DMD 49 Sustainable Design and Construction Statements All new development must achieve the highest sustainable design and construction standards having regard to technical feasibility and economic viability. All development will be required to include measures capable of mitigating and adapting to climate change to meet future needs having while regard to technical feasibility and economic viability. All planning applications must be accompanied by a Sustainable Design and Construction Statement, to demonstrate compliance with Development Plan policies in accordance with the details set out in Appendix 3: Sustainable Design and Construction Statement. This Policy should be read in conjunction with Core Strategy policies 4, 20, 21, 22 and 31. |
Justification and guidance on implementation
8.1.1 The Council is committed to achieve the highest standards for sustainable design and construction within the Borough. The Council acknowledges that a measure of sustainability is not limited to energy efficiency, but is expressed over a range of relevant measures: environmental, social and economic. The policies contained within the Core Strategy and throughout this document represent key sustainability milestones to achieve local, regional and national commitments for the delivery of sustainable development and it is essential that the planning process, charged with the delivery of such targets, deploy appropriate, consistent and transparent tools to assess the relative sustainable merits of individual developments and continue to monitor the development over its lifetime.
8.1.2 Consistent with Policy 5.3 of the London Plan and the Mayor's associated Sustainable Design and Construction Supplementary Planning Guidance, developments are required to demonstrate that they have achieved the highest possible standards of sustainable design and construction.
8.1.3 The contents of the statement are designed to encourage developers to engage with the principles of sustainable design and construction at the earliest possible point in the design process and cultivate a culture of change in the development process that will encourage innovation to realise the strategic objectives of the plan. The Sustainable Design and Construction Statement should be used to demonstrate compliance with relevant policies contained throughout this document and should be accompanied with relevant validation documents and assessments under the Code for Sustainable Homes and BREEAM as detailed in policy DMD 50 'Environmental Assessment Methods'.
DMD 50 Environmental Assessment Methods The Council will require developers to demonstrate compliance with targets relating to the relevant adopted environmental assessment methods. 1. New build residential development
Proposals must achieve the following standards under the Code for Sustainable Homes, or equivalent scheme or rating if this is updated:
b. Minor Development Proposals must achieve Code Level 4 (or equivalent rating if this scheme is updated) where it is technically feasible and economically viable to do so. 2. Residential refurbishments and conversions
Proposals must achieve the following standards under the BREEAM Domestic Refurbishments standard, or equivalent rating/scheme if this is replaced or updated:
b. Minor Development Proposals must exceed a ‘Very Good’ rating under the BREEAM Domestic Refurbishments standard, or their equivalent rating/scheme. 3. Non-residential development
Proposals must achieve the following standards under the relevant BREEAM 2011 scheme or equivalent rating/scheme if this is replaced or updated:
Where appropriate, minor non residential development will be required to submit the relevant BREEAM 2011 (or replacement/equivalent) pre-assessment for consideration in accordance with the Scope Section of the BREEAM Scheme Document, or replacement. There may be exceptional circumstances where other planning requirements or site characteristics mean that the required level of the Code/BREEAM cannot be met (including technical feasibility and economic viability). Unless such circumstances exist and are clearly demonstrated then planning permission will not be granted for proposals which fail achieve the targets. This Policy should be read in conjunction with Core Strategy policies 4, 20, 21, 22, 28, 31,32 & 36. |
Justification and guidance on implementation
8.1.4 The developer should demonstrate how the relevant Level of the Code for Sustainable Homes or category of BREEAM assessment will be met through the submission of a pre-assessment to accompany the application. A combination of the sustainable design and construction statement and the results of the pre-assessment will form the basis of the condition and potentially a S106 Planning Obligation for the final development. The pre-assessments must be assessed on the most detailed evidence available at the time of submission and should be undertaken by a qualified and licensed assessor.
8.1.5 If planning permission is granted,developments will be required to submit additional evidence in the following formats and at the following times for the consideration of the Local Planning Authority:
8.1.6 This policy is consistent with Core Strategy Policy 20 and the requirements of the National Planning Policy Framework (NPPF) and Policy 5.3 of the London Plan. The Renewable Energy and Low Carbon Study for Enfield (2010) concluded that the additional costs associated with meeting advanced Code levels and BREEAM ratings are relatively modest for most elements and that higher CSH and BREEAM ratings are already being achieved by developments within the borough. A significant proportion of the costs of delivering the respective standards are absorbed by meeting relevant energy efficiency standards. It is likely that these costs could be reduced further through effective supply chain management, economies of scale from the bulk purchase of materials and fittings, and innovation in design within the housing and commercial sectors, as construction practices and available technologies evolve in tandem with improved standards.
