BART have been very busy recently, travelling all over the catchment doing walkover surveys and writing advisory reports for river improvement projects including the Corston, Newton, and Nunney Brooks and the River Somer. Jess, our Aquatic Scientist, has found many issues on the Nunney Brook including channel straightening and re-enforced banks which means there is limited bankside and in-stream habitat. She also found sections of the brook were overly deepened, sluggish, full of sediment and heavily shaded, preventing light from reaching the channel. These factors will reduce water quality and productivity in the channel, suppressing invertebrate populations due to lack of habitat and food sources which in turn reduces populations of other river wildlife.
Over-deepend, straightened and channelised section of the Nunney Brook
More survey work took us to a section of the River Avon near Sherston, Wiltshire, where we spent a beautiful evening assessing numbers of spawning Brown trout. We marked the locations of ‘redds’, which are depressions dug by the Brown trout into which they lay their eggs. This survey followed concerns of reduced numbers of the fish each year along with lower water levels. We are planning to put in some woody debris structures here next year to increase the diversity in water depth and flow, which will also help to scour the riverbed gravels of sediment which can smother the fish eggs and reduce spawning success. To best position the woody debris structures to give the greatest benefit we are going to be monitoring locations of the redds over the winter.
A beautiful evening for survey work!
