Proposed flood mitigation improvements to facilitate the Leigh Flood Storage Area (FSA) expansion scheme. Improvements to Leigh and Cattle Arch embankments to include: partial raising of embankments; installation of 300mm high wave return wall; creation of pumping station platform area; erection of new fencing and gates and other associated works that include culvert, eel pass, temporary access and compound areas.

The proposal sought planning permission for flood mitigation improvements to facilitate the Leigh Flood Storage Area (FSA) expansion scheme. Improvements to Leigh and Cattle Arch embankments to include: partial raising of embankments; installation of 300mm high wave return wall; creation of pumping station platform area; erection of new fencing and gates and other associated works that include culvert, eel pass, temporary access and compound areas. The application had been referred to Development Control Committee as it was considered significant by the Deputy Chief Executive and Chief Planning & Regulatory Officer.

Members’ attention was brought to the main agenda.

The Committee was addressed by the following speakers:

Against the Application:              Kevin Storey

For the Application:                    Tim Connell

Parish Representative:                Leigh Parish Councillor Richard Britain

Local Member:                           -

Members asked questions of clarification from the speakers and officers which centred around the risk of flooding and use of the flood barrier and biodiversity works.  It was noted that increasing the maximum stored water level required a separate permission from the Secretary of State for Environment, Food and Rural Affairs, the Committee was only considering the impact of the flood mitigation engineering works required to facilitate the increased flood water storage, along with the impact of those works within the immediate vicinity and wider implications.  The application was to assist with increased flood water storage levels and flood modelling as shown in the application, demonstrated that the development would not increase the flood water depth level within Rogues Hill, Penshurst, nor would any residential property in Leigh be affected.

It was moved by the Chairman and duly seconded that the recommendations within the report, be agreed.

Members discussed the application.

          Resolved: That planning permission be granted subject to the following conditions:

 1)  The development hereby permitted shall be begun before the expiration of three years from the date of this permission.

In pursuance of section 91 of the Town and Country Planning Act 1990.

 2)  No works (including site clearance or preparation) shall commence on the development hereby permitted until final design and construction drawings and method statements in relation to works in the vicinity of the A21 Medway Bridge have been submitted to and approved in writing by the Local Planning Authority (who shall consult with Highways England). The construction of the development shall be carried out in accordance with the approved drawings and statements unless otherwise agreed in writing by the Local Planning Authority (who shall consult with Highways England). At the end of the construction period, a full set of as built drawings and associated documentation shall be provided to Highways England.

To ensure that the A21 Trunk Road continues to be an effective part of the national system of routes for through traffic in accordance with section 10 of the Highways Act 1980 and to satisfy the reasonable requirements of road safety.

 3)  If, during development, contamination not previously identified is found to be present at the site then no further development (unless otherwise agreed in writing with the local planning authority) shall be carried out until the developer has submitted a remediation strategy to the local planning authority detailing how this unsuspected contamination shall be dealt with and obtained written approval from the local planning authority. The remediation strategy shall be implemented as approved.

To reduce risk to controlled waters. There is always the potential for unexpected contamination to be identified during development groundworks and any contamination be identified that could present an unacceptable risk to Controlled Waters, in compliance with the National Planning Policy Framework.

 4)  Whilst the principles and installation of sustainable drainage schemes are to be encouraged, no infiltration of surface water drainage into the ground is permitted other than with the express written consent of the local planning authority, which may be given for those parts of the site where it has been demonstrated that there is no resultant unacceptable risk to controlled waters. The development shall be carried out in accordance with the approval details.

To ensure that the development does not contribute to, or is not put at unacceptable risk from, or adversely affected by, unacceptable levels of water pollution caused by remobilised contaminants present in shallow soils/made ground in line with paragraph 170 of the National Planning Policy Framework.

 5)  Prior to the commencement of the development hereby permitted, a Construction Environmental Management Plan (CEMP) shall be submitted for the written approval of the local planning authority.  The CEMP shall include, though not necessarily be limited to the following details: a) A Construction Traffic Management Plan incorporating details of heavy vehicles movement patterns, including earliest and latest arrival and departure times, routes to be used to and from the site and signs, information to instruct drivers and maintained at the applicant's expense throughout the construction period; b) The parking arrangements for vehicles of site operatives and visitors together with measures to reduce the daily number of trips to the site; c) The loading and unloading arrangements for heavy plant and materials; d) Processes of controlling/supressing dust emanating from the site; e) The location and type of temporary fencing/hoarding; f) The details of wheel cleaning facilities within the site to prevent mud being deposited on the public highway; g) The tool-box talk for the site operatives regarding protected species and awareness.

To mitigate the impact arising from development upon existing habitats of protected species on or surrounding the site and safeguard the amenities of adjacent neighbouring properties and existing road network in accordance with Policy SP11 of the Sevenoaks District Core Strategy, Policies GI1, EN1, T1 of the Sevenoaks Allocations and Development Management Plan and guidance in National Planning Policy Framework 2019.

 6)  Prior to commencement of works (including site clearance), a biodiversity enhancement plan will be submitted to, and approved by, the local planning authority. The plan will include a map of proposed enhancements, management prescriptions and biodiversity net-gain metric calculations. The approved details will be implemented and thereafter retained.

To ensure that the proposed development will not have a harmful impact on protected species and habitats, and make further wider biodiversity enhancements, in accordance with Policy SP11 of the Core Strategy and guidance in National Planning Policy Framework.

 7)  From the commencement of works (including site clearance), all mitigation measures for protected species and compensatory measures for habitats will be implemented in accordance with the details in section chapter 7 of the Environmental Statement (Environment Agency August 2020), unless varied by a European Protected Species licence subsequently issued by Natural England.

To ensure that the proposed development will not have a harmful impact on protected species and habitats, and wider biodiversity, in accordance with Policy SP11 of the Core Strategy and guidance in National Planning Policy Framework.

 8)  The increased capacity of the flood storage area up to 28.6mAOD shall not take place until the flood mitigation measures /Measures in the Interests of Safety measures as hereby permitted are fully completed and operational unless otherwise agreed in writing by the local planning authority.

In the interests of reducing flood risk prior to completion of the development in accordance with National Planning Policy Framework.

 9)  Notwithstanding the approved drawings, no steps will encroach onto the definitive line of Public Right of Way SR435.

For the avoidance of any doubt

10) The development shall be carried out in strict accordance with the Environmental Action Plan as found in Appendix A Environmental Statement dated August 2020.  Any changes to the Environmental Action Plan as hereby permitted shall be submitted to and agreed in writing by the Local Planning Authority.   The development shall accord with the approved and implemented in full.

To mitigate the impact arising from development upon existing habitats of protected species on or surrounding the site and safeguard the amenities of adjacent neighbouring properties and existing road/footpath network in accordance with Policy SP11 of the Sevenoaks District Core Strategy, Policies GI1, EN1, T1 of the Sevenoaks Allocations and Development Management Plan and guidance in National Planning Policy Framework 2019.

11) No demolition, site clearance or building operations shall commence on site until the protective fencing and other protection measures in the Arboricultural Impact Assessment dated 05/08/2020 have been installed. At all times until the completion of the development, such fencing and protection measures shall be retained as approved. Within all fenced areas, soil levels shall remain unaltered and the land kept free of vehicles, plant, materials and debris.

To protect the trees on site which are to be retained in the interests of the visual amenities of the locality in accordance with Policy EN1 of the Sevenoaks Allocations and Development Management Plan.

