Could canals help to divert water from flood-risk areas?

In view of recent weather-related incidents, Ivor Caplan, IWA nominated trustee for the Lichfield & Hatherton Canals Restoration Trust, asks whether canals can help to reduce flooding.

THE high levels of rainfall in early 2024 may have made you wonder how the inland waterways, and specifically the results of our restoration efforts, can contribute towards mitigating flood risk.

From my own experience, completion of the Droitwich Canals Restoration in 2011, partially utilising the River Salwarpe, contributed to reducing the flood risk in Vines Park and the town centre.

Our canals are artificial channels which cut through the natural drainage paths and with the right investment they could play a role in mitigating flood risk. They have the potential to intercept drainage, hold up flows and move even more water away from towns and properties at risk, to stop houses and businesses from being flooded.

There is also the potential for many of our structures in rivers (weirs, sluices and locks) to be modified to improve flood risk management. Perhaps worth considering in the future restoration of Lichfield & Hatherton Canals Restoration Trust locks is whether weirs can be designed with a greater range of outfalls to allow for varying flow conditions.

This construction may assist in alleviating surface water flooding through acceptance and conveyance of surface water discharge which would also provide a source of water to top up canal water levels when required. Appropriate sizing of new culverts for existing watercourses could be used for attenuation of water course peak flow rates.

Although our canal can help to alleviate flood risk, we should also be aware of the risk to the restored channel and towpaths from possible overtopping in flood conditions which has been experienced elsewhere. All issues for us to consider, as it seems likely that climate change will cause the UK to experience heavier rainfall and higher sea levels, leading to an increased flood risk in future.

This article, which first appeared in the L&HCRT’s newsletter Cut Both Ways, has been reproduced by kind permission of Ivor Caplan.