Central Bedfordshire Pre-submission Local Plan (January 2018)
16.1.1 This section sets out the planning policies that will be applied to ensure that development in Central Bedfordshire is delivered in a way that contributes to the mitigation of climate change and embeds adaptation to the impacts of climate change in order to limit negative impacts.
16.1.2 The NPPF stresses that responding to challenges of climate changes is central to the economic, social and environmental dimensions of sustainable development, placing an emphasis on Local Planning Authorities to adopt proactive strategies to mitigate and adapt to climate change in line with provisions and objectives of the Climate Change Act (2008).
16.1.3 As with the Environmental Enhancement Section, this section/chapter is underpinned by the Council's Environmental Framework. This document summarises a range of local studies, assessments, strategies and guidance, and forms part of the technical evidence base for the Local Plan and is the supporting document for these policies.
Climate change mitigation: Cutting the carbon footprint of new development
16.2.1 The Climate Change Act (2008) establishes a legally binding target to reduce the UK's greenhouse emissions by at least 80% in 2050 from 1990 levels.
16.2.2 The Government's expectation set through the NPPF is that each local authority contributes to meeting this target through setting local requirements for the sustainability of buildings that are consistent with the Government's zero carbon policy, adopt nationally described standards, and promote energy from renewable and low carbon sources.
16.2.3 The Council recognises the benefits of using the energy hierarchy in reducing energy demand and a fabric first approach, along with use of passive solar design is recommended before deciding on appropriate renewable and low carbon technologies.
16.2.4 As such, the Council will require all major developments to submit a Sustainability Statement that clearly demonstrates the steps that will be taken to minimise the lifetime carbon emissions resulting from the development. This could focus cutting carbon emission by reducing energy demand through taking a 'fabric first' approach to building or the implementation of building or development based renewable and low carbon technologies. The aim will ultimately be to reduce the impact of the proposed development by at least 10%. This will be measured through energy consumption, with the baseline for this calculation being the energy demand of a scheme compliant with Part L of the Building Regulations that are applicable at the time of the application.
16.2.5 The Sustainability Statement will also set the strategy to address widely recognised issue of buildings not performing as designed (identified by Zero Carbon Hub as the performance gap), by confirming the proposed measures to ensure that new buildings achieve the energy performance intended at the design stage.
16.2.6 Climate change adaptation: Water efficiency; flood resilience, subsidence and overheating
16.2.7 Climate change projections show that we will experience hotter drier summers, milder winters, and the associated extreme weather impacts of drought and flooding.
16.2.8 In 2017 the UK Climate Change Risk Assessment highlighted the need to take early action to mitigate the risks to the environment, the economy and to health, and to ensure that the UK can adapt to the changing climate.
16.2.9 The Central Bedfordshire Local Climate change Risk Assessment (LCCRA) identifies flooding, overheating, water resources shortages, subsidence and impacts on the natural environment as risks that need to be planned for and managed. These correspond with the 2017 National Climate Change Risk Assessment as priority areas for actions.
16.2.10 Adaptation to climate change is a dynamic and flexible process, with decisions that are made in the near term needing to have regard of the long lifespan of buildings and infrastructure. This includes exploiting opportunities to adapt existing built areas, for example through maximising green infrastructure or by increasing the amount of urban greenery to help absorb floodwater and make buildings and open spaces more comfortable in hot weather. Projected climate changes and their impacts should be taken into account and all developments should be designed to the current best estimate of future impacts, or where demonstrated as not practicable, development design should allow retrofit of adaptation measures, for example fitting of brise soleil to prevent overheating.
Making development resilient to the impacts of increased rainfall and drought
16.2.11 The design of new developments should reflect the increasing likelihood of periods of either drought or flooding, and consequently value water as a resource that can be stored in times of plenty for re-use in times of deficit. All new developments will therefore be expected to address the issue of water scarcity.
16.2.12 Consequently, all new development will be expected to achieve the higher water efficiency standard of 110 litres per person per day, as set by the Part G of the Building Regulations. All commercial development will be expected to demonstrate how water usage will be reduced and the equivalent of the BREEAM 'very good' standard for water efficiency achieved. Developments that will achieve high water efficiency standards going beyond the Building Regulations requirements and those that will include water harvesting and recycling will be looked at favourably. Measures that further promote water efficiency and aim at achieving water neutrality, such as grey water recycling and water butts, will be considered favourably.
16.2.13 Site scale adaptation measures, such as Sustainable Drainage systems are dealt with in Policy CC1, however on the individual building level, new developments are required to use simple rainwater harvesting (for example through provision of water butts, for external use wherever practicable.
16.2.14 Flood risk at a site level is dealt with in Policy CC3, but it is important that where appropriate, buildings are designed to be resistant or resilient to flooding and the impacts of flooding both now and in the future.
