Agenda item

2019 Flooding draft investigation report

To consider a report of the Corporate Director for Place Management & Regeneration.


On the last week of July and first week of August 2019, extreme rainfall events hit parts of north-west England and the south Pennines, with flooding observed across Greater Manchester and Cheshire. The main event day was 31st July 2019.


This report presents the various aspects of the flood events in July and specifically incorporates the draft Independent Section 19 Investigation Report in accordance with the Flood & Water Management Act (FWMA) 2010 on the investigation into the flooding events undertaken independently by Mott MacDonald Consulting Engineers.


The Area Committee is recommended to comment on and note the report.


fficer contact: Mark Glynn on 0161-474-3700 or email: or Sue Stevenson on 0161 474 4351 or email:


A representative of the Corporate Director for Place Management & Regeneration submitted a report (copies of which had been circulated) presenting the various aspects of the flood events that occurred on the last week of July and first week of August 2019 and specifically incorporated the draft Independent Section 19 Investigation Report in accordance with the Flood & Water Management Act (FWMA) 2010 on the investigation into the flooding events that had been undertaken independently by Mott MacDonald Consulting Engineers.


The following comments were made/ issues raised:-


·         It was commented that the report identified that the A555 attenuation tanks had been badly designed and it was queried where the responsibility for the design of the tanks lay.  In response it was stated that the tanks on the legacy part of the road had been installed as part of the original build approximately 20 years ago for which Cheshire County Council had been the lead authority.  However, it was clarified that the failure of the attenuation ponds due to design and construction defects had been a more significant factor.

·         There were issues in the construction and design of the A555 that had rectified by the contractor.

·         Concern was expressed in relation to the time that had been taken to replace the failed pumps and controls at the original A555 pumping station at Hall Moss Lane bridge.  In response it was stated that the replacement pumps had been ordered after the flooding event in March 2019 that had exposed the failure of the existing pumps, however due to their nature they were designed and built to order.  The replacement pumps had been scheduled to be installed the week after the July flooding event.

·         The flood warning system had proved ineffective for much of the Stockport area.  It was stated that the warming system was based on water levels in the River Mersey, however the sudden and intense nature of the rainfall was such that the Ladybrook filled quicker and reacted quicker to this, and discussions would take place with the Environment Agency in relation to the appropriateness of the continued use of water levels in the River Mersey as the trigger for warnings across the borough.

·         There was evidence that when residents complained about incidents of flooding, they had been passed around various agencies and it was suggested that there needed to be a more coordinated approach to this.

·         It was queried how the council was going to review its response to road closures during flood events which had been highlighted as an action from a June 2016 report.  In response it was stated that due to the wide area that was covered, it was difficult to manage this across the borough within the resource constraints of the council.  It was stated that a trial was taking place in the Heatons area with regard to the automation of this process.

·         Complex land ownership and riparian responsibilities meant that it was not always possible or practical to check blockages and maintain structures.

·         It was clarified that the alarms relating to the non-functioning pumps on the A555 were still being sent to Cheshire East Council rather than to Stockport, and on investigation after the March incident, it was found that two of the pumps were non-functioning and the other two had failed after which a temporary pump was installed between March and July while replacements were installed.  It was stated that Stockport Council had subsequently taken back control of the pumping station.

·         The report identified that the circuit breakers at the new pumping station were being triggered, and it was not yet clear what was causing the overload.  An alarm system was being installed so that this could be identified early and officers could respond to future such incidents.

·         The report currently didn’t include any timescales attached to the recommendations.  However, when the report was submitted to scrutiny committees and Cabinet later in the year, it would be accompanied by an officer report that would outline the council’s response.

·         There needed to be accountability for the design and build failures identified with the A555 road.  It was commented that the identified defects have been rectified at the contractor’s expense.

·         The report identified that residents should give consideration to implementing flood mitigation measures, however a number of residents around the Bramhall Green roundabout had done so, but were still subject to flooding.  It was further noted that where insurance companies paid for remediation, this would not cover the additional expense of implementing measures to reduce the likelihood of it happening again which was a failing of the existing system.

·         There were a number of bridges in the area that did not have sufficient capacity to allow excess water to flow properly, causing water to back up and then flood.  However, it was commented that there was insufficient funding available to undertake the necessary works to rebuild that bridges that would be necessary to fully resolve this issue.

·         There had been a flooding issue on Highfield Road, Cheadle Hulme caused by culverts that were in private ownership.  The Council had previously tried to engage with residents to ascertain and identify riparian ownership of the culvert, however nine months on from the initial consultation, members were still not aware of the outcome or how the issue was being progressed.  In response, it was stated that there were a large number of culverts across the borough where it was not fully understood where they ran.  Work was taking place on a targeted basis in the worst affected to use CCTV cameras to trace them and understand where they ran and identify any repair requirements.  With regard to the specific issue on Highfield Road, there remained issues with a number of residents who were refusing the council access to their land to establish whether or not they were riparian owners.

·         It was suggested that some of the issues being experienced in Bramhall were as a result of the negligence of the council with specific regard to the silting of the watercourse under the bridge at Bramhall Green roundabout.

·         It was commented that while there would be a public consultation on the findings of the draft report, it was queried how the engagement would work for those residents who did not have access to the internet.


RESOLVED – That the report be noted.

Supporting documents: