Sustainable Drainage for Housing Development

Bellway homes have created a name for themselves in medium to large scale housing developments, so when they approached us proposing 130 new builds in Buckinghamshire, we were keen to get stuck in. Our SOLID Bourne End crew analysed old site data that was presented, but in truth were hugely disappointed with the proposed. The initial drainage strategy depicted a plan that was in no way sustainable. With huge underground cellular storage to collect water from the proposed sports pitch area and oversized plastic pipes planned for water run off it was obvious that the design offered no longevity in terms of environmental impact.

SOLID Approach

The team got to work redesigning the drainage system to provide better sustainability, with SuDS at the forefront of their minds. SuDS omit the standard large scale, usually plastic, storage tanks. Instead, they work to redirect surface water through a network of channels to nearby watercourses. These watercourses usually provide ecosystems for neighbouring wildlife. We created a method that removed any residential risk, for example blockages or pump failures, which may have caused flooding at a later stage.

The new design replaced the enormous plastic storage tank with a series of swales and a detention basin, where water can discharge through gravity. By conducting tests in accordance with BRE 365 procedure we have ensured that infiltration is feasible and utilised the areas with highest infiltration rates. Where the detention basin discharges into existing ditches or attenuation ponds orifice plates are to be installed to restrict greenfield runoff rates.

Planning Gained

We were thrilled when our proposal gained planning approval immediately. The planners were so impressed with our design no challenges were presented or changes needed. The new drainage system will cut the cost dramatically, as no investment is required on large quantities of plastic piping or water storage systems. However, what is more important is the fact that we have enabled the site to adhere to sustainable drainage solutions, providing an eco-friendly long-term plan for the site.