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ANNEX 10: SURFACE WATER BIOLOGICAL STANDARDS - BIOLOGICAL STANDARDS FOR RIVERS
Surface water biological standards for rivers in Scotland are presented in Tables A to D below. The standards are presented as 'ecological quality ratios'.
The standards are compared with the measured ecological quality ratio derived by comparing the monitored biological conditions pertaining in the river with the conditions expected under reference conditions.
Reference conditions represent conditions before intensification of agriculture and the development of extensive waste water collection and disposal systems from centres of population. A predicted reference value is used for this purpose. The method for predicting reference conditions is based on data collected from networks of reference sites in the UK or a mixture of sites in the UK and elsewhere in Europe.
Table A: Phytobenthos (i) standards for rivers
Standards for the degree to which the relative annual mean abundances of nutrient-sensitive and nutrient-tolerant groups of diatom taxa differ from the relative annual mean abundances of these groups of taxa expected under reference conditions |
|---|
Column 1 | Column 2 |
|---|
| Ecological quality ratio |
High | 0.93 |
Good | 0.78 |
Moderate | 0.52 |
Poor | 0.26 |
Note to Table A
(i)The term 'phytobenthos' refers to bottom-dwelling multi-cellular and unicellular aquatic plants, such as some species of diatom.
Table B: Benthic invertebrate standards for rivers ( ASPT)
Standards for the degree to which the annual mean sensitivity to disturbance of the observed taxa differs from the annual mean sensitivity of the taxa expected under reference conditions |
|---|
Column 1 | Column 2 |
|---|
High | 0.97 |
Good | 0.86 |
Moderate | 0.75 |
Poor | 0.63 |
Table C: Benthic invertebrate standards for rivers ( NTAXA)
Standards for the degree to which the annual mean number of disturbance-sensitive taxa differs from the annual mean number of taxa expected under reference conditions |
|---|
Column 1 | Column 2 |
|---|
| Ecological quality ratio |
High | 0.85 |
Good | 0.71 |
Moderate | 0.57 |
Poor | 0.47 |
Table D: Aquatic macrophyte(i) standards for rivers
Standards for the degree to which the annual mean abundances of disturbance-sensitive and disturbance-tolerant macrophyte taxa differ from the annual mean abundances of those taxa under reference conditions |
|---|
Column 1 | Column 2 |
|---|
| Ecological quality ratio |
High | 0.80 |
Good | 0.60 |
Moderate | 0.40 |
Poor | 0.20 |
Note to Table D
(i)The term 'macrophyte' refers to larger plants, typically including flowering plants, mosses and larger algae, but not including single-celled phytoplankton or diatoms.
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