12) The development hereby permitted shall be carried out in accordance with the following approved plans:ENVIMSE100377-JBA-LZ-OO-DR-PL-1000, ENVIMSE100377-JBA-LZ-OO-DR-PL-1002, ENVIMSE100377-JBA-LZ-OO-DR-PL-1010, ENVIMSE100377-JBA-OO-ZZ-DR-PL-l000, ENVIMSE100377-JBA-OO-ZZ-DR-PL-l020, ENVIMSE100377-JBA-OO-CAOO-DR-PL-ll00, ENVIMSE100377-JBA-OO-CAOO-DR-PL-1204, ENVIMSE100377-JBA-OO-CAOO-DR-PL-1240, ENVIMSE100377-JBA-OO-CAOO-DR-PL-1241 ENVIMSE100377-JBA-OO-ZZ-DR-PL-1000, ENVIMSE100377-JBA-OO-MEOO-DR-PL-1303, ENVIMSE100377-JBA-OO-ME01-DR-PL-llOO, ENVIMSE100377-JBA-OO-ME02-DR-PL-llOO, ENVIMSE100377-JBA-00-ME03-DR-PL-1100, ENVIMSE100377-JBA-00-ME04-DR-PL-1100ENVIMSE100377-JBA-00-ME04-DR-PL-1101, ENVIMSE100377-JBA-00-ME04-DR-PL-1220, ENVIMSE100377-JBA-00-ME04-DR-PL-1225, ENVIMSE100377-JBA-00-ME04-DR-PL-1200, ENVIMSE100377-JBA-00-NR02-DR-PL-1100, ENVIMSE100377-JBA-00-NR02-DR-PL-1200ENVIMSE100377-JBA-00-EPOO-DR-EN-001, ENVIMSE100377-JBA-00-EPOO-DR-EN-002, ENVIMSE100377-JBA-DE-PFOO-DR-PL-1100 ENVIMSE100377-JBA-DE-PFOO-DR-PL-1101, ENVIMSE100377-JBA-DE-PFOO-DR-PL-1102, ENVIMSE100377-JBA-DE-PFOO-DR-PL-1103 ENVIMSE100377-JBA-DE-PFOO-DR-PL-1104, ENVIMSE100377-JBA-DE-PFOO-DR-PL-1105, ENVIMSE100377-JBA-DE-PFOO-DR-PL-1200-A5-C01, ENVIMSE100377-JBA-DE-PFOO-DR-PL-1201 to 1211, ENVIMSE100377-JBA-DE-PFOO-DR-PL-1301 & 1302 and Planning Design Access Statement, Arboricultural Impact_Assessment and Environmental Statement dated August 2020.

For the avoidance of doubt and in the interests of proper planning.

Informatives

 1)  The drawings and documentation required prior to and post construction should be produced in accordance with and demonstrate the compliance of the development with the Design Manual for Roads and Bridges, insofar as they apply to the A21 Medway Bridge and its vicinity. Drafts may be sent to planningse@highwaysengland.co.uk for agreement prior to formal submission to facilitate expeditious processing.

 2)  Fuel, Oil and Chemical Storage - Care should be taken during and after construction to ensure that all fuels, oils and any other potentially contaminating materials should be stored (for example in bunded areas secured from public access) so as to prevent accidental/unauthorised discharge to ground. The areas for storage should not drain to any surface water system.

Drainage - The following points should be noted wherever infiltration drainage (such as soakaways) are proposed at a site:

- Appropriate pollution prevention methods (such as trapped gullies or interceptors) should be used to prevent hydrocarbons draining to ground from roads, hardstandings and car parks. Clean uncontaminated roof water should drain directly to the system entering after any pollution prevention methods;

- No infiltration system should be sited in or allowed to discharge into land impacted by contamination or land previously identified as being contaminated;

- There must be no direct discharge to groundwater, a controlled water. An unsaturated zone must be maintained throughout the year between the base of the system and the water table;

- A series of shallow systems are preferable to systems such as deep bored soakaways, as deep bored soakaways can act as conduits for rapid transport of contaminants to groundwater.