Mitigating overheating and the urban heat island
16.2.15 Built up areas with minimal open green space may exacerbate the risks associated with the urban heat island effect, where heat absorbed by heavy man-made structures radiates at night increasing local temperatures. This risk can be minimised by increasing green space, use of solar reflective materials and coatings as well as designing ventilation paths through which hot air can be replaced with cooler air from nearby green open spaces. Providing more natural drainage systems to enhance water surfaces in urban areas also has a greater cooling effect, whereas temperatures are higher in densely developed areas with little green space around them.
16.2.16 The orientation of a building together with a proportion and positioning of glazing areas determine the level of transmitted solar gain. This is particularly important where solar gain cannot be absorbed (for example by thermal mass) or extracted (through purge of mechanical ventilation) internal temperatures will increase.
16.2.17 If managed properly, solar gain can be beneficial in reducing energy demand for heating, but equally it needs to be controlled to avoid build up of unwanted heat leading to overheating. This can be controlled through careful orientation of the building and integration of effective solar control measures, such as brise soleil, external shutters, solar control glazing into a building and tree planting into landscape design.
Managing risks through good design
16.2.18 The Sustainability Statement, to be submitted with applications for all major developments, will also demonstrate how the above climate change risks will be addressed through design, and will set out the strategy to minimise and manage these risks through the lifetime of the development.
16.2.19 Good design can improve the quality of places and ensure they are adapted to a changing climate. Integrating green space and water within developments can provide many benefits for climate change adaptation including flood storage, localised climate cooling and habitat creation. Developers should make use of the Council's Design Guide, which includes information on how to consider resource efficiency and climate change adaptation in the design of developments.
Supporting the use of sustainability standards for development
16.2.20 There are a number of well recognised standards for built environment for both residential and non-residential developments, such as BREEAM, PassivHaus and the Home Quality Mark. The PassivHaus standard concentrates on energy efficiency, thermal comfort and indoor air quality while home Quality Mark and BREEAM covers much wider range of issues that affect sustainability of the development.
16.2.21 The Council will look favourably at proposals that use these standards to demonstrate their sustainability and achieve higher standards than those prescribed by the Building Regulations demonstrated by certification of relevant scheme.
16.2.22 All major developments will be required to submit a post construction verification report to confirm that the development has been delivered to the approved specification. The report should provide validation documents covering all aspects of the policy and provide as delivered evidence of compliance, for example as built energy calculations, BREEAM or PassivHaus certification, photographic evidence of implemented landscape or green infrastructure specification.
In order to ensure the delivery of high quality sustainable development, where appropriate, proposals must demonstrate how they support the mitigation of, and adaptation to, the impacts of climate change.
The Council requires that any new development is designed to increase its own resilience and the resilience of the surrounding area within the site to climate change. This will be demonstrated through the submission and preparation of an adaptation strategy which will detail the measures that will be taken in order to minimise the developments vulnerability to the impacts of climate change. This will include:
- Minimising the risk of overheating through good design and site layout, and making use of green roofs and walls, shading, landscaping and planting as appropriate.
- Where there is the potential for flood risk the sequential approach will be taken, with mitigation measures and integration of building level flood resistance and resilience measures provided as appropriate, allowing for climate change.
New development will be required to incorporate measures that minimise and mitigate its impacts on the environment and climate change by:
- Reducing carbon dioxide emissions
- Maximising energy efficiency and conservation through orientation, layout and design of buildings, landscaping and planting,
- Making use of natural lighting and beneficial solar gain,
- Taking advantage of opportunities to use renewable and low carbon energy sources,
- Minimising water usage and is delivered to the higher water efficiency standard (110 litres per person per day) for residential development and the BREEAM 'very good' standards for water efficiency for commercial development, and demonstrates a water sensitive approach to the design in all developments.
- Incorporating measures that further promote water efficiency and aim at achieving water neutrality, such as grey water recycling or water butts will be considered favourably.
All major developments must provide a Sustainability Statement. This will demonstrate:
- How the above requirements relating to all new developments will be met.
- That the development will provide for a minimum of 10% of its energy demand, using the energy demand for a scheme compliant with Part L of the Building Regulations applicable at the time of application as the baseline) to either be reduced through a fabric first approach, deployment of energy efficient technology, offset from site or building located renewable and low carbon energy sources, or by whatever means are appropriate.
- How the performance gap between built and designed energy use will be negated.
- Incorporate an adaption strategy that considers, how good site design and layout, hard and soft landscaping (trees, vegetation, green walls and roofs) and amenity space will support adaptation to the impacts of climate change, and are also designed to achieve visual, acoustic, wildlife and other environmental benefits.
The Council will support developments that can demonstrate
high quality sustainability standards going beyond the
Building Regulations requirements and achieve certification
to voluntary standards such as PassivHaus, BREEAM
Excellent, or the Home Quality Mark.
