Wilson Bowden Developments
Kingsway business park has a drainage system in place, with a sewer network adopted by United Utilities and several detention basins which were adopted by Rochdale Borough Council (the Lead Local Flood Authority), as part of the wider infrastructure within the business park.
The detention basins serve the entirety of the business park and the adopted sewer network was designed and adopted anticipating each individual plot to freely discharge to the wider drainage network up to the 1 in 100-year event, with on-plot flow restriction and attenuation for the climate change events above the 1 in 100-year event.
BWB was instructed to undertake an as-build-drainage-study of the existing adopted drainage networks and attenuation features using the historical information available and making assumptions based on current best practice where information was missing. The aim of the works is to inform the future drainage strategies for the various plots that are expected to come forward in the coming years.
BWB produced three separate drainage network models in MicroDrainage (one network model for each drainage catchment present within the business park). The MicroDrainage network model was produced using the available as-built drawings relating to the sewer network and the adopted detention basins and flow controls.
Following the modelling works, it was identified that one of the basins was 70% full of water the majority of the time, thus leading to the basin overtopping in certain rainfall events and causing minor flooding to surrounding paths and highways.