Disposal of soil - Contaminated soil that is, or must be disposed of, is waste. Therefore, its handling, transport, treatment and disposal is subject to waste management legislation, which includes:

- Duty of Care Regulations 1991

- Hazardous Waste (England and Wales) Regulations 2005

- Environmental Permitting (England and Wales) Regulations 2010

- The Waste (England and Wales) Regulations 2011

Developers should ensure that all contaminated materials are adequately characterised both chemically and physically in line with British Standard BS EN 14899:2005 'Characterization of Waste - Sampling of Waste Materials - Framework for the Preparation and Application of a Sampling Plan' and that the permitting status of any proposed treatment or disposal activity is clear. If in doubt, the Environment

Agency should be contacted for advice at an early stage to avoid any delays. If the total quantity of waste material to be produced at or taken off site is hazardous waste and is 500kg or greater in any 12-month period, the developer will need to register with us as a hazardous waste producer.

Proposed ecological enhancement schemes -  Works such as Stage zero and river enhancements (Powdermill stream and Straight Mile) are likely to require an internal Flood Risk Activity Permit, which will assess impacts for flood risk, environmental and ecological concerns.

Any floodplain or riverine based mitigation/enhancement schemes will need to demonstrate that the activity will not cause detriment to Water Framework directive (WFD) status or protected species.

If delivered, the changes could also be included as an update within the Biodiversity Net Gain (BNG) calculations. The LPA may request to see an update if they wish.

Invasive Non Native Species (INNS) management plan approach and named references It is welcome to see a dedicated plan for identifying and managing the risk of potentially spreading INNS either around site, or through the activity (Le. spread elsewhere off site). There is specific example reference to Himalayan balsam and mudsnail species, which are locally detected and relevant risks to manage. However, it is recommended that the plan continues to also approach other high risk species, including American skunk cabbage (also reported within the area, but not listed on the legislation as Himalayan balsam - yet presents a credible risk to colonise wetland areas just as well) another approach is to direct a focus on the biosecurity protocols to control the most likely potential spread pathways of the most likely range of assumed species, i.e. rather than purely a prescriptive approach to specific species.

This is because the risk of spreading and introducing INNS are assumed to be ubiquitous, and the measures in place which affect the potential spread pathways will be appropriate for a range of species. Different taxa will also require different spread risk pathway analysis and biosecurity protocols.

Recommendation for INNS biosecurity protocols in site management documentation It is recommended to ensure biosecurity measures for each construction Area and phase is included within relevant Environmental Action Plan (EAP) and/or CEMP.

 3)  It is the responsibility of the applicant to ensure, before the development hereby approved is commenced, that all necessary highway approvals and consents where required are obtained and that the limits of highway boundary are clearly established in order to avoid any enforcement action being taken by the Highway Authority.

Across the county there are pieces of land next to private homes and gardens that do not look like roads or pavements but are actually part of the road. This is called 'highway land'. Some of this land is owned by The Kent County Council (KCC) whilst some are owned by third party owners. Irrespective of the ownership, this land may have 'highway rights' over the topsoil.

Information about how to clarify the highway boundary can be found at https://www.kent.gov.uk/roads-and-travel/what-we-look-after/highway-land/highway-boundary-enquiries

The applicant must also ensure that the details shown on the approved plans agree in every aspect with those approved under such legislation and common law. It is therefore important for the applicant to contact KCC Highways and Transportation to progress this aspect of the works prior to commencement on site.

 4)  Any changes or improvements to the public rights of way across the site will require the express consent of the Highway Authority, in this case KCC PROW and Access Service.

 5)  Southern Water Informatives

- The 450 mm public foul sewer and 450 mm public foul trunk sewer requires a clearance of 3.5 meters on either side of the sewers to protect it from construction works and to allow for future access for maintenance. No development or tree planting should be carried out within 3.5 meters of the external edge of the public sewer without consent from Southern Water.

- The 350 mm public foul rising main requires a clearance of 3 meters on either side of the sewers to protect it from construction works and to allow for future access for maintenance. No development or tree planting should be carried out within 3 meters of the external edge of the public foul rising main without consent from Southern Water.