Draft SEA Determination and Screening Statement March 2021

Our Dry Weather Plan

South East Water’s 2021 draft drought plan

Appendix H: Draft SEA determination and Screening Statement March 2021

South East Water Rocfort Road Snodland Kent ME6 5AH

Draft SEA determination and Screening Statement | 2021

Contents

1. Introduction 4

2. The Drought Plan and SEA 5 2.1 Background on water resource planning and the Drought Plan 5 2.2 SEA Regulations 7 2.3 The need for SEA of the Drought Plan 7

3. SEA screening assessment 10 3.1 Description of Drought Plan actions 10 3.1.1 Timing of actions 12 3.2 SEA screening methodology 12 3.2.1 Initial consideration 13 3.2.2 Screening assessment 13 3.2.3 Evidence base 13 3.3 Consideration of SEA topics 14 3.4 Supporting environmental assessments 17 3.5 Screening assessment: demand side actions 17 3.6 Screening assessment: supply side actions 18 3.6.1 Surface water options 21 3.6.2 River Ouse (winter period) drought permit/order 21 3.6.3 River Ouse (summer period) drought permit/order 25 3.6.4 River Cuckmere (winter period) drought permit/order 30 3.6.5 Groundwater options 33 3.6.6 Chasewood drought permit/order 34 3.6.7 Southlands and Oaklands drought permit/order 35 3.6.8 Balcombe drought permit/order 37 3.6.9 Hackenden drought permit/order 39 3.6.10 Halling No.8 drought permit/order 40 3.7 Screening assessment summary 43 3.8 Cumulative effects 43

4. Conclusions 46

References 50

Page 2 of 59

Draft SEA determination and Screening Statement | 2021

Appendix A: Figures 51

Role/Task Person/Date

Data item/measure producer Emma Mungo Jacobs

Data item checker Ros Vincent Jacobs

Data item reviewer Sam Pottier South East Water

Jon Barnes Jacobs

Sign off / approval Lee Dance (incl by who and when) South East Water 26 March 2021

Greg Tate Jacobs 26 March 2021

Page 3 of 59

1. Introduction

This draft Strategic Environmental Assessment (SEA) determination and screening statement sets out the basis for considering the requirement for undertaking SEA of South East Water’s (SEW) draft Drought Plan 2021. The draft Drought Plan 2021 is based on the published 2019 Drought Plan and includes minor updates to this plan.

This report is structured as follows:

Section 2 sets out the regulatory requirements and recently published guidelines and how these are considered in terms of how they are applicable to the draft Drought Plan 2021. The general nature of the plan is outlined and the plan is taken through the SEA screening decision points and the screening criteria are set out.

Section 3 describes the specific proposals in the draft Drought Plan relevant for consideration and the SEA screening methodology and covers:

 focusing the screening assessment considering the proposed Drought Plan actions and the relevant SEA topic areas in terms of identifying potential for significant effects and need for screening assessment

 screening for each individual action based on a review of information available, including results from monitoring and specific action environmental assessments undertaken to identify potential impacts and consider the mitigation measures required and likelihood of significant adverse environmental effects

 assessment of in-combination and cumulative effects of the actions to determine if these could result in significant adverse environmental effects.

Section 4 summaries the assessment findings and sets out the overall conclusions against the screening criteria. Additional measures for inclusion in the Drought Plan are identified and the draft determination and screening statement on the requirement for SEA is provided.

2. The Drought Plan and SEA

2.1 Background on water resource planning and the Drought Plan We have set out the overarching aim underpinning our water resource planning as: “To provide today’s public water service and create tomorrow’s water supply solutions, fairly and responsibly, working with others to help society and the environment to thrive.”

This purpose guides all our actions and decisions alongside our statutory duty to provide water for customers. In doing so we must make sure we have a robust system to ensure water resources are managed efficiently and effectively to meet the needs of our customers.

Our overall approach to managing water resources is set out in our water resources management plan 2019 (WRMP19), approved by Department for Environment, Food & Rural Affairs (Defra) in August 2019. The WRMP19 sets out our plans to provide a secure supply for customers from 2020 to 2080. The water resource management plans have a five year cycle and the next WRMP will be produced in 2024.

While the WRMP19 and future WRMPs aim to address long-term water demand, we know that different weather patterns may lead to a short-term supply demand challenge. This could be through a shortage of rainfall, or heatwave conditions, both of which can impact the availability of water, or the demand for water. As a responsible business it is important we are prepared for these challenges.

