Throughout the River Witham a variety of works will focus on improving the channel, with the intent to restore the straightened, over-widened sections of the river into a more natural environment with more in-channel variation.
By creating this natural in-channel variation, the habitat will be greatly improved, leading to an increase in species abundance and diversity.
These in-channel improvements are chosen because they are able to protect and enhance the existing habitat of the river, while maintaining its course through Grantham which is largely constricted by hard banks throughout the town.
These exciting restoration works will involve the planting of native species, encouraging the presence of protected and scarce animals, such as white clawed crayfish and grey wagtails, which have limited habitat in the area.
The works have been designed to work in both low flows and high flows so in times of drought a narrower channel concentrates flow helping to keep fish and other aquatic organisms happy. In times of high flow, the works are drowned out and don't impact on flood risk but still provide areas of refuge for aquatic species.
Notably, the white clawed crayfish is an important species to provide high quality habitat for, since it has been in decline in the UK since the 1970’s. The River Witham is one of the largest and last strongholds of these important native white clayed crayfish in the UK, containing tens of thousands within it and its tributaries.
As, in most areas the native white clawed crayfish has been outcompeted by the invasive American signal crayfish, creating favourable habitat for our native crayfish is extremely important to ensure their survival.
Additionally, BAP species like Brown Trout will also benefit from increased marginal vegetation which provides food and refuge opportunities, as well as the addition of gravel for spawning.
As well as creating an increase in high quality habitat in the channel, these improvements will also benefit the community as the river will be more aesthetically pleasing and a more interesting area to either commute or to use for leisure such as riverside walks.
Previous in-channel restoration works along the River Witham, at Wyndham Park