Concerns Regarding the Surface Water Drainage Design
May 11, 2020
Whilst reserve matters approval has been provided for this site, the development cannot commence until the planning conditions linked to it are discharged. Kedleston Voice has reviewed the plans regarding the Surface Water Drainage and believe that these have fundamental flaws within them. The planning conditions associated with the drainage must not be discharged as a consequence.
The issue of surface water drainage and the impact that this has on Markeaton Brook as well as the housing adjacent to and down stream of the development has grown in importance following the recent flooding of the Brook and water ingress into a number of properties. The National Planning Policy Framework is clear that any “development should be made safe for its lifetime without increasing flood risk elsewhere”. Residents have long argued that this cannot be delivered for the Kedleston Grange development.
From a detailed review of the Surface Water Drainage plans, Kedleston Voice are flagging several concerns to Amber Valley Borough Council, the Local Planning Authority, and Derbyshire County Council, its statutory consultee on these matters. The main concerns are:
The plans do not model the full surface water runoff from the site and, therefore, the attenuation ponds planned adjacent to the existing Somme Road development are not large enough. There is a risk of these overtopping in periods of heavy rainfall.
The flow of surface water to one of these ponds is required to cross an existing water main which appears to block its path. No explanation as to how this will be resolved has been included within the plans.
The flow of water from the two attenuation ponds then needs to find its way to the Markeaton Brook for full discharge. At present, the development site has no access to the Brook and so it is not clear how this will be achieved.
The flow rates into the Brook must be no more than the discharge rates seen from the existing fields. Previously, this has led to water ingress into the Somme Road development and are likely to have contributed to flooding issues on Somme and Ypres Road. The designs presented give no confidence that flood risk will be improved or even maintained when this development is built.
All this is compounded by the changing nature of the rainfall being seen within the United Kingdom and the increased flooding that this is causing. Whilst the planning guidance has failed to keep up with these changes, Kedleston Voice believes that this proposed development, as designed, cannot be made safe for its lifetime without there being an increased flood risk elsewhere.
If you would like to share your concerns regarding the flood risk presented by this development and the inadequate surface water drainage solution submitted whilst the application to discharge the drainage condition is being considered, please write to: