Hydrology

Site hydrology

We know that residents have been concerned about the hydrology of the site and how this may be impacted by a new development. Every site has unique drainage characteristics, as a result of the interaction between factors such as existing watercourses, geology, soil, slope and surface materials for example. We have carefully considered these factors to enable us to develop a site-specific approach to drainage at Englishcombe Lane, which recognises and responds to the site’s special characteristics. This involves a number of steps, as shown in the flowchart.

Drainage Strategy for the Site

Sustainable Drainage Systems (SuDS) are water sensitive drainage systems which mimic natural catchment processes to manage runoff. Our approach emulates the natural drainage of the site as closely as is practically achievable. in accordance with good practice. The proposed SuDS Strategy incorporates:

• Green roofs on all dwellings to help reduce surface runoff
• The use of small scale raingardens to the front of dwellings
• Water butts at the rear of each dwelling to provide an element of rainwater capture and re-use
• Geo-cellular attenuation tanks will be used to create a below-ground void space for the temporary storage of surface water prior to infiltration, controlled release, or use
• Permeable paving (allowing rainwater to infiltrate through the surface and into the underlying structural layers) along the access road
• Two separate vortex flow control devices are proposed upstream of the proposed outfalls to the adjacent watercourse.

Drainage strategy - click to enlarge