Starting Work on The River Went in Yorkshire
Posted on April 18, 2017
Although this is the start of what is planned to be a wider project that tackles multiple issues throughout the full length of this heavily-modified river, the first set of works are shaping up really pleasingly.
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It was particularly impressive due to a last minute loss of the previous project manager due to a career move. In the video you can see how Alec worked with the WTT to power through the first, steep part of the learning-curve on in-river structural improvements to a heavily-modified river.
The main challenges stemmed from the historic realignment of the channel (and general lack of in-stream structure/debris necessary to create vital habitat for different lifecycle stages of fish and other aquatic life). Coupled with the relatively low gradient and fine particulate material/potential associated diffuse-pollution inputs from upstream, this had made the channel very uniform (boring) and also lacking in diverse substrate (bed material).
While the future parts of this project will explore ways of improving land-use (and other measures) to reduce the particulate material runoff, the creation of alternating scour and deposition in this section should significantly increase the complexity (and hence value) of the habitat here. There is also, now a massive amount of extra cover from predation — which will help to keep populations of predators and prey in a more resilient balance.
The increased complexity (and scour/deposition processes) were complemented by the “seeding” of gravel upstream of some of the new “roughness-generating” structures in the channel. Spate flows redistributing that gravel should mimic the creation of spawning conditions that have been historically cut-off by changes to land-use (open-cast mining has inverted top and sub-soil horizons in the upper catchment!).
Natural gravel inputs have also been constrained by the channel being straightened and locked in place. Normally, the gradual movement of a channel across a floodplain would cut into gravel “lenses” in the banks and continually replenish supplies to species that need gravel to breed.
You can see Alec describing this first phase of works in the embedded version of the video here: