Derby County Council
The Rowsley Flood Spans carry the A6 over the River Derwent in Rowsley. The spans are located on the left bank of the channel and become activated during times of flood. Following an inspection in 2017 as part DCCs Principle Bridge Inspection Programme, it was identified that the downstream face of the flood relief spans (constructed of stone blocks) were in poor condition. Repair works were prioritised in DCCs Department Service Plan to avoid a catastrophic failure and subsidence. It was therefore proposed to install 600mm diameter high-strength PVC pipes surrounded with grout infill into each of the spans.
Following consultation with the Environment Agency (EA), hydraulic modelling was necessary to demonstrate that the repair works would not increase flood risk elsewhere. This would be required in order for a Flood Risk Activity Permit (FRAP) to be granted. As such, BWB Consulting were appointed to undertake hydraulic modelling to test the impact of the repair works. Following this, BWB were commissioned to prepare a Flood Risk Assessment in support of the FRAP.
The findings of the study were then formalised in a Flood Risk Assessment that was to be submitted by Derbyshire County Council as part of their application to obtain a Flood Risk Activity Permit for the repair works.