Draft Horsham District Local Plan 2019-2036

Chapter 9 Climate Change and Flooding (Key Questions)

The following issues have been identified that will be addressed through the policies in this document:

  • Development needs to be designed to be adaptable to the impacts of a changing climate and to reduce vulnerability to issues such as flood risk, drought and changing temperature patterns.
  • Renewable technologies should be incorporated into new developments, including district heating schemes or solar energy.
  • An increase in pressure for renewable energy provision may conflict with landscape and townscape character
  • A key mechanism to address climate change will be to ensure that new developments are built to high sustainability standards, to reduce the demand for energy and reduce emission of greenhouse gases. Reduction in the demand for transport should also be incorporated where possible to reduce the impacts of traffic on climate change.
  • Development will place increased pressure on water resources. Changing weather conditions as a result of climate change (such as hotter summers) may also increase demand for water.
  • Any development proposals will need to consider the capacity on existing wastewater treatment works and the ability of these sites to expand in the future.
  • Climate change has the potential to increase the area at risk of flooding. Development will need to be located away from areas at risk of flooding and incorporate measures to avoid increasing the risk of flooding downstream.
  • Development also has the potential to increase flood risk by increasing the speed and quality of run-off into rivers and streams. Development must incorporate appropriate flood attenuation measures to manage such runoff.

9.1 It is widely accepted that climate change is being generated by increasing levels of carbon dioxide (CO2) in the atmosphere. In Horsham District, these emissions arise from a range of sources, including homes, businesses and transport. Climate change will impact the District in a number of ways including drought, flooding and an increase in the number of heatwave events. These impacts have the potential to affect business and public health. There is therefore a need for the Horsham District Planning Framework to recognise the effects of climate change and consider ways the District can adapt to the changes already taking place.

9.2 Nationally the UK has committed to becoming net carbon zero by 2050. This has been reflected locally by the adoption of a Notice of Motion in June 2019. This committed the Council to the development and implementation of a range of measures that work towards a zero carbon target. Although positive steps to lower carbon emissions have been made, with carbon emissions for the District reducing by 32% between 2005 and 2017, this needs to continue. The need to mitigate and adapt to climate change is therefore a key objective of this plan. The largest sector for carbon emissions is transport, (46% of the total); with 30% for industry and commercial and 34% for homes. Carbon reduction will need to be delivered through a number of measures, including indirectly through providing more local employment and reducing commuting distances.

9.3 In order to demonstrate how proposals will minimise the impacts of and adapt to climate change, planning proposals will need to be accompanied by information proportionate to the scale of development proposed. These Statements should set out how the development has taken measures to mitigate and adapt to the effects of climate change; how the development has considered the energy hierarchy and heating and cooling hierarchy, if appropriate; and how sustainable design and construction measures have been incorporated into development design. The statements should also address how any potential flood risk will be mitigated, as set out in the policies within this plan. Positive weight will be given to low carbon and renewable energy schemes that have clear evidence of local community involvement. However, such schemes will also need to ensure that they do not have significant adverse effect on landscape character, biodiversity, heritage or cultural assets or amenity value.

Strategic Policy 37 - Climate Change

9.4 The impacts of climate change are predicted to increase over time, with winters getting warmer and wetter, while summers become hotter and drier. It is expected that there will be more extreme weather leading to impacts including intense rainfall, floods, heatwaves, droughts and increased risk of subsidence. These impacts will affect people’s lives, homes and businesses as well as essential services and supplies such as transport, hospitals, water supply and energy. There will also be significant impacts on biodiversity and the natural environment.

9.5 There is a need to ensure that new development seeks to reduce factors that contribute to climate change, and that new development is adapted to future climate change to make sure future communities can live, work, rest and play in a comfortable and secure environment in the face of inevitable climate change. Given the anticipated level of growth in the District, it is important that development takes place in a sustainable manner, incorporating climate change reduction and adaptation technologies and that these are flexible to accommodate technological advancements throughout the plan period. Buildings, services and infrastructure need to be able to cope easily with the impacts of climate change. Part of this ability to cope relates to ensuring that new development is designed to adapt to more intense rainfall, the possibility of flooding, heatwaves and droughts. The design of developments need to be more considerate to  matters such as shading, insulation and ventilation, surface water runoff and storage and the use of appropriate tree and other planting.

9.6 Planning can have a key role in shaping places to help minimise vulnerability and provide resilience to the effects of climate change. This policy is an overarching policy, designed to ensure the impacts of climate change are fully considered from the onset of early design and to ensure that development is future proofed and able to recover from extreme weather events such as flooding, drought and heatwaves.

9.7 There is an expectation that developers will demonstrate how they have incorporated measures to adapt to climate change into development design. In addition to this policy, reference should be made to transport policies, and minimise the need to travel, and contributing to the electric vehicle network.

Strategic Policy 37 - Climate Change

Carbon reduction

Development proposals are expected to include measures which contribute to achieving zero carbon. Major development proposals will be expected to attain a 19% reduction of the Dwelling Emission Rate when compared with the 2013 Edition of the 2010 Building Regulations (Part L) (equivalent to the code for sustainable homes level 4). Schemes will be expected to demonstrate how this target will be attained. The Council will be supportive of a range of measures to achieve this target, including but not limited to: 
  1. Influencing the behaviour of occupants to reduce energy use;
  2. Reducing the amount of energy used in construction and operation of new buildings, including through the materials used in construction;
  3. The use of decentralised, renewable and low carbon energy supply systems including solar panels and ground source heat pumps;
  4. Using patterns of development which reduce the need to travel, encourage walking and cycling and include good accessibility to public transport and other forms of sustainable transport; and
  5. Incorporating measures that reduce the amount of biodegradable waste sent to landfill.

Climate change adaptation

All major development must demonstrate how it has been designed to adapt to the impacts of climate change and reduce vulnerability, particularly in terms of flood risk, water supply and changes to the District's landscape. Such measures should include:
  1. Use of site layout. Wherever possible new buildings should be orientated to maximise the opportunities for both natural heating and ventilation and to reduce the exposure to wind and other elements;  
  2. Design measures to maximise resistance and resilience to climate change, for example through the use of solar shading, thermal mass, heating and ventilation, green and brown roofs and green walls;
  3. Green infrastructure and dual use Sustainable Urban Drainage Systems (SuDS) to help absorb heat, reduce surface water runoff, provide flood storage capacity and assist habitat migration; and
  4. Measures which promote the conservation of water and/or grey water recycling.

Strategic Policy 38 - Appropriate Energy Use

District Heating

9.8 Without mitigation, there is potential for future development in Horsham District to have a significant impact on the consumption of energy and resources, which in turn will contribute to climate change, including global heating. 

9.9 Electricity production in the UK is currently dominated by a centralised electricity generating system. Centralised electricity generating stations are not efficient: on average around 65% of the energy used to produce electricity is lost as heat before it even reaches consumers. If better use could be made of this waste heat, and the transmission distances reduced, there would be major benefits in tackling climate change and improving security of supply.  It is considered that decentralised energy systems such as combined heat and power can help address these issues – these systems are considerably more efficient.

9.10 This policy seeks to ensure that developments consider the most appropriate energy use as a means of improving efficiency into their design. There is an expectation that developments will be constructed to energy performance standards that push beyond Building Regulations and where this is not met on site, it is expected that there will be a contribution to a carbon offset fund in order to work towards achieving carbon neutrality.

9.11 The Planning and Energy Act 2008 allows local planning authorities to impose reasonable requirements for:

  1. a proportion of energy used in development in their area to be energy from renewable sources in the locality of the development;
  2. a proportion of energy used in development in their area to be low carbon energy from sources in the locality of the development;
  3. development in their area to comply with energy efficiency standards that exceed the energy requirements of building regulations.

9.12 At the current time, the Government are consulting on their intention to repeal part (c). Should this proceed, part (a) and (b) will remain. Therefore, in order help reduce carbon emissions all major development should incorporate renewable and low carbon energy production equipment to meet at least 10% of predicted energy requirements. Such energy generation could take the form of photovoltaic energy, solar-powered, heat pumps and geo-thermal water heating.

