- 25th November 2016
- Posted by: Joanne Woodhouse
- Category: Projects
A feasibility study and options appraisal for the Environment Agency into the removal of floodbanks on the River Derwent upstream of Kexby Bridge near York.
The River Derwent at Kexby is embanked with the floodplain on both banks being disconnected from the channel. The floodplain at Kexby is disconnected because there are floodbanks between the river and the adjacent floodplain, i.e. when the river rises it does not spill onto the floodplain until it overtops the banks. A connected floodplain would flood as soon as the river bank is full.
These floodbanks were only constructed in the 1990s and were identified in the Derwent River Restoration Plan as being suitable for removal. The floodbanks themselves were constructed by the landowners, therefore, there was no record of what they were constructed from.
We were commissioned to undertake a full options appraisal on the reach to include a full topographic survey, utilities search, cultural heritage assessment, soil sampling and an eco-geomorphological survey of the river. Following this, several options for the reach were developed and then discussed with the landowners before they were presented to a stakeholder group meeting. This led to the detailed design of a preferred option ready for implementation. The design chosen was the breaching of the floodbanks on the left bank upstream of Kexby Bridge and the creation of a backwater within a new wet woodland, a habitat lacking on the lower Derwent.
This will allow existing woodland areas to be connected-up providing spawning areas for juvenile fish and resting and nesting locations for species such as Otter and Kingfisher.
For more information: Kieran Sheehan