The proposal included construction of 103 dwellings (including 36 affordable units) with associated playspace, sustainable urban drainage systems, access to green lane via a new junction, landscaping including woodland and tree planting and enhancement to wildlife habitats.
The site is currently greenfield, agricultural land used for grazing which is split with hedgerows and mature trees. The existing topography of the site was steep with some areas reaching 1:3 as it banks down towards the existing boundary retaining wall or highway.
The works carried out by CampbellReith included a full civils detailed planning design constituting of a drainage report, drainage design, levels design, earthworks cut and fill assessment and S278.
There is an existing retaining wall that acts as a boundary between the site and existing road which the site would tie into. The road is approximately 2-3m lower than the existing onsite levels. This posed a challenge in ensuring that the road levels tied into the existing road while trying to minimise the cut and fill requirements for the site. In order to overcome this challenge, the road was designed to incorporate the maximum allowable gradient within East Sussex County Council guidance (1:12), allowing the road level to catch up to the existing onsite levels. The stretch of steeper road helped to reduce the level of cut material generated whilst also allowing part M compliant front site accesses to be retained.
The northern eastern corner of the site was a localised low area. Levels in this area had to be reviewed as pumping may have been a requirement to discharge foul and surface water. The need for pumping was removed by raising levels using the excess material from the cut and fill analysis.
Surface water runoff from the site is to be discharged into an existing offsite watercourse, therefore, to ensure the water quality runoff from the site had to be adequately treated. In order to achieve a suitable level of surface water treatment, multiple SuDS features were implemented on the scheme including attenuation basins, permeable paving, swales, petrol intercepts and granular drains.