This is a program that can be used to find an index of quality of a freshwater river or lake. It was developed by the Severn Trent Water Company. It depends on the fact that the purer water is:-
1. It has more species of animal present.
2. Certain indicator species also indicate pure water.
A simple count of species is not enough to assess water purity, as polluted water for instance may contain many species of perhaps midge larvae, but could by no means be considered clean, as other creatures could not survive in it. Therefore a more complex system was developed that produces an index reflecting the two above facts.
An index of 1 is very low, and the purest freshwater systems have an index of 15.
The Program
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A simple window opens when you click on the icon bar icon. The named creatures represented in the top part of the window are the indicator species. These are ticked if they are found to be present in the water. In fact however only the highest creature ticked, has a bearing on the index.
A simple set of arrow bump icons can be used to enter the number of species discovered. Strictly these should only be invertebrates, but different species in the same family should be included. Indicator species should also be included in this total.
Copyright
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This program is Public Domain. It may be distributed or copied freely as
long as no part of this software may is used in any other program, whether
commercial or public domain,without my prior written consent, though any
files created by this software are not bound by this condition. This
software may not be distributed for a profit, save that required to cover