Drainage
The latest 2025 Environment Agency flood maps have been used in the assessment of flood risk. Almost the entire site, and where built development is proposed, is located within Flood Zone 1, which is land at the lowest risk of fluvial flooding.
Some localised areas on site are at risk of a 1:1000 of surface water flooding. However, this risk will be mitigated post-development as the flooding is generated by rain falling on the site and will be removed by the introduction of an effective drainage system.
The development will discharge surface water to the existing watercourse to the south, mimicking the existing regime, with discharge restricted to the pre-development run-off rate to ensure that flood risk will not increase on-site or elsewhere.
Sustainable Drainage Systems (SuDS) will be incorporated to attenuate and store run-off for all rainfall events up to and including the 1 in 100-year event, including an allowance for climate change.
SuDS features will be carefully integrated into the landscaping proposals and include swales, basins and bio-retention areas, which offer good amenity value, ecological and bio-diversity benefits, and as act as effective pollution control.
Basins will be designed with shallow side slopes, low-flow channels and shelves to soften their appearance, and will be dry most of the time so they can be used safely as amenity space and avoid the need for them to be fenced.
Foul water will be discharged to an existing Thames Water sewer that crosses the site that will be diverted to suit the development layout. Thames Water has confirmed sufficient capacity for the development is currently available in the public sewerage system.
Ecology
The residential site comprises 23.32ha of buildings, hardstanding, vegetated garden, bramble scrub, lowland mixed deciduous woodland, native hedgerow, a pond and individual trees, including the SANG land.
To mitigate any potential impacts and deliver a minimum 10% on-site Biodiversity Net Gain, the following measures are being considered:
- Habitat enhancement of retained woodland to improve condition and ecological function
- Planting within areas of open space to strengthen habitat connectivity with retained woodland and other off-site woodlands
- Development of a Landscape and Ecological Management Plan (LEMP) and/or a Habitat Mitigation and Management Plan (HMMP) to formalise on-site mitigation measures
- Implementation of construction-phase safeguards, such as root protection zones, habitat protection fencing and pollution control measures, secured through a Construction Management Plan (CEMP)
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