A dry weather and drought plan is therefore prepared as an operational guide. It builds on our last drought plan published in 2019. In preparing this we have taken into account applicable new statutory requirements including the Water Company Drought Plan guideline, December 2020 (Version 1.2)1 and the Environment Agency 2017 National Framework for Drought.2

Figure 2.1 shows the flow of the overall tactical plan with the sequence of key elements which will form our dry weather and drought plan.

1 Environment Agency (2020). Water Company Drought Plan guideline, December 2020 (Version 1.2). 2 Environment Agency (2017). National Framework for Drought. 5

Figure 2.1: Key elements of each section of the proposed 2021 draft drought plan

TACTICAL PLAN

INTRODUCTION ENGAGEMENT TRIGGERS ACTIONS COMMUNICATIONS ENVIRONMENT END OF ADDITIONAL DROUGHT INFORMATION

Area of severe Customers & Drought levels Agile plan Agile communications Responsibility to Review scale of Drought water stress stakeholders protect & environmental Management enhance impact & actions Team environment

Meet customer Statutory & non- Groundwater & Target most Drought Environment Stop actions that Agreements and needs statutory reservoir at-risk Communications Plan Agency Drought have greatest Arrangements consultees levels, recharge resources Planning impact first & demand guidance

Protect Environmental Red, Amber, Reduce High- profile media Environmental Monitor resources Regional environment Scrutiny Group Green system demand campaign assessments Collaboration

Links to longer- Regional 22 trigger sites Supply side Encourage water Heritage Some actions to Alignment with term water collaboration Actions efficiency Environmental remain until Environment resources plans Records conditions are Agency local normal area drought plans

Easy to follow Staff workshops Drought matrix Drought Change customer Monitor and Environmental Links with plan assessment Permits & behaviour measure impact monitoring WRMP19 and Drought & assessment WRMP24 Orders

Regulatory Trade Override trigger Temporary National Drought Baseline Communications Links with other requirements organisations for bulk supplies Use Bans & Group monitoring and & consultation plans Non mitigation continue Essential Use Bans

Feedback Communities Drought Inter- Partnerships and joint Conservation Internal review Compensation welcome! modelling & company messaging legislation & arrangements testing transfers regulations

Communications Multi-sector Monitoring and Post drought Lessons learnt strategy solutions evaluation monitoring & & update plans restoration

2.2 SEA Regulations SEA is a statutory requirement in the UK following the adoption of Directive 2001/42/EC (the SEA Directive) on the assessment of effects of certain plans and programmes on the environment. The Directive was transposed into national legislation by The Environmental Assessment of Plans and Programmes Regulations 2004 (referred to as the SEA Regulations)3.

The range of environmental and social issues to be included in an SEA is set out in the SEA Regulations, and includes biodiversity, population, human health, fauna, flora, soil, water, air, climatic factors, material assets, cultural heritage, and landscape.

2.3 The need for SEA of the Drought Plan Government SEA guidance sets out the stages of the SEA process4. The water industry (UKWIR) guidance on environmental assessment for WRMPs and Drought Plans was published in 2021 and covers the process for determining the requirement for SEA5 and includes guidance on screening drought plans for SEA. The latest Drought Plan Guideline (2020) also includes recommendations for the application of SEA to water company drought plans. These guidance documents and regulations have all informed the consideration of the requirement for SEA for our Draft Drought Plan 2021.

The Drought Plan is a statutory plan with a formal adoption process and is therefore a qualifying plan under the SEA regulations. The key questions for screening as set out in the ODPM guide are

‘’Article 3(2) which makes SEA mandatory for plans and programmes: a) which are prepared for agriculture, forestry, fisheries, energy, industry, transport, waste management, water management, telecommunications, tourism, town and country planning or land use and which set the framework for future development consent for projects listed in Annexes I and II to the Environmental Impact assessment (EIA) Directive (85/337/EEC); or b) which, in view of the likely effect on sites, have been determined to require an assessment pursuant to Article 6 or 7 of the Habitats Directive (92/43/EEC).

Habitat Regulations Assessment (HRA) stage 1 screening was undertaken for the 2019 Drought Plan to demonstrate that there will be no significant effects on European sites for any of the eight drought permits/orders either on their own or in combination. There are no material changes to the 2021 Drought Plan proposals or HRA methodology that will change this conclusion.