16.3.1 The Council recognises the importance of increasing the amount of energy generated from renewable and low carbon technologies, as well as supporting the evolving sustainable energy infrastructure that collectively will ensure that the UK has a secure energy supply, reduces greenhouse gas emissions to slow down climate change, and stimulates investment in new jobs and businesses.
16.3.2 The Council is taking a positive and technology neutral approach to planning for renewable and low carbon energy generation and sustainable energy infrastructure, with the basic premise being that the most appropriate technology is deployed in the most appropriate location. The Renewables Capacity Study for Central Bedfordshire (March 2014) shows that a range of technologies may be suitable for this area and are effectively placed to deliver maximum local benefits, whilst at the same time contributing to the national need to increase low carbon energy generation. These include, but are not limited to, district heating schemes, photovoltaic energy, wind, locally sourced biomass and utilisation of landfill gas.
16.3.3 The Council also recognises that the energy market is rapidly evolving and it is expected that new technologies and infrastructure will emerge throughout the lifetime of this policy. For example, since the Renewable Capacity Study was completed there have been significant advances in Battery Storage and smart metering.
16.3.4 Because of the importance of the transition to a decentralised renewable and low carbon energy system for the UK, the Council will be positive in its support for applications that relate to energy technologies and infrastructure as long as they are compliant with national energy policy, have no unacceptable adverse impacts that cannot be mitigated and will benefit local communities. In particular, community energy projects and those that have community backing are encouraged and will be supported by the Council.
16.3.5 The strategic allocation of sites set out in this plan presents significant opportunities for the provision of such infrastructure due to the potential for a concentration of significant demand in a single location, along with the fact that they can be integrated into the development at the initial design stage. It is recognised that applications are likely to include a portfolio of technologies that complement each other, for example generation technologies, storage and distribution infrastructure, and be co-located on one site with both residential and non-residential uses.
16.3.6 The Written Ministerial Statement (June 2015) states that the Local Plan should identify 'areas as suitable' for wind energy development. What constitutes a 'suitable area' (as opposed to a defined site) is based on a range of factors, including landscape character and ability to accommodate wind development, proximity to existing and future urban areas and infrastructure, grid capacity, radar and sensitive locations (such as historic buildings and sites and ecologically sensitive areas). How this is interpreted in Central Bedfordshire is set out in the Council's existing technical guidance notes for renewable energy, which has greater scope to take into account the latest information.
16.3.7 In addition to this, the role of positive community engagement is key. It is a fundamental requirement that developers engage with affected communities and stakeholders at the earliest opportunity, listen to their concerns and are able to demonstrate how these issues will be addressed. Guidance on community engagement is also detailed in the Council's technical guidance for wind.
Policy CC2: Sustainable energy development
The Council recognises the environmental, social and economic benefits of renewable or low-carbon energy and sustainable energy infrastructure.
The Council will positively support energy developments which:
- Are located in the suitable areas where negative impacts can be most effectively mitigated through design, scale and sitting of the project;
- Are located and designed so as to have no unacceptable adverse impacts on heritage assets, sensitive landscapes and townscapes, noise, pollution and harm to visual amenity;
- Can demonstrate engagement with affected stakeholders, including communities, in order to understand and address issues for objection;
- Can provide environmental benefits and is supported by local communities.
Wind energy development
In case of wind farm developments, the Council will support the principle of those that can demonstrate that they:
- Are located in areas identified as suitable for wind development by the Council's Wind Farm Development Technical Guidance;
- Demonstrate that following consultation, the planning impacts identified by affected local communities have been fully addressed and therefore the proposal has their backing.
Solar farm developments
In case of ground mounted solar PV farms, the Council will support the principle of those developments that can demonstrate that they:
- Avoid locations with best and most versatile land or can demonstrate the most compelling evidence to justify the location
- Are delivered in accordance with the Council's Solar
Farm Development Technical Guidance
16.4.1 Central Bedfordshire has been subject to flooding from several sources of flood risk, with the principal risk from fluvial sources, primarily located along the River Ivel corridor in the east, River Flit and River Hit in the centre and Clipstone Brook through Leighton Buzzard in the west.
16.4.2 The area has experienced a number of historic surface water and drainage related flood events caused by factors such as insufficient storm and combined drainage capacity to poor surface water management. The SFRA and the Environment Agency's updated Flood Map for Surface Water (uFMfSW) mapping shows a number of prominent overland flow routes, following topographical flow paths of existing watercourses or dry valleys and local road infrastructure with some isolated ponding located in low-lying areas.
16.4.3 Incidents of historic groundwater flooding in Central Bedfordshire are thought to mostly be caused by the underlying geology of chalk and Lower Greensand, which allows water to pass to and from groundwater aquifers.
