A bridge has been identified as a key cause of some of the flooding that devastated Carlisle last year.

New analysis of the disaster – which saw 2,100 properties inundated in December – blames a combination of unprecedented rainfall and old infrastructure.

The 80-year-old Botcherby Bridge in particular acted as an "obstruction" to river water, contributing to flooding in Warwick Road and nearby. 

Experts say that they will now look at ways to reduce the damming effect caused by both Botcherby Bridge and Eden Bridge, as well as investigating several other key issues to protect the city. 

Earlier this year, Greystone Road resident Keith Evans launched a petition calling for action to improve Botcherby Bridge, describing it as a bottleneck.

The new report as been written by Cumbria County Council, in consultation with the Environment Agency.

It examines some of the reasons why Carlisle flooded, and what action might be needed to prevent a repeat.

The report says: “The 2015 event was of significantly greater magnitude than past events and the flow of the River Eden was the highest ever recorded.”

Experts measure the fullness of rivers by quoting the cubic volume of water that passes a given point in a second. In 2005, the rate of flow per second at Sheepmount in Carlisle was 1,516 cubic metres of water. In December, the flow rate has risen to 1,680 cubic metres. In 2005, 1,600 properties were flooded but last year's flood inundated 2,100 properties were inundated.

To help prevent future flooding the report recommends:

  • Reviewing the potential to improve flood defences around Botcherby Bridge
  • Reducing the obstruction caused by bridges
  • Looking at the case for flood defences in Rickerby village. BLOB Extending defences at Viaduct Road Estate to prevent flooding from the nearby railway line
  • Reviewing the defences at Etterby Terrace to mitigate flooding from Gosling Syke
  • Reviewing the resilience of the area's two Environment Agency pumping stations.

Findings will be discussed at public meetings in Carlisle next week.

Organised by Cumbria County Council, they are the second stage of a process that started in March with two events where people were asked about how and when their properties flooded.

Doug Coyle, the authority's Local Flood Resilience Manager, said: "The description of how Carlisle flooded has clearly highlighted different areas that could be the focus of future flood defence work, but we need to hear local people’s views before we can move forward and agree a final report.

“I hope people will attend the meetings and share their views. People can also comment online if they are unable to attend.”

Kath Tanner, the Environment Agency’s Flood Recovery Manager, said: “Once finalised, the reports will inform future plans and help us make Carlisle more resilient to flooding."

The draft Flood Investigation Report is now published at http://www.cumbria.gov.uk/floods2015/floodforums.asp . 

Comments on the report can be emailed to LFRM@cumbria.gov.uk or sent in writing to Local Flood Resilience Manager, Environment and Community Services, Parkhouse Building, Carlisle, Baron Way, CA6 4SJ.

The Flood Forum events will be on May 9, at Holy Trinity Church, Wigton Road, Carlisle; and on May 11, at the University of Cumbria, Fusehill Street, Carlisle.

The programme is:

  • 5-7pm: Information available around resilience grants, Flood Re & general enquiries
  • 7-8pm: Presentation of draft Flood Investigation Report with feedback and questions
  • 8-9pm: 1 to 1 discussions with officers for additional data collection