Appendix A (Version 1.1)

Doncaster MBC Supplementary Information to the South Yorkshire Interim Local Guidance for SuDS

Although the South Yorkshire Interim Local Guidanceis the minimum recommended standard to ensure a satisfactory scheme is constructed, there will be differences between each individual South Yorkshire Local Authority, with regards to what is acceptable, what will be adopted (if at all) and any commuted sums if applicable. This Appendix is supplementary to the Local Standards to provide further information and guidance to developers when submitting a Planning Application in Doncaster.

SuDS Design Statement

When submitting your Planning application and considering SuDS for your development (only applicable to Major applications as defined in Section 2) , it is expected (as a minimum) that you will have taken into account and provided the necessary information as follows:

  1. Considered hierarchically the drainage destination for surface water (section 6.3) and providing any options analysis for drainage solutions including discharge routes.
  2. Description and plan showing the characteristics of the site including topography, ground conditions and flood risk.
  3. How will the surface water drainage infrastructure (SuDS) be managed and by whom.
  4. Has consideration been given to the levels and layout of the site, as to how surface water (particularly exceedance flows) are managed both within and off site.
  5. Principles as to how storm return periods up to 1/100yrs plus climate change will be managed both on and off site.

Section 3 of the Local Standards also provides a check list as to the information required when submitting your planning application, but it is appreciated that the Flood Risk/Drainage strategy may not always be as fully developed at this stage, but it is expected that the information will be provided at some stage during the planning process for the development.

Note:-

If the Micro-Drainage software has been utilised for the design of the drainage system, then the Network file (.mdx file) is to be provided to the Local Planning Authority, for the purposes of ensuring the design meets the required criteria.

Highway Drainage Infrastructure

If infiltration (Soakaways orPermeable paving) is to be used to discharge the surface water run-off from a highway which is proposed to be adopted by the highway authority under a Section 38 agreement, it is expected that a commuted sum will apply to cover future costs relating to the inspection, maintenance and repair of that asset adopted by Doncaster MBC. Commuted sums will be calculated on a site specific basis, dependant of what type of drainage infrastructure Doncaster MBC will be adopting.

Typical commuted sum costs for the 3 types of drainage infrastructure we would adopt are as follows

Soakaway

£5k per soakaway. This is based upon a conventional pre-cast concrete ring soakaway, and this sum is subject to change for other types of soakaway (geo-cellular crates etc)

Permeable Paving

Doncaster MBC will consider adoption of permeable paving on a site specific basis, dependant on the typology and extent of the housing development associated with the highway to be adopted.

The commuted sum for permeable paving is based upon a maintenance period of 30yrs and calculated using the standard formula for calculating commuted sums.

Typical sum for a 300m2 area of permeable paving would be in the region of £7800

(This figure may be subject to review, once there is more certainty as to the definitive maintenance requirements for permeable paving)

By-Pass Separators (Oil/Petrol Interceptors)

These may be a requirement for some highway drainage systems, to protect the water quality and potential contamination of watercourses, aquifers etc.

Typically a figure of £5k per separator would be required.