16.4.4 The likelihood and impact of flooding is expected to increase in the future due to the impacts of climate change and all new development must take this into account. This can be done through using the appropriate allowances for peak river flows and rainfall intensities when determining risk to the site and the design of flood mitigation and drainage. Likewise, new development will need to ensure people and property will remain safe from flooding for its lifetime. Proposed flood mitigation and drainage infrastructure must be designed to handle intense or extreme storm events as well as residual risks associated with exceedance or system failure, taking into account climate change projections.
16.4.5 To minimise the risk created to people and property from new development the NPPF instructs Local Planning Authorities to direct development towards areas at the lowest risk of flooding, develop policies to manage flood risk from all sources, and take opportunities offered by new development to reduce the causes and impacts of flooding.
16.4.6 The suitability of development will be assessed by applying the Sequential Test. If, having passed the sequential test, development is proposed in areas at risk of flooding (from all sources) then developers will be required to complete an Exception Test, and demonstrate that suitable compensatory storage and mitigation can be provided, and that the development will result in an overall reduction of flood risk on site and elsewhere. Proposals for development in areas at high risk of flooding from all sources will be refused if other suitable sites are reasonably available in areas at lower risk.
16.4.7 A sequential approach to the layout of development should be taken at the site level and all development proposals must take account of existing and future flood risk (from all sources). They must demonstrate that the development will be appropriately flood resilient and resistant, safe for all of its users for the lifetime of the development, and that it will not increase flood risk overall. Developers will be expected to enhance green infrastructure and reduce flood risk by making space for water, avoiding, or (where unavoidable) compensating for any loss of flood storage or flow routes, and demonstrating sustainable drainage.
16.4.8 To minimise the risk from surface water runoff all new development are expected to minimise areas of hardstanding and maximise the use of porous or permeable surface for infiltration, treatment and storage; for example by using permeable paving. Sustainable drainage (SuDS) should be used on all new development as detailed through Policy CC5.
16.4.9 Development should take account of, and be consistent with the Council's SFRA (or more up to date equivalent if applicable), the Catchment Flood Management Plan, and further material on national policy and local information on flood risk. This may include information from the Environment Agency, Internal Drainage Board, Local Authority, or other local knowledge. This information should be used to inform the masterplanning of major development sites, and any sites where a site specific assessment of flood risk is required.
16.4.10 In addition to the criteria set out in the NPPF, the Council will require a site specific assessment of flood risk for new development within 20m of any watercourse (including those not shown on the Environment Agency Flood Maps), the Council's Strategic Flood Risk Assessment (SFRA), or within an area where are significant surface water issues. This should include an assessment of the existing drainage system, and all flood risks affecting the site.
16.4.11 The Local Planning Authority (LPA), Environment Agency, Internal Drainage Board, and Lead Local Flood Authority (LLFA) should be consulted to confirm the level of assessment required and to provide any information on any known local issues.
16.4.12 In areas identified at high risk by the SFRA, the Local Flood Risk Management Strategy (2014) or the Climate Change Adaptation Evidence Base Report (2012) the Council may specify requirements for mitigation measures such as controlling surface water run off to below the pre-developed rate.
16.4.13 Development with the potential to impede or displace floodwaters will be required to demonstrate the proposal will not increase flood risk on or off the site. Flood compensation may be required by the council to manage flood levels and should be provided using volume for volume earthworks. The use of voids, stilts or undercroft parking as mitigation for a loss in floodplain storage should be avoided and are not considered acceptable methods of compensation. Land that is required for current and future flood management shall be safeguarded from development.
16.4.14 The information provided in the SFRA should also be used as a basis for investigating potential strategic flood risk solutions, for example flood plain restoration, construction of new upstream storage schemes, and cross-boundary working.
16.4.15 Any protection and flood risk management measures that are required must be implemented and maintained. Where new defences are required, the residual risks should be identified and mitigated for, and the development should demonstrate significant flood risk betterment to offsite areas.
16.4.16 Where a development benefits from an existing or proposed flood defence scheme, the development should contribute towards the capital and/or maintenance of these defences over its lifetime.
16.4.17 Any proposed development located within an area protected by flood defences should identify the condition of these defences. Where they are in a 'fair' or 'poor' condition, or where the level of protection is not to the required standard, the flood defences should be improved to an agreed standard.
16.4.18 Where developments are proposed in areas with historic or ongoing flood risk issues, opportunities should be taken to reduce the existing risk of flooding. This may include reconnection of rivers to the floodplain, betterment of existing discharge rates and volumes, removal of redundant in channel structures, and integrating or retrofitting surface water measures to replace and/or augment an existing drainage system in a developed catchment.
16.4.19 In line with the sequential approach, flood risk on site should be reduced first by careful design to avoid the building being flooded (flood avoidance), then only if the sequential approach is not possible, constructing the building in such a way to prevent floodwater entering and damaging a building (flood resistance), then accepting that water may enter the building but designing it carefully to minimise damage and allow quick re-occupancy (flood resilience), and finally designing buildings to enable them to be quickly repaired or replaced after flood damage (flood repairable).
