Water quality monitoring and investigations
The review of historical information in the FSG
archive has demonstrated that there is very little
historical data on water quality of the Fleet itself
prior to 1996. This is largely because, historically,
there has been no national or statutory requirement
for the Environment Agency (EA) or its predecessors
to monitor water quality of inshore water bodies
such as the Fleet. Data which exist have been obtained
under the requirement for EA to monitor effluent
discharges to freshwaters (i.e. sewage effluent
discharges into the streams entering the Fleet).
Unlike the General Quality Assessments (GQA) for
rivers (see NRA 1994), there is no national surveillance
programme for inshore waters such as lagoons.
The Fleet has now been put forward by the EA as
a >candidate
polluted water (eutrophic)=
to the European Community under the Nitrates Directive
(91/676/EEC) for the review of such sites in 2001.
The selection of the site was a result of concerns
being expressed within the EA, but also by English
Nature and the Fleet Study Group, over the nutrient
status of the lagoon. Identification as a candidate
site does not pre-judge the nutrient status or the
key influences acting on it, but rather acts as
a trigger for further investigation and monitoring
to enable these questions to be answered with certainty.
As a consequence, monitoring of the nutrient status
of the Fleet and its inputs in future will have
a statutory basis, ensuring routine monitoring takes
place. The level of resources employed for monitoring
and reporting will reflect EA regional priorities
and the degree of the problem or potential problem
of eutrophication at the site.
The table below provides an inventory of inputs
to the Fleet. The following sections summarise the
background, methods and results of monitoring or
investigating several of these together with the
Fleet itself in the following order:
Point sources (effluent discharges)
Streams (watercourses)
Receiving waters (the Fleet
itself)
Additional monitoring of point
sources, streams and the Fleet to support modelling
Estimation of inputs from
diffuse sources (including land run-off and wildfowl)
Inventory of inputs to the Fleet lagoon
(based on table 4 from EA 1998a)
Sources
|
Direct
|
Indirect
|
Sewage
Treatment Works |
|
Abbotsbury
STW |
|
Langton
Herring STW |
|
Swannery
Restaurant |
Moonfleet
Manor Hotel |
|
RETC
Chickerell (now revoked) |
|
RETC
Bridging Hard (now revoked) |
|
Watercourses |
East
Fleet stream |
|
West
Fleet Stream |
|
Rodden
Stream |
|
Portesham
Mill Stream |
|
Coward's
Lake |
|
Abbotsbury
Mill Stream |
|
Herbury
Stream |
|
Other |
Wildfowl |
|
Portland
Harbour |
|
Land
Run-off |
Land
Run-off |
Groundwater
flow |
|
Saline
Intrusion |
|
Aerial
deposition |
|
Next Section
References
|