8.1.7 Viability varies across the borough. The 2013 Community Infrastructure Levy and Development Management Viability Assessment indicates that the achievement of code level 5 for sustainable homes may not be viable for some sites in the eastern part of Enfield (east of the A10). For sites located in the east, achievement of code level 4 or equivalent may be acceptable, if robust evidence is submitted with the application to demonstrate that achievement of higher standards is not viable.
DMD 51 Energy Efficiency Standards All developments will be required to demonstrate how the proposal minimises energy-related CO2 emissions in accordance with the following energy hierarchy:
Measures to secure energy efficiencies and reduce the emissions of CO2 must adhere strictly to the principles of the energy hierarchy with each tier utilised fully before a lower tier is employed. Developers must submit detailed Energy Statements in accordance with DMD 49 'Sustainable Design and Construction Statements' to demonstrate how they have engaged with the energy hierarchy to maximise the energy efficiency of the proposal. Specific targets for energy efficiency will apply to the following types of development: Residential Development The Council will require all major residential developments to achieve as a minimum:
Non-residential proposals The Council will require major non-residential development involving the replacement or creation of new non-residential floorspace or a combination thereof to achieve as a minimum:
All of the reductions specified for residential and non-residential development above should be provided on-site. Where site constraints preclude attainment of the required reductions and/or the reductions are not technically feasible and this has been evidenced through the Energy Statement, in accordance with DMD 49 'Sustainable Design and Construction Statements' provisions for providing near-site or off-site reductions through a set of agreed allowable solutions or financial contribution will be required to fully off-set the shortfall. For minor development, the Council will seek to encourage all residential or non-residential developments to achieve the above targets where it is demonstrated that this is technically feasible and economically viable. Developers will be required to take account of unregulated CO2 emissions within their energy statements and will be required to reduce energy consumption for these uses so far as practicable. This Policy should be read in conjunction with Core Strategy Policy 20 . |
Justification and guidance on implementation
8.2.1 Policy 5.2 of the London Plan sets out targets for carbon dioxide reduction for both residential and non-residential development up to 2031 and forms the backbone of energy efficiency targets for the borough as a whole. The Policy embeds the principles of the energy hierarchy (be lean, be clean, be green).
8.2.2 The Renewable Energy and Low Carbon Development Study (2010) demonstrates that the policy will deliver higher CO2 savings and provide a greater incentive for developers to install on-site district heating infrastructure than a policy that simply defaults to building regulation compliance.
8.2.3 Clear implementation and monitoring of the CO2 reduction policy will be a priority and the policy has been designed to facilitate this. All relevant schemes will be expected to submit an Energy Statement demonstrating how they comply with the policy. Implementation of the target total CO2 reduction level in any approved scheme should then be independently verified through nationally recognised, independently audited schemes, such as Energy Performance Certificates, the Code for Sustainable Homes (for new build residential developments) and BREEAM (for all other developments) and recorded by the relevant monitoring officer in Council. These figures, including a clear breakdown of the percentage of carbon savings delivered by fabric efficiency, connection to DEN, through the use of renewables and ultimately carbon offsetting, will feed into Enfield's Sustainability Programme.
Decentralised Energy Generation
8.2.4 Decentralised Energy (DE) systems generally consist of communal, site-wide or district heating and cooling networks served by technologies such as combined heat and power (CHP) or combined cooling heat and power (CCHP) or boiler plants fuelled by gas, biomass or energy from waste technologies. DE systems have the potential to reduce carbon dioxide emissions from energy use in new and existing development. By generating low carbon heat and/or power at or near the point of use, DE networks at all scales make more efficient use of primary energy sources.
8.2.5 Although in the past DE networks have mainly been based around gas-fired CHP/CCHP or boiler plants, the future potential for DE networks fuelled by alternative renewable sources of energy such as biomass and energy from waste (EfW) technologies is becoming increasingly recognised. DE networks are flexible in that they allow for conventional energy technologies to be replaced by renewable sources as fossil fuels become less viable.
DMD 52 Decentralised Energy Networks Proposals for the development of decentralised energy network infrastructure and related apparatus in the borough will be supported. The Council will support, and in some cases facilitate, the provision of infrastructure to support new and expanding networks including safeguarding routes and land for such use where necessary. Proposals for major developments which produce heat and/or energy should contribute to the supply of decentralised energy networks unless it can be demonstrated that this is not technically feasible or economically viable. Connection to a decentralised energy network All major developments should connect to or contribute towards existing or planned DE networks supplied by low or zero carbon energy. 1. Where the proposed development is adjacent to an existing DE network, it should:
2. Where there is an existing DE network that requires extension in order to supply the proposed development, proposed developments should:
3. Where there is a planned DE network within feasible and viable range of future connection, proposed developments should:
4. Where there is no connection available to a decentralised energy network and no DE network is planned within range, on-site CCHP or CHP will be expected where the heating demand makes it feasible. 5. Where CCHP or CHP would not be technically feasible or financially viable, developments will be required to be designed to enable its connection to a decentralised energy network in the future, or provide a contribution for the expansion of decentralised energy networks, or other carbon reduction measures within the borough, where reasonable and appropriate. 6. Where technically feasible, buildings with high cooling loads that are connected to a DE network should be designed to meet their cooling demand through heat-fed absorption chilling. This policy should be read in conjunction with Core Strategy Policy 20. |
8.2.6 Justification and guidance on implementation
8.2.7 Decentralised energy generation is supported by national and regional planning policy as a means of meeting the requirements of the Climate Change Act to reduce carbon emissions by 80% on 1990 levels by 2050. The Mayor of London has set a target that 25% of heat and power used in London is to be generated through the use of localised decentralised energy systems by 2025.
8.2.8 The Core Strategy sets a framework to support appropriate measures to mitigate and adapt to the impacts of climate change. Core Strategy Policy 20 requires carbon dioxide emissions from developments to be minimised by following the steps of the energy hierarchy. Step 2 ensures that developments have done all they can to obtain an efficient supply of energy. The Council will expect developments to connect to a decentralised energy network unless it can be demonstrated it is not technically feasible or financially viable.
8.2.9 The Council is working closely with neighbouring boroughs, the GLA and other partners on the development of the Lee Valley Heat Network . This new city-scale decentralised energy network will capture affordable low carbon heat from waste to energy facilities and combined heat and power plants, supplying it to buildings and industry across the Lee Valley. It is intended that the Lee Valley Heat Network will initially use heat and steam from the Energy from Waste (EfW) facility at the Edmonton Eco Park, moving energy in the form of hot water and/ or steam through a system of pipes to where it is needed. Over time the network will connect additional heat sources elsewhere in the Lee Valley.
8.2.10 Feasibility work 1 2 has confirmed that this strategic network can deliver heat to sites across the Lee Valley, including those in Enfield, and will deliver significant economic, environmental and social benefits. These include facilitating inward investment and new jobs, providing affordable low carbon heat to residents, businesses, industries and the public sector, helping to tackle fuel poverty by reducing heating costs and reducing London’s carbon footprint.
8.2.11 There is potential to bring the network forward by means of a Local Development Order (LDO), which would grant permission for works comprising but not limited to pipes, heat exchange equipment and ancillary engineering works in the borough. The provisions of the LDO will include specific conditions to deal with proposed infrastructure in sensitive locations and subject to relevant material considerations including but not limited to: appearance; highways impacts; access; and servicing. Applicants intending to use a LDO would apply to the Council for prior approval, enabling delivery of the network to be monitored.
8.2.12 In determining whether a development is suitable to connect to a decentralised energy network or to include combine cooling, heat and power, the Council will consider the heat demand of the development and its proximity to a decentralised energy network as well as the feasibility and viability of connecting or including plant equipment. The Council will apply a general presumption that where the opportunity exists to generate heat on-site or to connect to a DE network, the latter will be sought in all cases unless it can be demonstrated that a significantly greater reduction in carbon emissions can be achieved by generating heat on-site, or connection to a network will have an adverse impact on the operation of the network.
8.2.13 Developments and areas with the following characteristics will be suitable for decentralised heat:
8.2.14 The Council will take into account the design standards and specifications for district energy networks set out in the Mayor of London’s “District Heating Manual for London” (2013), in the implementation of DMD 52 'Decentralised Energy Networks', and the determination of relevant planning applications. Where connection to an existing or future decentralised energy network is feasible and viable, a commitment to a connection may be secured via a legal agreement.
DMD 53 Low and Zero Carbon Technology Where major developments have secured all possible savings through energy efficiency and decentralised energy networks and still fail to achieve the specified carbon dioxide reductions targets (DMD 51 'Energy Efficiency Standards'), developments will be required to provide on site renewable energy generation through the use of low and zero carbon technologies. Developments will be required to make-up the identified shortfall or provide a 20% carbon dioxide reduction, whichever is the greater unless it can be demonstrated that this is not technically feasible or economically viable. For minor applications, the Council will seek to encourage further carbon dioxide reductions through the provision and use of on-site renewable energy generation and the use of low and zero carbon technologies. Local opportunities to contribute towards decentralised energy supply from low and zero carbon technologies will be encouraged, where there is no overriding adverse local impact including identified impacts to historic assets. Where proposals are located within the Green Belt, elements of many low and zero carbon energy projects would constitute inappropriate development, which may impact on the openness of the Green Belt, the established character of the landscape or its biodiversity. In evaluating the development, the Council will give significant weight to the visual impacts of the project, the potential for disturbance to neighbouring properties and specific ecological considerations. Developers will need to demonstrate very special circumstances that clearly outweigh any harm by reason of inappropriateness and that there are no overriding local impacts for an application to be approved. This Policy should be read in conjunction with Core Strategy Policy 20 . |
Justification and guidance on implementation
8.2.15 The use of low and zero carbon technologies can make a valuable contribution to reducing carbon emissions at both the macro and micro scale. They are directly beneficial to the subject development, but also serve to decarbonise the grid through feeding back excess energy at times when the development has low energy demands. It is unlikely that required energy efficiency savings can be secured by focusing on fabric efficiency alone and where connection to a Decentralised Energy Network is not feasible, the use of low and zero carbon technology will become standard practise in the medium to long term.