16.4.20 At the individual property level, measures to avoid site level flood risk, and improve resistance and resilience of buildings to flood risk will be required if buildings are situated in any flood risk area, in addition to safe access and egress during flooding events. This may include setting of floor levels at an appropriate level for the type and location of the development, and the potential restriction on ground floor bedrooms, in addition to resistance and resilience measures. New buildings should be designed and constructed in a way to prevent floodwater entering the building and damaging its fabric. Where water may enter the building it must be constructed in such a way as to ensure the impact is limited with no permanent damage, the structural integrity maintained, and drying, cleaning, replacement and repair is facilitated.
Development will be supported where:
- It is located in areas at lowest risk of flooding (from all sources) and the Sequential and Exception Tests (where required) demonstrate that the site is appropriate for development and its intended use.
- A sequential approach to site layout is applied, directing the most vulnerable uses to the areas at lowest risk from all sources of flooding.
- It will be safe for the lifetime of the development, will not increase flood risk elsewhere or result in a loss of floodplain storage capacity or impede flowpaths, and reduces the overall flood risk within and beyond the site boundary where possible. Land that is required for current and future flood management will be safeguarded from development.
- A site-specific assesment of flood risk has been undertaken following the criteria within this policy and the NPPF, which sets out appropriate flood risk management measures.
- Climate change implications are taken into account and occupants of the site will be safe during all flood events (including those which exceed the agreed design standard) or from residual risks or failure of the drainage system.
- Development must consider the impacts of the layout and land use on offsite flood risk. Measures should be identified and implemented, including passive measures to improve flood risk offsite.
- Surface water runoff is managed to pre-development rates and volumes, giving priority to the use of SuDS, and discharge locations have capacity to receive all foul and surface water flows from the development.
- The area of impermeable surface is minimised and porous and/or permeable surfaces are used wherever reasonably practicable.
- Mitigation measures maximise water efficiency and contribute to a net gain in water quality, biodiversity, landscape character and green infrastructure.
- Building level flood avoidance, resilience and resistance measures are designed into the development where appropriate.
Where necessary, planning permission will be conditional upon flood protection and/or runoff control measures being operative before other site works.
Development that increases the risk of flooding on or off the development site, or would compromise the performance of flood defences will not be permitted.
Central Bedfordshire Council will safeguard land required for current and future flood management.
16.5.1 Development adjacent to, or which encompasses any kind of watercourse will be considered "close to a watercourse" and should provide opportunities to improve or enhance the water environment. This could be through river restoration, backwater creation, de-silting, de-culverting, in-channel habitat enhancement and appropriate removal of structures. These watercourses will include the main river network, which fall under the Environment Agency's remit, Internal Drainage Board network, as well as other watercourses. These watercourses will be subject to Environment Agency, Internal Drainage Board and Central Bedfordshire Council Land Drainage byelaws, as well as the planning policies set out below. When designed properly, such measures can have benefits such as reducing the costs of maintaining hard engineering structures, reducing flood risk, improving water quality and increasing biodiversity. Social benefits may also be gained by enhancing green space and access to watercourses.
16.5.2 Building adjacent to the banks of a watercourse has the potential to cause problems to the structural integrity of the banks and the building itself and can make future maintenance of the watercourse more difficult. Development (including gardens) must therefore be set back from the watercourse and an undeveloped buffer strip of no less than 9m should be provided between the top of the bank and any proposed development.
16.5.3 Historically, many natural watercourses have been altered in some way, for example artificially straightened or culverted. The act of culverting a watercourse tends to have mainly negative effects for flood risk management, access, maintenance and on the amenity and biodiversity value of the watercourses. The Council therefore expects existing watercourses to remain open wherever possible for both flood defence and environmental purposes, and existing culverts removed. This includes ensuring that existing natural drainage features will be retained wherever possible. In exceptional cases where culverting is unavoidable, the length involved should be restricted to a minimum, with the hydraulic and environmental design assessed, and appropriate mitigating enhancements to the surrounding environment included. It must also be demonstrated that other options have been thoroughly explored before culverting will be considered.
16.5.4 Inappropriate planting can lead to the erosion of banks and beds of a watercourse, increase maintenance costs, reduce ecological potential and may even lead to the spread of invasive alien species which are detrimental to the wider ecology of the area.
16.5.5 New development is required to ensure that any landscaping and planting will:
- Enhance of the drainage characteristics of a scheme;
- Stabilise areas that may be vulnerable to erosion;
- Enhance the visual appearance of the development; and
- Enhance the ecological potential of the local environment, including optimum levels of light / shade for the watercourse.
16.5.6 Through the above measures, development close to a watercourse should contribute to the achievement of good status and help avoid deterioration of water quality in line with the requirements of the Water Framework Directive (2000/60/EC). The Directive is considered in Policy CC6.
Development should maximise opportunities for watercourse restoration and enhancement as part of the development. New development will be supported where it can be demonstrated that it will:
- Conserve, and where possible, enhance the ecological and flood storage value of the water environment.
- Incorporate and retain existing open watercourses and, where possible, open up existing culverts and create new watercourses within their site design.
- Provide a minimum 9m wide undeveloped buffer strip for access, maintenance and natural flood storage.
- Mimic features of natural river morphology and hydrology where alterations to the bank of an ordinary watercourse are proposed or which create a new watercourse as part of a sustainable drainage scheme. Where it is not practicable to do so compensatory measures will be provided.
- Maximise opportunities to refurbish and/or renew existing assets (e.g. bridges, culverts and river walls) to ensure their lifetime is commensurate with the lifetime of the development (an assessment of the condition of the assets will be required).
- Not involve any building on top of a culverted watercourse.
Development which would compromise access to watercourses, or compromise the performance of flood defence or navigation facilities will not be permitted.
16.6.1 The Council expects that all developments will use Sustainable Drainage Systems (SuDS) and all development is required to provide a drainage strategy. Approaches to manage surface water that take account of water quantity (flooding), water quality (pollution) biodiversity (wildlife and plants) and amenity are collectively referred to as SuDS. Development proposals will be required to demonstrate the proposed standards of operation, construction, structural integrity and ongoing maintenance of the proposed surface water drainage system.
16.6.2 SuDS should be designed to slow, reduce and treat surface water flow by natural means. Where appropriate, every effort should be made to link SuDS into wider initiatives to enhance green infrastructure, improve water quality, benefit wildlife and/or contribute to the provision of the ecosystem service. SuDS should enhance water quality and biodiversity in line with the Water Framework Directive (WFD), 'end-of-pipe solutions' where runoff is directly discharged into a wetland or pond should be avoided, and source controls should be incorporated to improve water quality.
16.6.3 The Council's adopted local requirements for the use of SuDS are:
- Plan in SuDs from the start
- Replicate natural drainage
- Water re-use first
- Enhance biodiversity
- Focus on multi-functional uses
- Minimise carbon and waste in SuDS
- Design for easy access and maintenance
- Linked design through every scale
- Place making through SuDS design
- Surface conveyance over pipes
16.6.4 The Council's adopted local requirements for SuDS are set out in full in the Supplementary Planning Document 'Central Bedfordshire Sustainable Drainage guidance: May 2015'. This provides technical guidance including how the Council will assess development proposals; the information required to accompany planning applications; the local requirements for SuDS; and guidance for how SuDS can be designed for the local environmental character.
16.6.5 The level of detail that must be provided at each stage of the planning process is also set out. This enables informed assessment of development proposals, in order to ensure appropriate and specific flood mitigation and sustainable drainage measures are in place. Information and links to the SPD can be found in the Environmental Framework, along with further information on national policy and standards.
16.6.6 In addition to the above, the design of surface water drainage must also comply with the 'Non-statutory technical standards for sustainable drainage systems' (March 2015, Ref: PB14308); Planning Policy Guidance paragraph 80, Building Regulations Approved Document H, the Central Bedfordshire Design Guide and other recognised best practice, including the CIRIA SuDS Manual and BRE 365, or as updated. Developers should also have regard to local evidence studies, such as the Marston Vale Surface Water Plan and other location specific studies.
16.6.7 The design of surface water drainage must reflect site-specific circumstances such as topography, underlying geology and ground conditions, as these will inform the appropriate use of SuDS. The Strategic Flood Risk Assessment (SFRA) gives an indication of the constraints across Central Bedfordshire and is intended to be used at a preliminary planning stage. Detailed site investigations will therefore need to be carried out to assess the suitability of a site for different types of SuDS and their detailed design. Where site investigations indicate that infiltration SuDS are suitable, these must be designed to mimic natural infiltration as much as possible.
16.6.8 Infiltration SuDS will not be appropriate in areas where surface water may be subject to contamination or where assessment demonstrates that risks to groundwater are unacceptable. Some developments such as mineral extraction or landfill may be required to undertake a Groundwater Risk Assessment.
16.6.9 Discharge methods for surface water runoff should comply with Planning Practice Guidance paragraph 80 and Building Regulations Approved Document H and should ease pressure of the development downstream by reducing the impact of surface runoff entering a receiving waterbody or drainage network. Brownfield sites are expected to mimic greenfield runoff rates as far as possible, and at a minimum provide a betterment of at least 30% of the existing discharge.
16.6.10 To ensure SuDS continue to function as designed for the lifetime of the development which they serve, new development proposals should include a 'management and maintenance plan'. This should set out arrangements for adoption (if applicable), maintenance activities, access to and responsibilities for public and private components of the system.
The Council expects all development to use SuDS as normal practice, giving priority to naturalistic solutions incorporated into the soft landscape of the development.