9.13 Although completed some time ago, the West Sussex Sustainable Energy Study 2009 provides a resource assessment of the capacity of each of various renewable technologies. As the District is a largely rural area with a number of areas of high landscape sensitivity, the study found that there were limited opportunities for energy installations which require extensive land areas such as large scale wind farms.

9.14 Given the relative lack of opportunities for large scale renewable and low carbon energy generation in Horsham district, the West Sussex Sustainable Energy Study recommended a hierarchical approach be applied to the use of energy and energy technologies such as combined heat and power. Using these hierarchies will ensure the lowest carbon outcomes are achieved in any given context.

9.15 The main focus of the policy is the provision of a hierarchy to ensure that development that comes forward is connected to the most efficient source of energy available. In addition, there will be a new requirement for all new strategic scale developments to combine heat and design into their master-planning. The aim of this is to ensure that the development mix, density and layout of large developments is optimal for connection to district heat networks. Designated Heat priority areas indicate the key locations in the District where there is the greatest potential to connect to localised heating sources.  This is particularly important given the suggestion by the Committee on Climate change that new homes should not be connected to the gas network by 2025.

9.16 The development of District heating networks in new developments will be encouraged. New development in Heat Priority Areas will be expected to maximise opportunities for the development of a District heating network which may include the incorporation of sites and buildings in areas where district heading has yet to be developed.

Renewable Energy

9.17 The development of renewable and low carbon energy is a key means of reducing the District's contribution to climate change. Renewable and low carbon energy can encompass a wide range of technologies including combined heat and power (CHP); combined cooling, heat and power (CCHP); district heating, energy from waste, wind (large and small scale), biomass, solar (thermal and photovoltaics) and heatpumps.

9.18 Due to the variations in the suitability, type and scale of energy resources which could be used throughout the District, a flexible approach to energy targets should be applied, in order to ensure opportunities for greater carbon savings are maximised where they exist, without placing undue pressure on areas where savings may not be technically or financially feasible.

9.19 The Renewable Energy Study identified the use of district heating including CHP and CCHP as a cost effective means of providing low carbon energy in identified Heat Priority Areas. Outside these areas the focus should be on other types of renewable and low carbon technologies such as solar thermal, photovoltaic and ground source heat pumps.

9.20 Support will be given to community initiatives which are used to deliver renewable and low carbon energy, especially when considered as part of a Neighbourhood Plan.

9.21 The evidence base supporting this plan (the West Sussex Sustainable Energy Study), identified limited capacity for wind turbine development due to the landscape constraints of the District. Any wind turbine proposals will be considered against the written Ministerial Statement concerning Energy and Climate Change, published on the 18th June 2015 or latest government guidance thereafter.

9.22 Renewable energy proposals will need to take into account the impact that they may have on protected landscapes. This includes the need to take into account views from protected landscapes to proposals which lie outside the South Downs National Park or High Weald AONB. Applicants should also refer to Policy 30 - Protected Landscapes.

Strategic Policy 38 -  Appropriate Energy Use

All new major development will be expected to incorporate renewable/low carbon energy production equipment to provide at least 10% of predicted energy requirements.   

Heating and Cooling

  1. In meeting the sustainability requirements of this plan, all domestic and non-domestic developments will be expected to comply with the heating / cooling hierarchy set out below;
    1. Connection to existing (C)CHP distribution networks
    2. Site wide renewable (C)CHP
    3. Site wide gas-fired (C)CHP
    4. Site wide renewable community heating/cooling
    5. Site wide gas-fired community heating/cooling
    6. Individual building renewable heating
    7. Individual building heating, with the exception of electric heating
  1. All new strategic developments and development located within Heat Priority Areas must incorporate combined heat and power into their master planning. Commercial and residential developments in Heat Priority Areas will be expected to connect to district heating networks where they exist or incorporate the necessary infrastructure for connection to future networks.
Energy Statements


  1. All applications for residential or commercial development must include an Energy Statement demonstrating how compliance with the Heating/ Cooling hierarchy has been achieved.  Horsham District Council will work proactively with applicants on major developments to ensure these requirements are met.
  2. Where compliance with the Heating/ Cooling hierarchy has not been possible, a contribution into a Carbon Offset fund will be sought to work towards achieving carbon neutrality, unless it can be demonstrated that the scheme is not suitable, feasible or viable for this form of energy provision.

