If a historic spillway at Marsden is not replaced the risk of the reservoir flooding will be greater than in the Victorian era.
The claim was made by a barrister for Yorkshire Water as a public planning inquiry began into controversial plans for a £6m upgrade to the spillway at Butterley reservoir.
David Manley QC, for Yorkshire Water, told the inquiry at the Media Centre in Huddersfield town centre: “The spillway at present is not fit for purpose.”
He said that without the work “we would be asking the inspector to subject the people of Marsden to a greater risk of flood than their Victorian forebears.”
Yorkshire Water wants to demolish the lower half of the spillway, which includes the stepped cascades, a prominent and much-loved feature, to comply with the Reservoirs Act.
It was in 2009 that Yorkshire Water were told Butterley need attention and that a breach of the dam could result in “catastrophic damage and potential loss of life downstream.”
The plan is to upgrade the spillway with tonnes of concrete but has turned into something of a David and Goliath battle.
A residents group has joined Kirklees Council to take on Yorkshire Water in a bid to save the spillway.
All agree Yorkshire Water need to carry out work to the stunning spillway, but the proposed £6m plan that will partially replace the existing stone spillway with concrete sections is unpopular.
It has been rejected by Kirklees Council which feels it will substantially harm the significance and setting of the Grade II heritage asset.
And concerned residents formed the Save Butterley Spillway (SBS) group to fight Yorkshire Water and say the proposed work lacks quality befitting its listing.
Planning Inspector Jennifer Vyse has been appointed by the Secretary of State to hear the arguments for an against Yorkshire Water’s plan.
Alan Evans, counsel for Kirklees Council, said: “Obviously there is a public benefit to provide a safe spillway for Butterley” but he added that Kirklees does not believe the proposed works are necessary.
“Yorkshire Water has not demonstrated that there are other reasonable means of providing spillway provision to Butterley,” he said.
Diane Ellis, of SBS, heralded it as “the finest and most impressive spillway of its kind in the country” adding they had concerns about the quality of the proposal.
Two of Yorkshire Water’s former employers gave evidence against them yesterday.
Former reservoir worker John Garside was critical of Yorkshire Water for reducing staff in reservoir maintenance and said if they were being “truthful” they would admit they “haven’t had a plan for the Wessenden Valley for 50 years.”
He added: “You say there is no other option, but for Riding Wood in the Holme Valley you left the spillway and built a new concrete one. When you have done an alternative option elsewhere, why not at Butterley?”
Mr Manley told him there was no alternative because a replacement on the same site could not pass a required probable maximum flood test.
Engineer Vin Bamford, also a former Yorkshire Water employer, gave evidence on behalf of Kirklees Council and believes Butterley can operate with reduced flow plus remedial works including grouting and pointing of spillway walls to make it safer.
The inquiry will look at the extent and nature of the harm on the Grade II listed spillway caused by the proposed work, the affect on character and appearance on the landscape and whether the harm it will cause will be outweighed by the public benefit of a new spillway.
The inquiry continues.
Watch: The inquiry getting underway at Media Centre on Northumberland Street