The Black Sluice IDB has just completed initial works with the Environment Agency using a small scale cutter suction dredger provided by Smals Dredging UK Ltd to carefully remove silt deposits from the bed of the South Forty Foot Drain, near Boston in Lincolnshire. The aim of the work was to restore the capacity of the channel within the 17th century raised bank main river to improve conveyance. This first phase of works took place over 7.5km of channel between Neslam Bridge and the Board’s Black Hole Drove Pumping Station and the future intention is to continue this work through to the A17 Swineshead Bridge.
Silt was pumped up to 3km through pipes floating in the channel to two dewatering areas constructed on adjacent farmland. Here the silt settles and the clean water is fed back into the river. Once dried out the silt will be reworked into adjacent farmland and the lagoons returned farming. Water quality, fish and other environmental criteria are being carefully monitored as part of the work.
As part of the project the IDB and Smals Dredging held an open event to explain the specialist technique being used to other flood risk management authorities and the general public. Across the two days over 200 people attended. It is hoped the project demonstrates that the technique offers substantial benefits over more traditional methods to remove sediment from lowland watercourses in terms of cost and disturbance to the local environment and communities where conditions allow.
All of the works are being carried out within the Public Sector Cooperation Agreement between the IDB and the Environment Agency.