3 The Environmental Assessment of Plans and Programmes Regulations (2004) (Statutory Instrument 2004 No. 1633) apply to any plan or programme which relates solely or in part to England. 4 ODMP, A Practical Guide to the Strategic Environmental Assessment Directive (2005) 5 UKWIR, Environmental Assessment Guidance for Water Resource Management Plans and Drought Plans (2021). Report Ref 21/WR/02/15 7

The key question is therefore whether the Drought Plan sets the framework for future development consents. It is noted that where any need for investment in infrastructure for water supply potentially requiring development consent is identified to meet demand in dry weather or drought conditions this will be addressed as options through the WRMP and regional plan, and subject to SEA.

The Drought Plan includes potential for drought orders and permits for which environmental assessment are prepared but these are not subject to EIA planning regulations. The ODPM guide notes that ‘’European Commission guidance6 (paragraph 3.23) states that plans and programmes which set the framework for future development consent of projects would normally contain ‘criteria or conditions which guide the way a consenting authority decides an application for development consent’. Development consent is defined in the EIA Directive as “the decision of the competent authority or authorities which entitled the developer to proceed with the project” (Article 1(2) of the EIA Directive)’’.

Under Article 3(4), environmental assessment is required for certain categories of plans and programmes only where they are determined to be likely to have significant environmental effects. Plans and programmes in these categories include: ‘plans and programmes, other than those referred to in article 2, which set the framework for future development consent of projects, are likely to have significant environmental effects determine whether plans or programmes referred to in paragraphs 3 and 4 are likely to have significant environmental effects’

The ODPM guide states that the responsible authorities must carry out screening to determine whether plans or programmes of the types covered by 3(4) are likely to have significant environmental effects, and hence whether SEA is required under the Directive. Annex II of the Directive lists criteria for determining the likely significance of the environmental effects of plans or programmes (Table 2.1). The responsible authority must make its conclusions on a determination available to the public, including reasons for not requiring SEA. It is also a requirement that when forming a view on whether SEA is needed in these cases, the responsible Authorities must consult with the statutory consultees.

Table 2.1: Key SEA screening criteria listed in Annex II of the SEA Directive

Plan characteristics

 the degree to which the plan or programme sets a framework for projects and other activities, either with regard to the location, nature, size and operating conditions or by allocating resources.

 the degree to which the plan or programme influences other plans and programmes including those in a hierarchy.

 the relevance of the plan or programme for the integration of environmental considerations in particular with a view to promoting sustainable development.

6 European Commission (2003). Implementation of Directive 2001/42/EC on the Assessment of the Effects of Certain Plans and Programmes on the Environment. Commission of the European Communities, Brussels 8

 environmental problems relevant to the plan or programme.

 the relevance of the plan or programme for the implementation of [European] Community legislation on the environment (for example, plans and programmes linked to waste management or water protection).

Effects and area characteristics:

 the probability, duration, frequency and reversibility of the effects

 the cumulative nature of the effects

 the transboundary nature of the effects

 the risks to human health or the environment (for example, due to accidents)

 the magnitude and spatial extent of the effects (geographical area and size of the population likely to be affected)

 the value and vulnerability of the area likely to be affected due to special natural characteristics or cultural heritage

 exceeded environmental quality standards or limit values of intensive land-use

 the effects on areas or landscapes which have a recognised national, Community or international protection status.

UKWIR 2021 guidance notes that while there is no clear case law on the definition of development consent in the SEA context there is case law on ‘development consent’ not being confined to meaning planning permission and other types of decisions and consents could constitute development consent. However, the UKWIR guidance also acknowledges that this is not clear cut. We are therefore taking a precautionary approach to screening and will consider whether the Drought Plan proposals are likely to have significant environmental effects.

For the previous Drought Plan 2019 we considered the need for SEA, but took the view that since the Drought Plan is a temporary operational plan, it did not set a framework for future development consent of projects within Annexes I and II to the EIA Directive and did not meet the criteria for significant effects on the environment.

The proposed draft Drought Plan 2021 updates the 2019 Drought Plan taking account information on baseline environment from ongoing monitoring, as well as guidance and policy development and WRMP19. Although no material changes are to be made to the measures included, we have decided to undertake SEA screening to allow a full consideration against SEA regulatory requirements in relation to potential for likely significant environmental effects.

3. SEA screening assessment

3.1 Description of Drought Plan actions The Drought Plan actions are summarised in Table 3.1. Further details of the options are provided in Section 3 of the Drought Plan.

