| BMWP
Scoring - Measuring Freshwater Quality
Freshwater
macroinvertebrates require various given amounts of dissolved oxygen in
stream water in order to live, and organic or chemical pollution will
reduce the oxygen level of water.
We use this
knowledge, together with something called the Biological Monitoring
Working Party (BMWP) scoring system to evaluate a stream or river and
assign a quality category to it.
BMWP scores
reflect the sensitivity of macroinvertebrates to oxygen depletion.
So the number and type of species in the stream is a good
indication of whether it is impacted by organic or chemical pollution.
The
quality category is based on the scale below:
|
BMWP
score
|
Category
|
Interpretation
|
|
0-10
|
Very
poor
|
Heavily
polluted
|
|
11-40
|
Poor
|
Polluted
or impacted
|
|
41-70
|
Moderate
|
Moderately
impacted
|
|
71-100
|
Good
|
Clean
but slightly impacted
|
|
>100
|
Very
good
|
Unpolluted,
unimpacted
|
|