All development that results in increase in hard standing area or impacts on surface water flow paths must therefore:
- Demonstrate that the surface water drainage is compliant with local requirements and design guidance set out in the Council's Sustainable Drainage SPD, National Standards and industry best practice.
- Design SuDS to deliver multiple environmental benefits, including flood risk and water quality management, biodiversity and landscape enhancement, and improve amenity, access and open space.
- Demonstrate that the discharge of surface water obeys
the following priority order:
- firstly, to ground via infiltration;
- then to a water body at a rate no greater than greenfield runoff;
- then to a surface water sewer at a rate no greater than greenfield runoff for greenfield sites, or at a rate to be agreed (as close to greenfield as possible, but a minimum betterment of 30% of the existing discharge) for previously developed land.
- Discharge to a foul water or combined sewer is unacceptable, unless in exceptional circumstances where it can be demonstrated that there are no feasible alternatives and that it will not result in increased flood risk on or off site.
- Demonstrate that surface water runoff is managed as close to its source as possible and flow and quality of the runoff is manged in stages.
- Demonstrate that the run-off from all hard surfaces shall receive an appropriate level of treatment to minimise the risk of pollution.
- Show that suitable testing has been carried out to demonstrate whether infiltration is possible and that ground water would not be polluted. This may include undertaking a Groundwater Risk Assessment.
- Identify ownership and maintenance responsibilities for the entirety of surface water drainage system and include a 'management and maintenance plan', which shall include the arrangements for adoption by any public authority or statutory undertaker and any other arrangements to secure the operation of the drainage scheme throughout its lifetime.
In exceptional circumstances, where a sustainable drainage
system cannot be provided, it must be demonstrated that it
is not possible to incorporate sustainable drainage
systems, and an acceptable means of surface water disposal
is provided at source which does not increase the risk of
flooding or give rise to environmental problems and
improves on the current situation with a reduction in peak
and total discharge.
16.7.1 The Council will seek to ensure that there is adequate water supply, surface water, foul drainage and sewerage treatment capacity to serve all new developments. The provision of new waste water treatment facilities is covered by policies in the Adopted Minerals and Waste Local Plan.
16.7.2 The Council's preferred approach for foul drainage disposal is that new development will connect to the public sewerage system at the nearest point where capacity exists, this may require off-site infrastructure. Other options (e.g. private sewage treatments, septic tanks, cesspits or other more sustainable forms of sewage treatment) should only be considered if it can be clearly demonstrated by the developer that disposal to the public foul sewer is not feasible, taking into account cost and/or practicability.
16.7.3 Developers will be required to demonstrate the capacity in the sewerage system, on and off the site, and whether this is adequate to serve the development. A full assessment of the existing network against the scale of the development and its potential phasing should be provided to ascertain whether connection of the proposed development would lead to overloading of existing infrastructure and the need for the provision of any additional process plant and works capacity etc. Where there is a capacity problem and no improvements are programmed by the Water and Sewerage Company, the Council will require the developer to identify and fund appropriate improvements which must be completed prior to occupation of the development. The relevant water and sewerage companies must be consulted.
16.7.4 Drainage on the site must maintain separation of foul and surface flows. An existing connection to a sewer does will not automatically set a precedent and it must be demonstrated why infiltration and/or a connection to a watercourse cannot be utilised, in these instances removal of surface water currently draining to a combined sewerage system or is misconnected to the foul sewerage system is expected.
Policy CC6: Water supply and sewerage infrastructure
Planning permission will only be granted for developments where it can be demonstrated that:
- adequate water resources are available, or can be provided, and will be safeguarded from the potential impacts of development,
- foul flows produced by the development will be drained separately from surface water run off to an agreed point of connection to a public foul sewer or, for non mains drainage proposals, where there would be no detrimental impact on the environment, and
- foul sewers and sewage treatment facilities (of adequate design and capacity) are available to meet the demand created by new development or, where they are not available, can be provided in time to serve the development to ensure that the environment and the amenity of local residents are not adversely affected
In accordance with Planning Policy Guidance, when there is a capacity constraint and improvements in off-site infrastructure are not programmed, planning permission will only be granted where the appropriate infrastructure improvements to the satisfaction of the relevant water and sewerage undertaker will be completed prior to occupation of the development.
Development which would overload available facilities and
create or exacerbate problems of flooding or pollution will
not be permitted.
16.8.1 The Water Framework Directive (WFD) and the Groundwater Directive recognises that development near water bodies can affect their quality and ecology. It establishes a legal framework for the protection, improvement and sustainable use of the water environment. This includes lakes, streams, rivers, groundwater and dependent ecosystems. The Environment Agency's River Basin Management Plans (RBMP) for the Anglian and Thames Districts (including the Ouse catchment and Lea catchment) are the lead policy documents that cover WFD matters in Central Bedfordshire, and place further constraints on new development in terms of its influence on the quality status of receiving water bodies.
