Flood Map Challenge – where are we now?

Technical Director, Olivier Saillofest shares the latest on the Flood Map Challenge and provides advice on how to attain updated flood maps.

Case Officers use the Flood Zones 1, 2 and 3 to confirm whether a proposed development passes the Sequential Test and should be granted planning approval. Notwithstanding a small number of cases where Councils use their own SFRA flood maps, Flood Zones 1, 2 and 3 are predominantly produced by the Environment Agency and can be seen on their Flood Map for Planning website. When preparing a planning application these maps are used by developers to confirm what proportion of their site is developable, which part should be allowed to flood, and what types of flood mitigation measures should be used.

In a county with growing housing needs and targets, optimising the development potential of sites has triggered the need to refine and improve the accuracy of these maps, generally using detailed hydraulic modelling techniques.

But how does one get the Flood Map updated with new detailed model results, or following mitigation and development?

“A Flood Map challenge” I hear you say – “Not so simple!”.

With the current pandemic, the Environment Agency’s resources have been stressed and the flood map challenge process has been on hold for approximately 6 months. The latest update I received is that:

“There are two different routes to get the flood map updated:

If it is a standalone flood map challenge not related to an ongoing planning application, then the request will go to our Evidence and Risk (E&R) team. Unfortunately, E&R are currently not processing these requests and there is no timetable for when it will be reviewed.

If the flood zones are changed as part of a planning application, then E&R will review the model as it is part of our statutory response to planning applications. Assuming the model is approved then it is passed to our area flooding teams to update the flood maps. Our flooding team would need evidence that any necessary construction works have been completed in accordance with the plans. Unfortunately, this process is also currently not being undertaken due to resourcing issues. However, I understand the flooding team is currently trying to recruit the necessary resource that would support this service again.”

Not ideal for the developer, especially if their development site involves units shown within the EA Flood Zones 3 and 2 (as shown on the Flood Map for Planning website) despite results from the detailed modelling showing otherwise.

How will the developer demonstrate to potential buyers that it is worth investing in one of their plots, and that they will be able to insure the property?  Sure, presenting them with the Flood Risk Assessment or the hydraulic modelling report that accompanied the planning application for the site is on option – if they are familiar technical wording such as “digital terrain models”, “hydro-dynamic modelling parameters”, “annual exceedance probability”. No wonder less technically minded persons may choose to walk away from the sale!

With the number of flood map challenge requests piling up and no clear indications on when the Environment Agency flood map challenge process might resume, house builder’s sales departments should clearly prepare to work overtime to sell their plots.

Luckily, the Environment Agency’s Flood Zone maps are not the only flood risk datasets being used by potential buyers and their solicitors to identify the risk associated with their investment as part of a house purchase.

Homebuyer search reports consider alternative flood map datasets specifically produced for the insurance industry. Following years of dialogue with house builders, JBA Risk (market leader in the production of insurance flood maps), in consultation with JBA Consulting, have developed tools to edit their flood maps and take into consideration the standard of protection of development sites, once built. In this way, while the Environment Agency may lag behind, the property, financial and insurance sectors can stay on top of the latest changes in flood risk mapping.

While awaiting brighter news concerning the flood map challenge process, I wish you all to stay safe (and please try building in Flood Zone 1 only!).

Want to know more?

For more information about this product, please email Olivier Saillofest.

Leave a Reply