8.2.16 The Council will seek to encourage the provision of large scale systems only where there is no overriding adverse local impact.
DMD 54 Allowable Solutions Where developers can demonstrate that the attainment of targets specified in DMD 51 'Energy Efficiency Standards' are not technically feasible or economically viable, the Council will seek a financial contribution to off-set the identified short fall. This will be calculated on the basis of a price per tonne of carbon required to address any short fall. This Policy should be read in conjunction with Core Strategy Policy 20. |
Justification and guidance on implementation
8.2.17 Whilst the principles of the energy hierarchy must be observed and the vast majority of savings will still be required on-site, provision has been made to secure cash-in-lieu contributions where it is clearly demonstrated that the specific targets cannot be fully achieved on site, any shortfall may be provided off-site.
8.2.18 Any funds captured will be ringfenced and spent only on local measures that provide real and measurable reductions in carbon emissions. These can include, but are not limited to:
8.2.19 The adoption of the S106 SPD (November 2011) sets out a formula for calculating financial contributions to offset carbon emissions.
DMD 55 Use of Roof Space/ Vertical Surfaces New-build developments, and all major development will be required to use all available roof space and vertical surfaces for the installation of low zero carbon technologies, green roofs, and living walls subject to technical and economic feasibility and other relevant planning considerations. Evidence demonstrating the feasibility of complying with this Policy should form part of the sustainable design and construction statement. Where renewable technologies are proven to be feasible, developers are required to give due regard to the Energy Opportunities Plan (EOP) and Opportunity Area Planning Framework (OAPF) and where possible feed into an existing or proposed DEN or district heating network. This Policy should be read in conjunction with Core Strategy policies 20, 21 & 36 . |
Justification and guidance on implementation
8.2.20 The utilisation of vacant roof space and vertical surfaces can make an essential contribution to tackling climate change. Well designed roofs and walls can realise the objectives of policies throughout the Local Plan without undermining the viability of developments and represents a truly multi-benefit resource. Well designed roofs and walls can:
8.2.21 Green roofs are required to maximise benefits for biodiversity, sustainable drainage and cooling. Extensive green roofs provide the widest environmental benefits and therefore a presumption for this type of green roof should be adopted in all cases. Extensive green roofs are required to have a substrate depth of 75-150mm, unless it can be demonstrated that this is not reasonably possible. The substrate depth should be varied within this range to maximise biodiversity benefits.
8.2.22 The level of green roof/ living wall provision will be assessed on a site-by-site basis, taking account of relevant plant installations, orientation, pitch and the function of the roof space. Other relevant planning considerations including heritage issues will inform negotiations with developers. Alternative types of green roofs may be appropriate where technical constraints or the need to provide viable amenity provision can be demonstrated. For further guidance on relevant technical considerations for installing living roofs or walls, reference should be made to the ‘Living Roofs and Walls’ technical report which accompanies London Plan Policy 5.11. Where roof space is required for recreational use, the Council will adopt a presumption for the provision of intensive green roofs.
8.2.23 Not all roofs are capable of incorporating green roof/ living wall or indeed low and zero carbon installations, due to locational constraints, design or orientation, however, the vast majority of developments are capable of accommodating the relevant installations if they are considered from the inception of the scheme. Technical constraints, including load bearing capabilities of the roof structure, can be ‘designed out’ of the final development. Through the sustainable design and construction statement developers are encouraged to engage with the feasibility of this policy’s requirements at the earliest possible stage in the design process. Where it is claimed that such installations are not technically feasible or economically viable, this must be clearly evidenced within the sustainable design and constructions statement. The viability of a scheme is unlikely to be greatly affected as a result of implementing this policy. Green / brown roofs and / or low and zero carbon technologies present design solutions to the energy efficiency targets contained within this document at a cost commensurate with carbon abatement schemes.
