In a healthy river most of the pollution sensitive invertebrates (the target groups) should be present (although may not be found naturally throughout the year - eg BWO's mainly found late Spring-Summer).  Declines in water quality are reflected in declines in the abundance and number of different invertebrates present.  Sampling a site on a monthly basis (which is generally not possible by the Environment Agency) provides seasonal baseline data from which severe changes in water quality can be easily identified.  As well as giving information useful in determining long term trends, the setting of a "trigger level" at each site (typically an ASI of 4) allows severe perturbations in water quality to be identified.  If the trigger level is reached then  an agreed call-in procedure will allow the Environment Agency to take early action to investigate.  It should be understood that natural changes in abundance or indeed presence/absence of target groups may occur from month to month (seasonal life cycles etc) or perhaps due to washout by high flows.  The Trigger level of ASI 4 is likely to mean a severe water quality problem however.
There are locally agreed procedures for collating results and communicating these with the Environment Agency contact.  In some areas a regional coordinator may collate results from a number of monitoring groups and pass results onto the Agency contact at agreed intervals.  Should a trigger level be reached however then this would be reported to the Agency contact as soon as possible.  The data is held by the angling organization and shared with the Agency.

More information on the Riverfly Partnership may be found at www.riverflies.org  It is planned to have a Cumbrian Riverfly page and a database of collated results.

Introduction to River Bela Riverfly Monitoring
Following the successful South Cumbria Riverfly Partnership training days in April 2007, an approved routine monitoring site on the River Bela u/s A6 Bridge at Beetham (SD 497 797) was set up by Milnthorpe Anglers.
There is an Environment Agency routine monitoring site approx. 200m further upstream (SD 498 795).  This site has been sampled more or less twice yearly since 1990 allowing target and trigger levels to be set for the Riverfly monitoring site.

At present four pairs of anglers are monitoring the site on a proposed monthly schedule (Spring/Summer and Autumn). It was agreed that Peter Moreton from Milnthorpe Anglers  would collate the results for the site and send them to myself as the Environment Agency contact.  To date 5 sets of samples have been sent to the Agency with a total of eight participating anglers working in pairs on a monthly rota system.  Our thanks must go to those anglers:

Ian McMurdo & John McKay
Peter Moreton & Paul Proctor
Steve Trafford & Jack Holmes
Keith Rodgers & Brian Pickthall

Environment Agency Routine Sampling Site on the Bela
Our routine biological monitoring site (N498) is approx. 200m u/s the A6 bridge at Beetham (SD 498 795) and has been sampled on a regular basis since 1990.  Over the years, this sample site has been routinely monitored for a number of reasons - GQA (General Quality Assessment), CAMS (Catchment Abstraction Monitoring Strategy) and also recently for WFD (Water Framework Directive) purposes.

The sampling methodology is the same as for Riverfly monitoring - 3 minute kick sample followed by a 1 minute hand search.  For the most part, sampling has been twice a year  - Spring (March - May) and Autumn (September - November), although on five occasions a Summer (June-August) sample has been taken.  For the most part, samples undergo an initial bankside assessment before being preserved and laboratory sorted at a later date.  Samples taken between 1990 and early 1992 were field-sorted only.

Results generally indicate a productive, mildly enriched watercourse. There have been historic sheep dip problems further up the catchment but to date there have been no recorded impacts at this site.  The monthly sampling by Milnthorpe Anglers will identify any major problems outside the Agency sampling programme.

Samples from routine site N498 are sorted to a mixed taxonomic level, but it has been possible to produce ASI's by extracting abundances for the 8 Riverfly groups:

Spring  - 17 samples with ASI's ranging from 9-17, average 13
Summer - 5 samples with ASI's ranging from 13-19, average 15
Autumn - 16 samples with ASI's ranging from 10-18, average 13

From these results it seems sensible to set a Target level of ASI 13 for the Riverfly monitoring site.  A Trigger level of 4 is being set for all sites unless there are other circumstances (eg the very impoverished sites on the Duddon catchment which are probably subjected to occasional acid-stress).

For information and of potential interest  to the anglers, a list of further identified taxa within each of the target groups is given in Appendix 1