Table 3.1: Summary of Drought Plan actions

Demand-side actions

DAPD1 Water Programmes of demand management and customer education are conservation accelerated and supplemented. Customers will be made aware of campaigns and calls concerns of impending drought and asked to conserve water. for voluntary restraint

DAPD2 Operational Addressing leakage, initiating pressure management, and reviewing water works to reduce conservation schemes (enhancement of measures already being carried demand out).

Restrictions on activities under 11 categories including a ban on hosepipe DAPD3 Temporary use use for watering a garden/plants, washing a private motor vehicle or bans leisure boat, filling a swimming or paddling pool or pond, cleaning windows and outdoor areas.

As set out by the Drought Direction 11 there is a range of water-use activities that may be prohibited with the application of a drought order. (these do not overlap with the temporary use ban and generally apply to non-domestic purposes. This includes a ban on watering outdoor plants on DAPD4 Restrictions on commercial premises, filling a non-domestic swimming pool or pond, uses of water through cleaning any vehicle, boat, aircraft, cleaning non-domestic premises, and a Drought Order suppressing dust.

The drought order would be applied for in two phases, with some concessions being made in the first and the latter phase thereby removing these restrictions.

Supply-side actions

DAPS1a Optimisation of existing sources DAPS1 Operational works During a developing drought the first step would be to review the potential effects of increased pressure on resources on the local supply regime.

Network efficiency, non-essential maintenance programmes to reduce demand.

DAPS2 Infrastructural Infrastructural connectivity and source improvements (DAPS2) and connectivity and disused sources (DAPS3) source improvements During a developing drought, we would undertake a new review process to see if any other options linked to acceleration of planned schemes would also be feasible (DAPS2). We would also seek to identify any sources that have recently become disused or reduced in output. If an abstraction licence is held, they could be quickly brought back into supply (DAPS3).

The following sources that were listed in the 2013 drought plan remain options that could potentially be brought forward:

 two sources where existing schemes could be developed, and abstraction increased (Southlands and Oaklands, and Halling No.8); and,  three disused sources (Hackenden, Chasewood, and Balcombe) which potentially could be re-commissioned. The reasons for their DAPS3 Reinstate disuse typically were poor yield or inadequate treatment facilities to disused sources (for treat poor water quality. which South East During a moderate drought, all feasible options under DAPS2 and DAPS3 Water holds an would be fully developed into schemes. This would require detailed design abstraction licence) work and relevant planning and environmental assessments, detailed discussion with the Environment Agency and then application for abstraction licences.

The Southlands and Oaklands scheme, Halling No.8 and three disused sources that have been identified during the preparation of the drought plan all require drought permit/order applications to revise or provide for new abstraction licences.

Any new options identified under DAPS2 may require a change in / or a new abstraction licence. A drought order would need to be applied for because they would have not been identified upfront in our drought plan.

DAPS4 Seek extension Shared resources and bulk transfer agreements (DAPS4 agree to existing bulk extensions, and DAPS5 new agreements) supplies above existing agreements We have a number of bulk supply and shared resource agreements already in place with neighbouring companies Southern Water Services DAPS5 Consider and Affinity Water Inter-company transfers play an important role in options for new bulk maintaining a balance between supply and demand across the South supplies and progress East, with bulk supplies making up eight per cent of our current supply if feasible alone.

Drought permits can only authorise a water undertaker to take water from specified sources or modify or suspend restrictions or obligations to which that undertaker is subject; relating to the (existing) taking of water from any DAPS6/7 drought source i.e. they act to increase available supplies. permit/order Drought orders may go further than drought permits. They can deal with applications discharges of water, abstractions and discharges by people other than the undertaker affected, supply, filtration and treatment obligations. As mentioned in Section 3.1.5 they can also allow water undertakers to prohibit or limit particular uses of water.

DAPS8 Emergency Review the Emergency Plan and put plan in place to prepare for planning procedures activation. Communication with stakeholders including neighbouring water for a drought companies and Local Authorities.

DAPS9 Potentially Under DAPS9 the water undertaker would have complete discretion on the damaging uses of water that may be prohibited or limited, and it can authorise supply environmental drought by stand-pipes, rota cuts or the use of water tanks. These are extreme orders (supply-side), actions and by this stage it would be anticipated that the drought situation and emergency would have to be recognised nationally by Government for these actions to drought orders be introduced and implemented. Should only be required in a very extreme (demand-side) drought.

3.1.1 Timing of actions During the escalation of a drought, the approach is to implement demand saving actions first and then prioritise the use of supply actions with the least associated environmental impact. The timing and phasing of putting actions into place is described in Section 3 of the Drought Plan. There is a need for flexibility in how actions are applied given the variable nature of drought scenarios and the effects of certain actions at different times of the year.