DMD 56 Heating and Cooling All new developments (excluding householder applications) will be required to demonstrate how the scheme has been designed to control and manage heat gain and reduce the reliance on mechanical cooling, subject to technical and economic feasibility and other relevant planning considerations. Development proposals should reduce their reliance on mechanical cooling systems in accordance with the following hierarchy:
Measures to manage the heating and cooling demands of development must adhere strictly to the principles of the cooling hierarchy with each tier utilised fully before a lower tier is employed. Where mechanical ventilation/cooling plant is present in a scheme, evidence must be provided to demonstrate that the heating and cooling demands of the development cannot be met by alternative means. Opportunities to adapt to existing buildings, places and spaces to manage heating and cooling demands must be maximised where practicable. This Policy should be read in conjunction with Core Strategy Policy 20. |
Justification and guidance on implementation
8.2.24 The most recent data presented in the UK Climate Change Projections 2009 suggest that by the 2080s, the UK will see an average temperature rise of between 3.9 and 4.2 degrees. In urban locations with higher densities and a tight urban fabric, it is likely that such increases in temperature are intensified in comparison to more rural locations by a process known as Urban Heat Island Effect (UHIE). Ensuring buildings are designed and constructed to be comfortable in higher temperatures, without resorting to energy intensive air conditioning, is a corner stone of climate change adaptation. By engaging with the principles of the cooling hierarchy, this Policy will require developments to incorporate measures which will ensure adaptation to rising summer temperatures, but in a way that will minimise energy intensive cooling strategies over the lifetime of the development.
8.2.25 Careful management of development can not only minimise the need for cooling in the summer months, but in winter can also serve to reduce the cost of heating. Poorly designed buildings exacerbate the need to artificially heat space to provide a comfortable environment.
8.2.26 Developers are required to submit supporting evidence through their sustainable design and construction statement to demonstrate how the principles of the cooling hierarchy have been addressed within the proposal, including, where necessary, an explanation of how the hierarchy has influenced the evolution of the design to incorporate passive solar design methodologies. Consistent with urban design policies contained within this document, developers are encouraged to engage with the Local Planning Authority at pre-application stage to establish a dialogue that will inform the layout and design of the scheme. The potential for abstraction from the borough's rivers and canals to deal with heating and cooling demands, particularly within the Lee Valley, should be explored. Proposals for abstraction will be measured against other material considerations including water quality, flood risk, biodiversity and ecological implications as well as appearance.
DMD 57 Responsible Sourcing of Materials, Waste Minimisation and Green Procurement All major developments are required to ensure materials used in construction are responsibly sourced subject to technical and economic feasibility and other relevant planning considerations. As a minimum development will be required to achieve the following credits under the Materials category of the Code for Sustainable Homes and BREEAM or equivalent rating/scheme if this is replaced or updated:
In addition 100% of timber used on the project must be sourced in accordance with the UK Government’s Timber Procurement Policy. A Site Waste Management Plan will be required for all Major Developments (and those defined under the Clean Neighbourhoods and Environment Act 2005) to demonstrate procedures for the minimisation of construction waste consistent with the principles of the waste hierarchy: reduce; reuse; recycle; recover. As a minimum, development will be required to divert at least 85% of non-hazardous waste by weight or volume from landfill with a strategic objective to divert a minimum of 95% of waste by weight or volume by 2020. All new development should:
All major developments are required to include a Green Procurement and Construction Plan detailing how the development has sought to minimise the environmental impact of the scheme through responsible sourcing of materials, minimising construction site impacts, local procurement and employment strategies and the minimisation of construction and demolition waste. This Policy should be read in conjunction with Core Strategy Policies 20, 22 & 32 . |
Justification and guidance on implementation
8.3.1 This policy seeks to lower the environmental impact of materials over their life-cycle while addressing the wider impact of demolition and construction works.
8.3.2 The sustainable design and construction statement contains sections dedicated to materials and waste where developers are required to demonstrate how materials are being sourced and how waste from site is being dealt with for all developments. The level of detail required will be commensurate with the scale and scope of the scheme.
8.3.3 For major developments, assessments under the Code for Sustainable Homes and BREEAM should be used to demonstrate compliance with credit targets above. This will form the basis of a condition in any consent.
8.3.4 Site Waste Management Plans (SWMP) are required by law for all developments where the construction costs reach £300,000 by virtue of the Clean Neighbourhoods and Environment Act 2005. Consistent with requirements set out in the London Plan, the submission of SWMPs will be a validation requirement in the determination of planning applications. The level of detail provided will be commensurate with the scale and scope of the scheme and any information provided will form the basis of a condition in any consent.
8.3.5 As part of the sustainable design and construction statement all major developments will be required to submit a Green Procurement and Construction Plan.
