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SUDS
Performance Data 2003
Using the
partnership's 2003 water quality sampling results, the Environment
Agency (EA) analysed SUDS performance in 2003, comparing
the newly
created SUDS with two well-established on-line ponds further
downstream.
In
brief, the EA's analysis of our water quality
sampling for 2003 found:
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Faecal coliforms
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Ammonia
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Nitrates
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Suspended Solids
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BOD
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DO
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SUDS
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significant decrease
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significant decrease
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_
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_
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significant decrease
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significant decrease
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Coy Pond
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significant increase
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significant increase
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_
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significant increase
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_
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significant decrease
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Alder Road Pond
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_
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_
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significant decrease
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_
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_
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significant decrease
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BOD
= biochemical oxygen demand
DO
= dissolved oxygen
The
'significant decreases' in faecal coliforms, ammonia and BOD at the SUDS
site is a triumph! Evidence of this can be seen in the graphs
below.
Decreases
in suspended solids was good, but couldn't be called significant.
Nitrates are not a significant contributing factor to Bourne stream
diffuse pollution problems (classified as 'moderately
low') and so those results are not a disappointment.
The
increases in coliforms, ammonia and suspended solids at Coy Pond are the
result of the polluting effects of large numbers of waterfowl on a
typical municipal pond; in contrast the SUDS at Alderney and Alder Road pond,
whilst both supporting some waterfowl, feature reedbeds and
vegetated margins which have a beneficial effect on water
pollution.
All ponds appear to have a
detrimental effect on levels of dissolved oxygen; this can be
overcome by creating weirs and other oxygenating features
in-stream.
Further
evidence
Charts below illustrate mean
data collected over 15 weeks between 28 May - 10 September, including the
sampling during heavy rainfall on 28 August.
 Significantly, the SUDS demonstrate
successful treatment of bacterial pollution (total and faecal coliforms
and enterococci, ammonia and BOD (biochemical oxygen demand).
To
locate the three SUDS sampling sites referred to in the charts
below, see the enlarged plan
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