Renewable Energy Schemes

Stand-alone renewable energy schemes will be supported where they do not conflict with other policies in this plan. Community initiatives which seek to deliver renewable and low carbon energy will be encouraged.

Policy 39 - Sustainable Design and Construction

9.23 Sustainable design has a key role to play in mitigating the environmental impact of new development, at the time of construction and in the future. This policy seeks to ensure new development is designed and constructed in a way that minimises its impact on the environment, however it now also includes the requirement that ‘Non-domestic floorspace must achieve a minimum standard of BREEAM ‘Very Good’ with a specific focus on water efficiency’.

9.24 Water is a key resource in the District and has a fundamental part to play in contributing to the economy, ecosystems and overall health of the District's population. Much of the South East has now been designated as an ‘area of serious water stress’ by the Environment Agency. This is something which is recognised in the Water Resource Management Plans (WRMP) of the two water companies operating in the District; Southern Water and Thames Water. Climate change has the potential to place further stress on this supply, causing longer periods of drought and reducing river flow which could impact the quality of the District's rivers. On this basis , Horsham District Council  propose that all new housing should meet the tighter level of water efficiency in line with Southern Water’s ‘Target 100’ objective for reducing water use to 100 litres per person per day by 2040 as set out in its Water Resources Management Plan 2020-2070 document.

9.25 The Building Research Establishment Environmental Assessment Method (BREEAM) is an accredited, independent method for assessing the environmental performance of non-domestic development. Non domestic development should be assessed against the BREEAM standard and all new non-domestic development should achieve the level ‘Very Good’ under this standard. The Council will require the BREEAM standard to be verified by an independent assessor at the applicant or developer’s cost.

9.26 The policy also seeks to deliver flexibility in development design to enable buildings to be easily adapted, either to respond to a changing climate or to reflect changing lifestyle needs. Where traditional or historic buildings are retrofitted to reduce emissions, applicants are advised to refer to Energy Efficiency and Historic Buildings (or any relevant updates) published by Historic England.

Policy 39 - Sustainable Design and Construction


Proposals must seek to improve the sustainability of development. To deliver sustainable design, development should incorporate the following measures where appropriate according to the type of development and location:
  1. Development should minimise construction and demolition waste and utilise recycled and low-impact materials;
  2. New ‘Non-domestic floorspace must achieve a minimum standard of BREEAM ‘Very Good’ with a specific focus on water efficiency’.
  3. All development should maximise energy efficiency and integrate the use of decentralised, renewable and low carbon energy;
  4. All new residential development must limit water use to 100 litres/person/day;
  5. Development should be designed to encourage walking, cycling, cycle storage and accessibility to sustainable forms of transport including the provision of electric vehicle charge points;
  6. Buildings should be flexible to allow future modification of use or layout, facilitating future adaptation, refurbishment and retrofitting;
  7. Development should incorporate measures which enhance the biodiversity value of development.

New homes and workplaces should include the provision of high-speed broadband access and enable provision of future technologies.

All new development will be required to provide satisfactory arrangements for the storage of refuse and recyclable materials as an integral part of design.

Historic Buildings


The retrofitting of traditional and historic buildings to reduce emissions must be done appropriately.

Strategic Policy 40 - Flooding

9.27 This policy is designed to ensure development adapts to the likely changes in the future climate and flood risk is not increased. It also accords with the ‘Wilder Horsham’ objective to maximise opportunities from protecting and enhancing wildlife to tackling climate change and to reduce the impacts of a changing climate.