8.3.6 The ability of individual developments to achieve the targets stated will be assessed on a site-by-site basis subject to technical feasibility and economic viability testing.
DMD 58 Water Efficiency In accordance with Core Strategy Policy 21 and the objectives for water efficiency set out in the London Plan all new development will be required to maximise its water efficiency, subject to technical and economic feasibility and other relevant planning considerations. A. Residential Development New residential development, including new build and conversions, will be required to achieve as a minimum water use of under 105 litres per person per day. Major residential development will be required to achieve as a minimum, the following standards unless it can be demonstrated that it is not technically feasible to do so:
B. Non Residential Development The Council will require major non-residential development involving the extension, replacement or creation of new non-residential floorspace or a combination thereof to exceed the following standards under WAT1 of BREEAM 2011 or equivalent rating/scheme if this is replaced or updated:
An assessment of the efficiency of the building’s domestic water consuming components is undertaken using the BREEAM Wat 01 calculator. The water consumption (litres/person/day) for the assessed building is compared against a notional baseline performance. For all other developments including changes of use, conversions, extensions and refurbishments captured by the planning process, the highest level of water efficiency will be sought. Greywater Collection The Council will seek to encourage the inclusion of rainwater collection and greywater recycling. All new major developments should undertake a rainwater and greywater use feasibility study. Where collecting and reusing water is feasible, it should be included in the proposed development. This Policy should be read in conjunction with Core Strategy Policy 21 and 46. |
Justification and guidance on implementation
8.4.1 The Environment Agency’s publication ‘Areas of Water Stress: Final Document' (2007) indicates that Enfield is an area of serious water stress. The major water sources that supply the borough are the River Lee, River Thames and the Chalk aquifer beneath the London Clay. The public water supply sources in the Lower Thames and Lee Rivers make up 79% of total freshwater abstracted in London. The water resource status of these major water sources indicate that the sources are already ‘over abstracted’.
8.4.2 Residents within the borough consume 166 litres of water per person per day, significantly more than the national average (146 litres/person/day). These levels of consumption are already unsustainable. Increased population forecasts, additional growth in housing and non-residential floorspace will place significant additional pressure on already scarce water resources. Moreover, with the onset of climatic change, future rainfall is expected to become more seasonal, with more rainfall falling in winter (up to 30% more by 2080s) and less in summer (up to 50% less by 2080s). Although the annual average volume of precipitation is not expected to decrease, it will fall less evenly throughout the year than currently experienced, with a greater proportion falling in intense downpour events. This will lead to increased flooding, but also more frequent and longer dry periods where the borough will be forced to rely on reservoirs to meet its needs and exacerbating water stress.
8.4.3 In accordance with the Water Framework Directive, DMD 58 seeks to set challenging, but ultimately achievable standards for water efficiency within development commensurate with requirements to comply with targets for development under the Code for Sustainable Homes and BREEAM. Based on research conducted by the Environment Agency(13) the targets for residential development can be achieved without incurring significant additional costs. Consistent with Policy 5.15 of the London Plan and the Climate Change Strategy, the Council is committed to explore the concept of ‘water neutrality’ and this Policy seeks to encourage the developments to utilise rain and grey water harvesting systems as alternative water sources to reduce consumption.
8.4.4 There may be exceptional circumstances where other planning requirements or characteristics mean that the required water efficiency target cannot be met (including technical feasibility and economic viability). Unless such circumstances exist and are clearly demonstrated then planning permission will not be granted for proposals which fail achieve the targets.
8.4.5 A major upgrade is being planned for the Deephams Sewage Works during the plan period, to meet new environmental standards and to accommodate growth within the catchment. The principal of the upgrade is supported as being necessary to deliver infrastructure to meet existing and future wastewater demands.
8.4.6 Developers for all planning applications will be required to demonstrate, through the Sustainable Design and Construction Statement, that all measures have been taken to reduce the consumption of mains potable water through the use of water efficient fittings, flow restrictors, efficient appliances and water recycling/harvesting systems where feasible. In addition all development proposals will be required to demonstrate that there is sufficient water supply infrastructure both on and off site to serve the development. Major development will be required to submit relevant water consumption calculations as required by the Code for Sustainable Homes and BREEAM.
8.4.7 The Council recognises that in the case of outline non-residential uses the end-user for the development may not have been identified. In this regard, developers will need to demonstrate how water efficiency can be addressed through construction and fit-out and this will form the basis of a suitably worded condition if the scheme is approved.
8.5.1 Enfield's waterways are a valuable asset for the borough, they provide water resources for London, opportunities for sport, recreation and leisure, access to nature, a historical reference, and an attractive setting. However, they also represent sources of fluvial flood risk in Enfield, posing a potential threat to life and property which needs to be pro-actively managed. The underlying pattern of geology and the effects of urbanisation mean that the borough is also susceptible to incidents of surface water and groundwater flooding.