16.8.2 Many of the watercourses in Central Bedfordshire already meet the 'good' overall WFD status including the Clipstone Brook, the River Ivel (upstream of Henlow) and the Ickwell Brook. However, the majority only meet 'moderate' overall status or less. It is important that developments aim to take positive measures to conform to the WFD, which can be impacted as a result of development, for example in terms of 'deterioration' in ecological status or potential. More information on water quality in Central Bedfordshire is provided by the Environmental Framework.
16.8.3 Development in close proximity or which discharges to a waterbody must carry out a WFD assessment demonstrating that it will not lead to deterioration in the overall status of the waterbody, or prevent future attainment of good status. Where there are no apparent watercourses nearby, consideration should still be given to WFD objectives given that all water eventually makes its way into the river system.
16.8.4 Development should deliver opportunities to enhance the quality of the water environment, for example by:
- Integrating SuDS and green infrastructure into new development;
- Managing and where possible reducing the risk of water pollution
- Reducing the effects of flooding and drought on water bodies, and the prioritisation of naturalistic flood defence over the provision of hard flood defences
- Making modification to watercourses to restore 'natural' systems, including de-culverting, restoring or re-profiling rivers and naturalising river banks
- Adopting water efficiency measures;
- Restoration of contaminated land
- Opportunities identified by Catchment Partnerships and flood risk management authorities should inform development proposals
16.8.5 Early consideration of the water environment will enable water quality aims and outcomes to be secured through the planning process. By integrating SuDS into new developments and redevelopments, and through using these in sequence, it is possible to minimise pollutants which may be generated by a development. This in turn will help conform to the water quality objectives of the Water Framework Directive, as well as reducing flood risk. The design of SuDS is considered in Policy CC5.
Policy CC7: Water Quality
Any development that would have a direct impact on any watercourse (e.g. re-alignment of a river or work to bridges) should demonstrate consideration of the impact of their development on water quality.
All new development must demonstrate:
- That it has no adverse impact on the quality of waterbodies and groundwater, or will prevent future attainment of good status
- That development contributes positively to the water environment and its ecology and does not adversely affect surface and ground water quality;
- How they have contributed to the protection and enhancement of waterbodies identified by the Anglian and Thames River Basin Management Plan objectives, covering the Ouse and Lea catchments
For any water body that is already in the lowest status
class (including poor groundwater quantitative status)
under the WFD, the Council will expect development to
deliver enhancements where rivers and lakes are not
achieving good ecological status or potential. Development
that would result in deterioration shall not be permitted.
A Groundwater Risk Assessment will be needed to support a
planning application where activities could directly or
indirectly pollute groundwater.
16.9.1 An important aspect of providing sustainable development is maintaining a healthy environment and protecting public health, wellbeing and amenity, through the control of pollution. Pollution can cause adverse health risks, damage the environment and interfere with amenity. It can also adversely affect neighbouring land uses, cause long term contamination and hinder regeneration.
16.9.2 Some development has the potential to harm the environment and impact public health in a variety of ways, including the emission of pollutants to the air (including odour), water courses and soils (including land contamination), and the generation of noise, vibration, light, litter and pests. The Council will consider the possible polluting effects of a development proposal on aspects such as amenity and surrounding land uses and other receptors such as the effect on biodiversity and the water environment..
16.9.3 In addition to pollution, the NPPF makes it clear that all development should take account of ground conditions, including suspected or confirmed land contamination, and land instability in order to ensure that sites are suitable for its new use and that any uses do not have any unacceptable adverse impacts on human health, property and infrastructure, the natural and historic environment.
16.9.4 The Council will seek to maintain sustainable and healthy environments through the careful consideration of development proposals which are likely to cause or be exposed to potential sources of pollution,or, cause or be affected by land instability. Applicants will be required to submit an assessment of the extend of pollution and, or land instability that identifies possible risks and demonstrates that the conditions can be suitably mitigated for the proposed end use, as set out in the current national guidance, the Central Bedfordshire Design Guide or any site specific Development Briefs or Masterplans.
All proposals for new development must demonstrate compliance with the current national guidance as well as the Council's adopted standards and supplementary planning guidance in terms of pollution and land instability. Pollution includes matters in relation to noise, waste management, vibration, odour, surface and ground waters, light, contaminated land and airborne pollution.
Development proposals which are likely to cause pollution or land instability, or are likely to be exposed to potential unacceptable levels of pollution or land instability will only be permitted where it can be demonstrated that:
- measures can be implemented to minimise impacts to an acceptable level which protects health, natural and historic environment, water quality, property, infrastructure and amenity; and
- conditions can be suitably mitigated for the proposed end use and cause no adverse effects;
Where necessary the Council will use planning conditions and/or legal agreements to help limit the impact of pollution.