Decision details

RESOLVED: That application 20/02779/FP be GRANTED planning permission subject to the reasons and conditions outlined in the report of the Development and Conservation Manager and the following amendments and additions to conditions:

·         Indexation for Herts County Council S106 payments is PUBSEC 175.

·         Condition 6 be amended to the following:

“Prior to the occupation of the development hereby permitted the principal access road shall be provided 5.5 metres wide with the side access road being 4.8 metres wide  to provide localised widening where possible up to 6.0m without encroaching onto plots 17, 18 and 19. All exiting footways are to include tactiles and dropped kerbs at crossing points and links to footways on the new development, thereafter the access roads and footways shall be retained at the position shown on the approved site layout plan number BEV-537-PA-001 Rev E. Arrangements shall be made for surface water drainage to be intercepted and disposed of separately so that it does not discharge from or onto the highway carriageway.

Reason: To ensure satisfactory access into the site and avoid carriage of extraneous material or surface water from or onto the highway in accordance with Policy 5 of Hertfordshire’s Local Transport Plan.”

·         Condition 16 to be amended to the following:

“The development permitted by this planning permission shall be carried out carried out in accordance with LLFA consultation letter dated 15 September 2021 prepared by EAS with attachments A-E (Appendix A proposed site layout plan BEV-357-PS-001-Rev E) prepared by MS Square Architect Ltd. Appendix B proposed drainage layout 2822 SK01 Rev D dated 14 September 2021, appendix C Source Control Calculations dated 15 September 2021, Appendix D Micro drainage calculations dated 15 September 2021, appendix E Exceedance Routes 2822 SK05 dated 15 September 2021 all prepared by EAS and the following mitigation measures:

1.    Provide minimum attenuation of 162.8 cubic metres and infiltration 262.6 cubic metres to ensure no increase in surface water run off volumes for all rainfall events up to and including the 1 in 100 year + climate change (40%) event.

2.    Implement drainage strategy based private soakaways, permeable paving with sub-base on all roads, mews and parking areas, oversized pipe, geocellular attenuation tanks and a restricted discharge at 2.5I/s at MH44 and 2.9I/s at MH14 via a Hydro brake into the Thames water foul water sewer.

Reason: To prevent flooding by ensuring the satisfactory storage/disposal of surface water from the site.”

·         Condition 17 to be added as follows:

“No development shall take place until the final design of the drainage scheme is completed and sent to the LPA for written approval. All approved drainage details shall be carried out carried out in accordance with LLFA consultation letter dated 15 September 2021 prepared by EAS with attachments A-E (Appendix A proposed site layout plan BEV-357-PS-001-Rev E) prepared by MS Square Architect Ltd. Appendix B proposed drainage layout 2822 SK01 Rev D dated 14 September 2021, appendix C Source Control Calculations dated 15 September 2021, Appendix D Micro drainage calculations dated 15 September 2021, appendix E Exceedance Routes 2822 SK05 dated 15 September 2021 all prepared by EAS. The scheme shall also include:

1.    Detailed engineering drawings of the proposed SUDs features including their location, size, depth and any inlet and outlet features including any connecting pipe runs and all corresponding calculations/modelling to ensure the scheme caters for all rainfall events up to and including the 1 in 100 year +40% for climate change event.

2.    Detailed engineering drawings of the access road arrangements between the permeable paving and sub-base and oversized pipe, including the connecting pipe from MH14 into the Thames Water foul sewer and how surface will be captured from the surface water of the road and the entrance of the site where MH14 is located.

3.    BRE digest infiltration tests in the location of the proposed private soakaways and permeable paving areas including an assessment of seasonal variation to ensure the infiltration of surface water can be catered for effectively during the Autumn and Winter months for all rainfall events up to and including the 1 in 100 year + climate change event.

4.    Demonstrate appropriate SUDs management and treatment and inclusion of above ground features such as permeable paving, reducing the requirement for underground storage.

5.    Provision of half drain downtimes for surface water drainage within 24 hours.

6.    Silt traps for protection for any residual tanked elements.

Reason: To prevent flooding by ensuring satisfactory storage and disposal of surface water from the site.”

·         Condition 18 to be added as follows:

“Upon completion of the drainage works for the site in accordance with timing / phasing arrangements, the following must be submitted to and approved in writing by the Local Planning Authority.

1.    Provision of a verification report (appended with substantiating evidence demonstrating the approved construction details and specifications have been implemented in accordance with the surface water drainage scheme). The verification report shall include photographs of excavations and soil profile/horizons, installation of any surface water structure (during construction and final make up) and the control mechanism.

2.    Provision of a complete set of a as built drawings for site drainage.

3.    A management and maintenance plan for SUDs features and drainage network.

4.    Arrangement for adoption and any other measures to secure the operation of the scheme throughout its lifespan.

Reason: To prevent flooding by ensuring satisfactory storage and disposal of surface water from the site.”