Case study
Significant flooding has occurred in Leatherhead and Fetcham over many years. The Environment Agency (EA) investigated a number of options to reduce fluvial and surface water flood risk and Property Flood Resilience (PFR) was found to be the preferred way forward for some areas.
JBA was appointed by the EA in 2019 under Lot 1 of the PFR Framework to provide hazard assessments and property surveys to residential properties in the area. In total, 85 properties out of 102 registered an interest in the scheme and surveys were undertaken.
Fluvial and surface water flooding is the main flood risk in Leatherhead and Fetcham. We used the Middle Mole hydraulic model to assess the fluvial flood risk. We also utilised the EA’s surface water flood maps and flood history to assist us with our hazard assessment. Threshold survey was provided by the EA which we used to compare with property specific flood levels. This allowed us to calculate the standard of protection required to align with the wider scheme and confirm eligibility.
Conversations were held with each resident to fully understand property-specific flood history. Most of the buildings were found to have been heavily altered, with many having numerous extensions, converted garages and single skin brick porches impacting the suitability of some PFR measures. Initial conversations were also held with homeowners to understand the suitability of PFR measures that may be available (for example the pros and cons of flood doors (image 1) and flood barriers (image 2)). This meant the homeowners were able to consider what would be suitable for them and the outcome would be delivered in line with their expectations.
Non-return valves were also considered as part of the scheme.
We built up a comprehensive picture of flood risk, identifying options to better protect and reduce the risk of future internal flooding for each individual homeowner. We emphasised the importance of sourcing products that carry a BSI Kitemark Certification where appropriate, to ensure best practice and standards are maintained throughout the scheme. A number of properties in Leatherhead and Fetcham had PFR measures installed prior to the scheme which were not Kitemarked. We recommended that these were replaced with Kitemarked products to ensure the quality of the measures available to the homeowner. The client was also fully involved in the options process from an early stage, so the most appropriate PFR recommendations could be agreed.
Detailed property specific PFR survey reports were prepared which identified flood sources and all ingress points, with outline mitigation recommendations and detailed pricing schedule included.
JBA undertook the hazard assessment, property survey, assessed options, prepared an outline design and post installation audits in line with the PFR Code of Practice.
Once the PFR measures were installed and confirmed as complete by the installer, we were able to undertake post-installation audits.
To reduce the disruption to homeowners, the installer completed their final sign-off on the same day we undertook the post-installation audit. We stressed the importance of our audits being independent of the installer and we did not attend the same property at the same time. A further benefit of this approach was that any issues identified by JBA could be dealt with on the same day by the installer. The client also accompanied our team to visit each property to witness successful completion.
70 properties received PFR measures and have been audited.
The Covid-19 pandemic started shortly after the installation contractors were appointed. We had to develop new safe working practices and methodologies when auditing the properties as to avoid enter buildings.
The Covid-19 pandemic brought significant challenges in terms of programme which meant some residents had relocated and therefore we had issues making contact to arrange appointments for the post-installation audits. Where up-to-date contact details were not available, we sent an initial letter outlining the details of the scheme and the benefits of the post-installation audits. The letter also asked the new homeowners to call us, to book an appointment and we successfully audited most properties. However, there were a few homeowners which did not make contact. Therefore, we undertook a door knocking exercise to discuss the scheme and the benefits of the audit. In some cases, the homeowners allowed us to undertake the audit on the same day, otherwise we were able to book an appointment for an alternative date. Where there was no answer, we left a letter asking the homeowner to contact JBA to make an appointment which proved to be successful.
Being prepared for potential flooding is an important element of being flood resilient as it leads to approaches to use PFR measures. It’s about understanding your flood risk, now and for the future.