9.28 Flooding is a natural process that can happen at any time, in a variety of locations. It can arise from rivers, the sea, directly from rainfall on the ground’s surface or from rising groundwater levels, overwhelmed sewers and drainage systems. In the future the risk of flooding is likely to increase as a result of climate change, which is predicted to bring more intense rainfall events that could lead to more frequent flooding events occurring and new areas becoming vulnerable to flooding.

9.29 The Council has undertaken a Strategic Flood Risk Assessment (SFRA) which covers the Adur and Arun catchment areas, and with neighbouring local authorities as part of a Gatwick Sub Region Water Cycle Study. The recommendations of the revised 2019 SFRA and Water Cycle Study have informed this policy to ensure flood risk is appropriately managed in the district.

9.30 Approximately 6% of the District is classed as flood zone 3a or 3b which is considered the 'functional floodplain'. Development activity should be located away from these areas and in addition will need to undertake site specific flood risk assessments (FRAs) that

  • Meet the recommendations of the revised 2019 SFRA
  • Assess the risk of all forms of flooding
  • Investigate groundwater flooding in detail in the south of the district or where a site is located in groundwater emergence zone
  • Identify options for mitigation

9.31 The impact that development can have on flood risk as a result of increased run-off or changing drainage patterns must also be considered. To ensure development does not increase flood risk, developments will be required to incorporate measures such as Sustainable Drainage Systems (SuDS) to help manage flood risk. SuDS manage surface water and groundwater sustainably and help to reduce flood risk, minimise diffuse pollution, maintain or restore natural flow regimes, improve water resources and enhance amenity. It is important SuDS are appropriate in scale and location. They should be incorporated into the Council's Green Infrastructure network where appropriate.

9.32 The West Sussex County Council Local Flood Risk Management Strategy identifies the responsibilities for flooding within the county and enables a range of organisations to work together to improve the management of flood risk. Early discussion with the appropriate flood risk management authority on SuDS for appropriate management techniques will be required.

9.33 Where appropriate, development will be encouraged to look for ways to improve water quality to ensure the objectives of the Water Framework Directive can be met.

Strategic Policy 40 - Flooding

  1. Development proposals will follow a sequential approach to flood risk management, where priority is given to development sites with the lowest risk of flooding and making required development safe without increasing flood risk elsewhere. Development proposals will;  
    1. consider flood risk at an early stage in deciding the layout and design of the site.
    2. take a sequential approach to ensure most vulnerable uses are placed in lowest risk areas.
    3. avoid development on the functional floodplain (Flood Zone 3b) except for water-compatible uses and essential infrastructure.
    4. only be acceptable in Flood Zone 2 and 3 following completion of a sequential test and exceptions test if necessary, using a 1 in 100 annual probability flood level including an appropriate allowance for climate change.
    5. not result in a net loss of flood storage capacity and not adversely affect flood routing and thereby increase flood risk elsewhere.
    6. require a site-specific Flood Risk Assessment for all developments over 1 hectare in Flood Zone 1 and all proposals in Flood Zone 2 and 3.
  2. Comply with the tests and recommendations set out in the Horsham District Strategic Flood Risk Assessment (SFRA).
  3. Where there is the potential to increase flood risk, proposals must incorporate the use of sustainable drainage systems (SuDS) where technically feasible, or incorporate water management measures which reduce the risk of flooding and ensure flood risk is not increased elsewhere.
  4. Consider the vulnerability and importance of local ecological resources such as water quality and biodiversity when determining the suitability of SuDS. New development should undertake more detailed assessments to consider the most appropriate SuDS methods for each site. Consideration should also be given to amenity value and green infrastructure.
  5. Utilise drainage techniques that mimic natural drainage patterns and manage surface water as close to the source as possible. This will be required where technically feasible.
  6. Be in accordance with the objective of the Water Framework Directive, and accord with the findings of the Gatwick Sub Region Water Cycle Study in order to maintain water quality and water availability in rivers and wetlands and wastewater treatment requirements.


  • Do you agree with the draft policies in this section?
  • If not, what changes would you suggest?