Man-made barriers, obstacles, call them what you will, are commonplace along our waterways as we have (typically) in the past tried to harness or control the flow of water for our own use. Some of these installations were incredibly insensitive to the local and more widely spread ecology and physical processes in rivers and streams, not just the fish that might want free passage both up and downstream at all life stages, and in all seasons.
I recently spent an afternoon with Mike Forty, a PhD student registered at Durham University, and based with the Ribble Rivers Trust. His work, using telemetry to assess the efficiency with which fish can pass obstacles, has been enlightening, and some of the statistics he can rattle off are mind-boggling. His work was featured in the presentation that Jack Spees (Director of RRT) gave at our recent WTT Gathering and captured on video here. For example, the low cost baffle system that was installed on a previously almost impassable weir on Swanside Beck (picture to right) can now be ascended in 23 seconds (according to one sea trout), and several resident brown trout have been up and down it numerous times!
Another of these low-cost baffle systems is being installed on Eshton Beck. Kevin Sunderland (Aire Rivers Trust) has been a driving force for connectivity issues with weirs, not only here, but throughout the Aire catchment. The Canal & Rivers Trust are undertaking the work in consultation with the local Environment Agency and I went along with Pete Turner to see them in action (pic to left). The design was drafted so that the gauging component of the weir would not be affected by any changes in flow over the crest.
This structure is ~0.5km upstream of the confluence with the R Aire, and by my reckoning after a swift glance at a map, should open up ~15km of potential stream network. This could be particularly important for trout and other fish from the Aire that are severely limited in spawning habitat within the mainstem channel. I wonder if Bradford City Angling Association catch returns will demonstrate and noticeable increase in smaller size classes of trout over the next few seasons?
Check out the new app which will hopefully allow the public at large to contribute to identifying and prioritising river obstacles wherever they may be.