Future developments and climate change are some of the key factors that are increasing the risk of flooding events across the UK and globally. Several key drivers, including urban development expansion, could see an increase in flood risk from various sources. For example, increased foul drainage from an increased local population places a greater pressure on the local sewer system. This has the potential to increase the risk of sewer flooding, especially in areas with combined sewers which drain foul and surface water. A decrease in permeable ground cover due to urban development may increase the risk of surface water and ordinary watercourse flooding.
The pressure of accommodating more developments may mean a larger number of developments being proposed for sites within higher risk Flood Zone areas, placing them at greater risk of flooding. The impact of development and projected future population growth may not only have an impact on the flood risk presented by different flood sources, but present a greater overall flood risk to people and properties due to the accumulative risk from each source. To meet flood risk mitigation requirements whilst facilitating housing development needs, local policy targeting the impact of future growth on flood risk is required.
The NPPF and accompanying PPG state that a sequential, risk-based approach to the location of development should be applied. This would enable possible flood risk to people and property to be avoided whilst taking impacts of climate change into account. This underpins the strategic recommendations for the borough and supports the site-specific recommendations. For further information, see Section 5.3.