The 500 acre “Newlands” residential development at Berewood, Hampshire, is the largest of its type in the UK and, once completed, will accommodate over 2,500 homes, supported by a range of amenities and around 100,000m² of employment land.
Commissioned by Grainger plc and Hampshire County Council, Berewood is a mixed-use development. Their brief was to integrate best-in-class, below ground hard-engineered Sustainable Urban Drainage Systems with above ground vegetative SuDS amenities.
Overview
Construction of the development began in 2012 and continued until 2021. The project’s main surface water management objective was to minimise the site’s impact on its natural surroundings and deliver ecological benefit to the locality, providing both pollution and flood prevention services while creating a new wetland resource of substantial ecological and amenity value.
What they did
SDS worked closely with Consulting Engineers, Mayer Brown, to establish the key design criteria for the site’s sustainable drainage systems. This resulted in the adoption of a “SuDS management train” approach, whereby a series of drainage techniques are used to change the flow and quality characteristics of the runoff in stages. Surface water runoff from the roads and the housing development construction site is first cleaned through ditches and swales, before entering SDS’s purpose-built attenuation tanks, along with the water received from numerous water features.
Phases of consented land were released to housebuilders only after the supporting infrastructure had been installed, for which SuDS were considered a priority. As each phase was launched, further SuDS were installed, with developers integrating the existing surface water drainage scheme into each of the housing and commercial packages.
Results
To accommodate the unique complexities of the site that are associated with a clay dominated soil, including a very high water table, SDS designed and engineered a pioneering method of installation.
As specified by SDS, the hard-engineered features of the scheme were capable of performing their role of controlling water quality and volume, not only upon final completion of the development, but also during its 10-year period of construction.
This is before the natural SuDS elements can be fully established, and with a substantially higher level of water-bound contaminants than might normally be expected. Water leaving the SuDS system has been test proven to be of a higher quality than the contents of the watercourse into which it was being discharged.
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Similar projects by SDS include Blackpool Hospital. where attenuation tanks were installed to support flow control.