Good Friday: a good days sampling on the Upper Lea
On Good Friday, Riverfly monitors for the Upper Lea David and Charlotte had their best sample yet.
At East Lane Carpark in Wheathampstead where Riverfly monitoring is being used to monitor an upcoming restoration project, sampling on Good Friday brought in 60+ caseless caddisfly larvae. Tree works have already been completed on the site and the extra light reaching the river is already letting instream vegetation start to grow with the first shoots of ranunculus showing. Within the site the only real flow diversity comes from a "kiddie weir" (where large stones have been placed along the width of the channel like those made by children playing in the river during the summer months). It is suspected it was the kick sampling and rock search at this point that turned up the most inverts and the project about to begin to install flow deflectors along the stretch will help to replicate this and create further habitat for Riverfly species. The microhabitat of the "kiddie weir" also turned up a handful of stone loach whilst cased caddis larvae, gammarus and olive nymphs were also counted.
Downstream at their second monitoring point at the Meads, the monitors had the opportunity to engage in a spot of community education. The Meads is a picnicking hotspot for families during good weather, and the blue skies and warm weather of Good Friday allowed for an impromptu Riverfly demo to a number of families who were enjoying themselves along the bank of the River Lea. Both children and the monitors were far from disappointed with their sample of 250+ olive nymphs, 200+ gammarus, cased and caseless caddisfly larvae, a solitary mayfly nymph as well as the first blue winged olive nymphs of the year.