Croston flood defences defended by the Enviornment Agency

It comes after the Lancashire Post revealed that people living in Croston had been left in a state of panic on Sunday evening after a period of torrential rain caused a sharp rise in the level of the River Yarrow, which runs through the village.

However, the £7m flood defence system installed in the area six years ago took four-and-a-half hours to be operating at its full extent, according to the volunteer-run Lower Yarrow Flood Action Group. That is because the dam closes in several stages, with a mandatory 90-minute gap between each of them.

Flood group co-ordinator Richard Guinness told the Post that he heard people “screaming” in fear during the course of the evening as they witnessed the river level increasing - and the risk to their properties growing with it. Against that alarming backdrop, they were unable to understand why it was taking so long for the complete closure of the dam, which is located upstream of Croston, towards Eccleston.

While acknowledging the expertise of the EA, Richard said that if the system operated more “aggressively” than it does at the moment, “then we wouldn't have had the problems that we had last weekend”.

Those problems included the flooding of around half a dozen properties - although the EA has now told the Post that those incidents were as a result of surface water flooding, which is a local authority responsibility. The agency said that there was no flooding from the river over the weekend - and so the damage caused was not related to the response time of the dam.

The EA also stressed that the current timings for the operation of the flood defence system were planned to reduce flood risk as far as possible.

An Environment Agency spokesperson said: “Following heavy rain last weekend, the Croston Flood Alleviation Scheme proved effective in holding back a large volume of water, protecting properties in the village against flooding from the river.

“While we understand residents’ concerns about the time it takes to close all the floodgates, it is important to realise that this has to be done in stages to minimise the risk of flooding and make sure that people and properties are protected.”

The Post understands that increasing the operational speed of the gates would mean that the flood basin created as part of the defence system would fill up faster - and, because of its limited capacity, would be more likely to overspill during prolonged rainfall events, ultimately causing further flooding.

On Boxing Day back in 2015, 340 properties in Croston were flooded following a storm, a disaster which led to the installation of the flood defence system - with a capacity of 520 Olympic-sized swimming pools - 18 months later.

The EA’s spokesperson added: “People can sign up for free flood warnings and keep up to date with the latest situation at https://www.gov.uk/check-flooding, call Floodline on 0345 988 1188 or follow @EnvAgency on Twitter for the latest flood updates.”‎

HOW DOES THE DAM WORK?

During a flood event, when the flood basin is used, the gates of the dam are closed in sequence. Their operation is automated and determined by the flow of the river at Castle Bridge Weir in Croston.

Signals from the river flows measured in Croston dictate if the gates continue to close or go back to an open position if river flows have improved. As the flood basin fills, the Environment Agency gives notice to landowners to clear livestock from the area.