8.5.2 Enfield's Strategic Flood Risk Assessment (SFRA) Level 1 (2008) and Surface Water Management Plan (SWMP) (2012) provide local evidence of all forms of flooding including fluvial, surface water, groundwater, sewers and reservoirs. For the purposes of the policies in this section, flood risk areas are defined as Flood Zones 2 and 3 (for fluvial flooding), and areas at risk from other sources of flooding identified in evidence including the SFRA and SWMP.
DMD 59 Avoiding and Reducing Flood Risk 1) New development must avoid and reduce the risk of flooding, and not increase the risks elsewhere. New development must:
Planning permission will only be granted for proposals which have addressed all sources of flood risk and would not be subject to, or result in unacceptable levels of flood risk on site or increase the level of flood risk to third parties. This policy should be read in conjunction with Core Strategy Policy 28. |
Justification and guidance on implementation
8.5.3 New development should be located appropriately to avoid risks of flooding as directed by the Core Strategy and NPPF. The policy criteria above will also ensure developments reduce the causes of flooding.
8.5.4 Up-to-date maps showing risk areas for fluvial flooding are provided in the SFRA and may be updated thereafter by the Environment Agency. Areas at risk from surface water, ground water flooding, and from other sources are shown in the SFRA and SWMP.
8.5.5 Two separate geology based datasets on indicative groundwater flood risk from Enfield's SFRA and SWMP have been combined to derive a map of groundwater flood risk areas for the borough. This map is provided in the Policies Map Document. The risks of groundwater flooding are considered to be low relative to fluvial and surface water flooding and should be managed accordingly.
DMD 60 Assessing Flood Risk 1) Requirements for a site specific Flood Risk Assessment Site specific Flood Risk Assessments will be required for the following:
These FRAs must: f. Where applicable, provide evidence so that the Council can assess whether the requirements of the sequential test of sites across the borough are met, and where an exception test is required, demonstrate that:
2) Additional requirements for non fluvial flooding
Developments at risk of flooding need to make sure they are safe and incorporate appropriate mitigation measures in line with DMD 62 'Flood Control and Mitigation Measures' and DMD 63 'Development adjacent to or affecting watercourses' and have regard to specific measures identified in the SFRA. This Policy should be read in conjunction with Core Strategy Policy 28. |
Justification and guidance on implementation
8.5.6 The NPPF requires site specific Flood Risk Assessments (FRAs) be carried out for developments proposed in flood risk areas. This policy refines this requirement to reflect evidence and recommendations in Enfield's SFRA and SWMP.
8.5.7 Applying the sequential test and exception tests is required by NPPF. This will help to direct development to the lowest risk areas unless there is a clear justification for an alternative higher risk location. The Core Strategy high level sequential test provides justification for steering new development towards the AAP strategic growth areas.
8.5.8 Where the Sequential Test shows that there are no suitable available alternative sites in lower flood risk areas and development is required, the sequential approach should be applied within the development site to locate the most vulnerable elements of a development in the lowest risk parts of the site.
8.5.9 As part of the Sustainable Drainage Strategy, developers will be required to demonstrate that there is sufficient wastewater infrastructure both on and off site to serve the development.
8.5.10 Developers should prepare FRAs in accordance with requirements and guidance set out in the NPPF, SFRA (Level 1 and 2 as appropriate) and the Appendix to this document.
DMD 61 Managing Surface Water A Drainage Strategy will be required for all developments to demonstrate how proposed measures manage surface water as close to its source as possible and follow the drainage hierarchy in the London Plan. All developments must maximise the use of and, where possible, retrofit Sustainable Drainage Systems (SuDS) which meet the following requirements: 1. Suitability
2. Quantity
3. Quality
4. Functionality
5. Other
The criteria above must be demonstrated through the submission of a site specific FRA, where one is required, or a Sustainable Design and Construction Statement. This Policy should be read in conjunction with Core Strategy Policy 28. |
Justification and guidance on implementation
8.5.11 Effective management of surface water will reduce the risk of flooding, pollution and other environmental damage.
8.5.12 Any development has the potential to increase the risk of flooding further down the catchment. Even minor developments, such as modifications to individual properties, contribute significantly to the overall run-off characteristics of a given catchment area when their cumulative effect is considered. Consequently, the Core Strategy and this policy require all developments to maximise the use of SuDS. All developments must also make every effort to retain permeable surfaces, flood storage and flow routes to mitigate possible increases in flood risks elsewhere. SuDS should be provided on site so that they are managed as part of that development unless there are practical reasons for not doing so in accordance with the following London Plan drainage hierarchy:
8.5.13 The selection of SuDS measures must be appropriate to the site and the nature of the proposed development and/or operations. Local geology, areas of sensitive groundwater supplies (such as Source Protection Zones), and the pollution potential of certain uses may constrain the types of SuDS that can be employed on particular sites. However, this does not mean that SuDS should not be implemented. Developers must use information on local conditions, including the SFRA, SWMP and the information held by other organisations, to inform/justify their selection of SuDs measures.
