failure. The diatom failure has been investigated using
the new National tool and the status is considered to be Good. Similarly, a phosphorus investigation with multiple monitoring points
indicates Good status. The fish failure is attributed to lack of habitat availability and by the absence of trout in this predominantly
ephemeral watercourse. Wider catchment issues as main river has 14+ barriers with linear ponded sections making it highly unlikely that
trout will successfully migrate upstream. The cost effectiveness of facilitating fish passage throughout may hinder progress to Good.
GB105035046310
Deben
Yes
Poor
Poor
Poor