RES Environmental Ltd were commissioned by Kirklees Borough Council to deliver a series of flood risk assessments, for a number of sites proposed for development across the Kirklees Borough.  A total of 12 sites were assessed.  A report for each site was created to outline the flood risk to the site and the drainage requirements within the site.

The assessments comprised of a number of elements to inform a future developer of hydraulic issues, including the following:  On site surface water storage requirements, based on limiting post-development run off rates to pre-development run over rates.  For this assessment MicroDrainage was utilised to calculate the runoff rates and the required storage volumes.  Two storage volumes were calculated based whether SuDS  were to be used or not used.

Flood risk maps for surface water flooding on the site were produced using InfoWorks ICM.  The maps were generated from EA LiDAR and soil maps, with a 2D mesh.  The output maps were designed to highlight any areas on the site with significant flood risk from over land flow and therefore not suitable for building properties or infrastructure.

A topographic assessment was carried out, based on EA LiDAR, using QGIS hydrology tools.  The assessment determined natural flow routes through the catchment, which the developments surface water drainage system should aim to emulate.  Optimum areas for SuDS features and large flood attenuation storage were also highlighted.

The report collated the findings and generated maps.  This information was contextualised, with the legal requirements and construction costs, to inform any potential developers of the drainage issues for the sites.