DRAFT Sustainability Appraisal Report for the Emerging Local Plan ...

Receptor
Key Issues, challenges and potential responses for the Local
Plan
In February 2012 21,603 residential and commercial properties within the
borough were at risk of flooding.
Issues and Challenges: Urban development and supporting infrastructure
networks, such as those being proposed, and are likely to be enhanced as a
result of induced development. All of which can affect both the use and
quality of the water environment. The siting of urban development and
supporting infrastructure such as roads can interrupt the natural flows of both
surface and ground waters, and can add to problems on flood plains.
Common construction practice is to use piling which creates preferential
pathways for groundwater. The quality of both ground and surface water can
be affected by the run-off which is often laden with pollutants including fuel
oils and as well as seasonal road treatments (e.g. salt in the winter).
Possible LP Response: The LP could tighten the policies that it is bringing
forward policies to further minimise the risks of development and
infrastructure interfering with the water regime by not only avoiding
inappropriate development in flood plains but proactively encouraging
appropriate development and flood protection. Policies could also propose
that all developments incorporate systems to capture and filter surface water
run-off into the design of urban hard landscapes, roads and other supporting
infrastructure as appropriate.
How LP Responded: Policy SP10 looks specifically to address inappropriate
development in areas likely to flood. It confines itself to the standards as set
in the NPPF.
Evolution of Baseline in Absence of Plan
8.26 The projected impacts of climate change for the South East of England, coupled with a
growing population, would have a range of implications for the freshwater environment and
water resources. If average temperatures were to increase in the projected range, and
summers to become hotter and drier the region’s water resources and freshwater
environments would be placed at increased risk of adverse effect due to scarcity of resource
coinciding with a likely increase in demand from the population.
8.27 High demand in periods of hot weather coupled with restricted availability of surface water
supplies could also adversely affect groundwater and aquifers, the depletion of which would,
in turn adversely affect the base flows of rivers and streams. There have been several
hosepipe bans over the last few years to conserve water resources lasting from spring until
late summer.
8.28 In the event of the projected scenario of warmer and wetter winters being realised, the likely
surfeit of incident rainfall could result in a rise in the risks of flooding from fluvial sources and
non‐fluvial sources (i.e. surface water runoff during periods of heavy rain).
8.29 Whilst there is a cumulative effect potential on this receptor, the situation is unlikely to be
significantly affected by the absence of the plan alone. The ‘effect lock‐in’ of climate change,
means that the effects over the life of the plan, i.e. up to 2026 are already set.
Potential Impact Pathways
WRM1: Impacts on the flow of water
8.30 The physical provision of development and supporting infrastructure within Runnymede will
increase the risk of adverse effects as a result of changes to water flow through impedance or
acceleration of flow of generally surface water.
WRM2: Impacts on water quality
8.31 Pressure for development within Runnymede will increase the risk of adverse effects to water
quality through the development process and use of buildings
WRM3: Demand for water resources
Page | 114 Runnymede BC FINAL Sustainability Appraisal Report – Feb 2013