Why more reservoir water is needed for flood alleviation trials

Widdop reservoir in fuller times. It is hoped more flood alleviation trails will take place when water stocks recovery from the dry late spring and summer

Calderdale Flood Recovery and Resilience Board heard at its last meeting in June that only small events had occurred in the winter 2017-18 trial but lower reservoir levels – these had been managed down to 90 per cent of their usual top storage level – did provide a significant impact on peak flows in Hebden Water for the largest of these.

READ: Rangers patrolling Calderdale beauty spots to keep people safeHebden Water feeds into the River Calder at Riverside in the town centre.

Following these initial assessments the model for the scheme has been updated to include Yorkshire Water’s observations, further supporting that it performs well.

READ: Ogden Water has been named Yorkshire’s favourite reservoirHowever more testing is needed but because of the dry summer Yorkshire Water is not in a position to be able to commit to a further trial this winter – this will effectively be dictated by the level of reservoir recharge across the whole region in the coming weeks, board members were told at its September meeting.

This is because water resources in one area can be and are used by Yorkshire Water to supplement other areas where resources are stretched.

Further testing will help establish what needs to be achieved in terms of water level and volume control at the reservoirs, enabling well-founded budget costs to be identified.

The report to the board said: “Clarity and certainty on cost is crucial to understanding the feasability of progressing capital works.”

The board and YW remain keen to progress the tests – but they will need more rainfall first.