Southern Water strongly supports the inclusion of sustainable design principles within planning policy. For the reasons explained further below, we ask for additional planning policy wording to protect natural flow routes and site drainage features.

Requested changes:
• A(i) Landscape Strategy. … All layout or landscape units..and information about surface water flows. Existing flow routes and drainage features within the site should be identified and preserved wherever these contribute to sustainable drainage eg ditches, seasonally dry watercourses, historic ponds…

Further explanation and justification:
Southern Water supports all policy requirements which seek to ensure that surface water is appropriately managed, as close to source as possible. We need planning policy to consider carefully the measures called for in response to the climate crisis, and ensure sustainable development is central to the local planning framework for planning applications coming forward. This is also in line with the requirements of paragraph 167(c) of the NPPF (2023). Measures should support the attenuation of flows of surface water run-off from rainfall, as well as surface water infiltration into the ground wherever possible in the local environment. Please see our policy statement on Sustainable Development here:
https://www.southernwater.co.uk/media/ny0nb3qu/our-policy-statement-on-sustainable-development-a4.pdf

Southern Water is working across our region to remove surface water from our networks in key areas. Even as we deliver this work, development continues to increase surface water run-off. To be resilient to the evolving impacts of climate change we must plan to ensure that rainwater is separated from wastewater in the design and construction of our communities. For more information on our work, and the root causes of releases from storm overflows, please see –
https://www.southernwater.co.uk/our-region/clean-rivers-and-seas-task-force/pathfinders/
https://www.southernwater.co.uk/our-performance/storm-overflows/storm-overflow-task-force

During heavy rain, local sewer networks’ drainage capability can be exceeded by the amount of rainwater entering pipes and storage tanks connected via roads, roofs and paved areas. When these fill up, storm overflows release excess water through outfalls into rivers and the sea to prevent flooding of homes and businesses. Storm overflows are part of the network’s original design and are regulated by the Environment Agency. Over time, the expansion of urban settlements as well as ‘urban creep’ (home extensions, conservatories and paving over front gardens for parking) have incrementally added to the amount of rainwater entering sewers, resulting in increased releases from storm overflows. As stated in Water UK’s 21st Century Drainage Programme;
“The country’s built environment is constantly changing and “urban creep” – home extensions, conservatories and paving over front gardens for parking – can all add to the amount of water going into our sewers and drains. Green spaces that would absorb rainwater are covered over by concrete and tarmac that will not. In fact, studies show that “urban creep” results in a larger increase in predicted flooding than new housing, because it adds more rainwater to these systems’.
In terms of future flood risk, better rainwater management through SuDS is the preferred approach to avoid placing added pressure on drainage networks during heavy rainfall. Retrofitting sustainable drainage solutions can be challenging. By showing the way with new development we can reduce the implementation costs of these measures whilst securing truly sustainable development.

Please see attached comments from Burwash Parish Council.

Please see attached document for the full submission from Westfield Parish Council.

Please see attachment