It's very grey and gloomy here this morning and we are promised a considerable amount of rain before the day is out.  The river could certainly do with it  as for the first time since about May it's almost unfishable apart from the deeper pools below New Inn.  When the level does come up I intend doing another kick sample in the gravel which was exposed when ewe did the survey last Saturday. 

Looking again at the material that Truro fly fishers sent me I see that they have asked the EA to set trigger levels for their sample sites.  The idea of these is to provide a point at which they would initiate an investigation by the EA.  The idea is that there should be a broadly predictable range of species and population within species for any given river in any given month.  If a survey throws up a result which is markedly different from this predicted norm then the cause would be investigated by an EA biologist.  This is likely to offer a far more immediate indicator of potential problems as the invertebrate population is highly sensitive to variations in water quality and will often show early stages of the development of a problem before the fish show any sign of distress.

When I send our latest batch of results to our EA biologist I will encourage him to consider setting a trigger level for the upper Ribble.  At present we don't have a clear idea just what the norm should be for this river.  I suspect the truth is that, because no one has ever done a systematic invertebrate sample here, no one does and we will need a few years of data to reach a conclusion about a typical monthly pattern.

Ian