River management and conservation

Members of the BMTF have been carrying out monthly surveys of the invertebrates in the river as part of the Anglers’ Riverfly monitoring inniative since 2011. Although the results from the early years can be ignored thanks to the then lack of experience (!), the regular samplers knowledge has increased dramtically and even the tiniest of stoneflies is unlikely to escape recognition and capture. One of the high points was finding an all-time high of 100 stoneflies in August 2017, compared to a previous high of just 32 specimens.

Stoneflies are found in the Wensum but they are not over-abundant.

The Wensum was one of the river included in Salmon and Trout Conservation UK’s three year River Fly Monitoring Programme as part of its national riverfly census. The project involved three minute kick samples at five different locations in the Spring and again in the Autumn.

A selection of Mayfly nymphs and a large cased caddis pupa.

There are good and sometimes very good hatches of Mayfly from around the second week of May, through June and July and often into August and sometimes September as well when fish will still rise to a Mayfly imitation. At certain times of the season there can be good hatches of caddis and fish will often be seen feeding on hatching caddis pupae as they swim to the surface to hatch.

An Alder (left) and a Cinnamon Caddis.

River Works

Some substantial and extensive river improvements have been carried out by the BMTF and with the Environment Agency. All the river works have been concentrated on improving the riverine habitat for the benefit of the river’s population of wild trout. The BMTF was the winner of the Wild Trout Trust Classic Malts’ 2001 Conservation Award for the Professional Category. This was for work on the Bintry Mill Beat.

The Environment Agency also carried out major work on the river between Yarrow Bridge and County School bridge. The works included re-profiling the river banks; raising the river bed; narrowing the river channel; installing flow deflectors; and creating gravel glides. The true right-hand bank was also fenced to prevent stock damage to the river bank. The Club is working with the Wild Trout Trust on a project to further improve some of these works now that they have matured.

Part of the Yarrow Farm Beat where a gravel glide has been installed. The river bank is now completely re-vegetated.
These flow deflectors on the Yarrow Farm Beat are now all but invisible due to the way they have been colonised by in-channel and bankside vegetation.

Every Autumn, at the end of the fishing season, members of the BMTF spend a number of days water jetting potential spawning areas to reduce the silt in the gravel and to loosen it to make it easier for fish to cut redds. The Club has its own water pump and all the necessary equiment to do this important work.

 

Two redds photographed in December 2015 just downstream from Bintry Mill at the confluence of the main river (on the left) and the mill stream.

 

The latest project is a major restoration of the County School beat which has suffered from historic over dredging and straightening, resulting in a poor quality flow and habitat. It promises to be a long job, but the first stage, clearing the overgrown willows which were blocking much of the channel, has now been completed.

We are now examining options for improving the flow and scouring out some of the river bed to create gravel runs and hopefully new spawning reads. The channel is still too straight for good trout habitat, but there is plenty of large woody debris now available to work with.