8.5.14 SuDS schemes can contribute towards meeting a number of wider sustainability policy objectives. Water quality can be improved if the SuDs include treatment phases, and in line with best practice, the number of treatment stages should correspond with the run-off pollution potential. SuDS measures can also provide opportunities to enhance local biodiversity and amenity, such as the use of green roofs, basins and ponds.
8.5.15 To be effective, SuDS need to be properly maintained. Maintenance issues can be simplified by keeping SuDS above ground. Examples of above ground SuDS features include basins and ponds, green roofs, permeable surfaces, water butts and swales. By keeping such features above ground, when problems do occur they are generally obvious and can be remedied simply using standard landscaping practice.
8.5.16 Further guidance on Sustainable Design and Construction Statements is given in the Appendix 3 to this document.
DMD 62 Flood Control and Mitigation Measures Development that increases flood risk to third parties or is not defined as safe in line with Enfield's Strategic Flood Risk Assessment (SFRA) will not be acceptable. All new developments at risk of flooding should be accompanied by appropriate flood mitigation measures. New development should:
Where the development is for essential infrastructure, the measures should ensure that the site is designed to remain operational when floods occur. The Council will refuse proposals which provide an unacceptable standard of safety. This Policy should be read in conjunction with Core Strategy Policy 28. |
Justification and guidance on implementation
8.5.17 Development should first be directed away from flood risk. Developers must apply DMD 59 'Avoiding and Reducing Flood Risk' in the first instance, and not just refer to this policy to justify the development.
8.5.18 In line with the SFRA, to be classed as ‘safe’, the development must:
8.5.19 Flood resilience is a design measure that reduces the damage to buildings from flooding. Examples of flood resilient design measures include raising electrical circuits and other services and using appropriate floor and wall coverings. Flood resistance measures aim to prevent flood waters from entering properties, examples include fitting flood-proof air brick covers and non-return valves to drainage systems.
8.5.20 The flood mitigation measures employed must have regard to any specific measures identified in SFRA (Levels 1 and 2) and the Local Flood Risk Management Strategy, and be carried out in accordance with the main messages in the Thames Region Catchment Flood Management Plan.
DMD 63 Protection and Improvement of Watercourses and Flood Defences 1. New development must make space for water and not harm the integrity of flood defences. New development should:
2. Development on any land required for current and future flood management, which would adversely affect the delivery of flood defence schemes, will be refused. 3. Development on or adjacent to watercourses must not:
A Water Framework Directive assessment will be required for some works on or adjacent to a watercourse. In these cases, the developer will need to contact the Environment Agency and provide information to demonstrate that the above requirements (2a-c) are met or, to otherwise justify the development. This Policy should be read in conjunction with Core Strategy policies 28 and 29. |
Justification and guidance on implementation
8.5.21 The protection of existing flood defences is important because the failure of these assets could have severe consequences and pose a risk to life and property. New development should therefore be set back from defences and watercourses 3 to ensure that there is space and access available to allow for future maintenance. Development should also be set back from watercourses to preserve their settings and to minimise the risks to the development. The set back distance applied to ordinary watercourses will be determined by having regard to the nature of the development and the type of ordinary watercourse
8.5.22 The naturalisation of watercourses releases the potential for additional waterflow and flood storage, and provides amenity and biodiversity value. Development should realise opportunities for de-culverting existing watercourses and there will be a general presumption against further culverting.
8.5.23 The Environment Agency will be consulted on applications within 8m of a main river. Therefore in addition to local evidence and strategies,development proposals in the vicinity of watercourses also need to ensure that they are compatible with the main messages and objectives of documents prepared by the Environment Agency, particularly the Lower Lee Flood Risk Management Strategy,River Basin Management Plan for the Thames River Basin (i.e. Developers should refer to the objectives for relevant watercourses in the RBMP including the following:
1 "Upper Lee Valley Decentralised Energy Network Pre Feasibility Study" Parsons Brinckerhoff (July 2011) for North London Strategic Alliance.
2 "Upper Lee Valley Decentralised Energy Network Feasibility Study" Parsons Brinckerhoff (August 2012) for North London Strategic Alliance.
3 For the purposes of this policy watercourses refers to main rivers and ordinary watercourses.
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