Flooding, drainage and coastal protection

As part of the Council’s Planning Role The Council's statutory duties as Flooding Authority and as Coast Protection Authority are carried out by the Planning Service and include:

• Commenting on Flooding and Drainage matters associated with current Planning Applications
• Commenting on Flooding and Drainage matters associated with potential development sites assessed for inclusion in the Local Development Plan.

Suitable consideration of drainage and flood risk is required under local and national planning policies and also makes sure that a flood risk is not created to the new development or neighbours. The general requirements for flood risk and drainage design issues for the Local Development Plan, and for individual planning applications are based on:

Surface Water drainage to include SUDs devices:

• Selected and designed in accordance with Ciria C753 “The SUDs Manual” guidance
• Providing attenuation of 1 in 10 year rainfall events to greenfield flows
• Providing water quality treatment to C753
• Ensuring no flood risk to property or public infrastructure during up to 1 in 200 year events

Coastal flood risk assessed on:

• 1 in 200 year still water tidal projections
• Plus a freeboard allowance
• Plus current SEPA climate change allowance for sea level rise

River flood risk assessed on:

• 1 in 200 year flood risk
• Suitable accommodation of “Burn Buffers”
• Engineering works meeting SEPA CAR licencing requirements

Further information and details on the above issues are covered in the SIC draft supplementary guidance documents:

• Water and Drainage
• Water and drainage - technical appendix

Which also include links to more detailed information provided by SEPA and other 3rd parties.

For the large majority of proposals a suitable layout will be possible to meet the requirements and make for a safe and easy to maintain development, but in many cases this can be easier to achieve if the aims and issues are understood early enough in the design process to make drainage design easier to fit into the site layout.
We are happy to discuss potential issues before design begins, or to give informal comment on draft plans before a planning submission, to try and support good design.

Contact
Colin Smith
Planning Engineer
Shetland Islands Council
8 North Ness Business Park
Lerwick
Shetland
ZE1 0LZ

Email: Planning.Flooding.Drainage.Coastal@shetland.gov.uk
Tel: +44 (01595) 744881