3.2 SEA screening methodology This Screening report has considered the SEA topics as set out in Schedule 2 of The Environmental Assessment of Plans and Programmes Regulations 2004. The definition of topics aligns with that used in the SEA for the WRMP (see topic definition in Section 5) and includes:

 population and human health  material assets (including transport infrastructure, water supply infrastructure, recreational assets (e.g. Public Rights of Way, fishing, minerals, agriculture, resources materials and waste)  biodiversity, flora and fauna  landscape  air  water (including water resources and quantity, water quality, flooding and flood risk) 12

 climate change  cultural heritage  soils and geology. There is no consideration of beneficial effects as these would not normally influence the decision about whether an option should be rejected at this early stage. For the purposes of this report the term ‘significant effect’ is therefore interpreted to only relate to adverse effects. To determine if the adverse effects are “significant”, the assessment takes account of the specific criteria as outlined in Table 2.1.

Given the geographical scale and nature of the Drought Plan Actions there are no pathways to effects on receptors in another country and therefore transboundary effects are not considered in this assessment.

3.2.1 Initial consideration The Drought Plan actions were firstly considered against each SEA topic in relation to the criteria set out in Annex II of the SEA Directive. This initial step was taken using a precautionary approach and where there was any uncertainty relating to possible effects, a topic was progressed to the screening assessment stage.

3.2.2 Screening assessment For Drought Plan actions requiring further consideration, a high-level assessment was carried out. This assessment was informed by the wide evidence base which was collated and reviewed in relation to each option (see Section 3.2.3). The assessment considered the potential for significant environmental effects and the suitability and adequacy of proposed mitigation. A decision on significance was made based on professional judgement, taking into account the quality of available evidence and the confidence in the baseline information. Any remaining uncertainties are clearly stated.

The assessment also considers the potential for cumulative effects as a result of implementing Drought Plan actions.

3.2.3 Evidence base The SEA screening assessment is predominantly informed by the numerous studies and assessments that have been prepared as part of the development of the Drought Plan. In addition, publicly available information has been gathered to complement the existing data sources. The evidence base includes:

 Drought Plan 2018 – 2023 (South East Water, 2021) including the following key appendices: o Appendix J: Draft Drought Permit/Order Applications o Appendix K: Identification of priority locations and potentially suitable designs for eel passes in the River Ouse, Sussex o Appendix L: Assessment of effects on SSSIs. o Appendix M: Habitats Regulations Assessment (HRA) o Appendix N: Water Framework Directive (WFD) Assessment o Appendix S: Maps showing locations of drought permit options  Invasive Non-Native Species assessment (INNS) produced to support the WFD Compliance Assessment. 13

 Water Resource Management Plan 2020 to 2080 including the SEA Environmental report (South East Water, 2019).  Multi-Agency Geographic Information for the Countryside (MAGIC, 2021).  Catchment Data Explorer (Environment Agency, 2021).

3.3 Consideration of SEA topics Each demand and supply side Drought Plan management action was first assessed as to whether there was a requirement to consider effects in relation to SEA topics (i.e. where there may be likely significant effects). The assessment is provided in Table 3.2.

Key

No further consideration required

Consideration required

Effects assessed elsewhere

Table 3.2: Consideration of Drought Plan Actions in relation to SEA topics (note: topics where consideration is required are shown in dark grey)

Comments

ral heritage ral

fauna

Population and human health Materialassets Biodiversity, flora and Landscape Air Climate change Water Cultu Soils and geology

Demand-side actions

DAPD1 Water conservation campaigns Voluntary requests for minor changes to behaviour are unlikely to lead to significant effects on the population. No pathways to effects on and calls for voluntary restraint other topics/receptors.

DAPD2 Operational works to reduce The enhancement of measures already being carried out is unlikely to lead to significant effects for any topics/receptors. demand

A temporary use ban would have a small impact on households and some businesses. Whilst inconvenient this is unlikely to lead to DAPD3 Temporary use bans significant effects on health and wellbeing. No pathways to effects on other topics/receptors.

DAPD4 Restrictions on uses of water Restrictions would impact people’s daily lives and businesses that rely on water. Potential for significant effects on population and human through a Drought Order health.

Supply-side actions

DAPS1 Operational works Changes to existing permitted activities would not result in significant effects.

This action relates to groundwater options to improve/reinstate existing schemes at Southlands and Oaklands, and Halling No.8 (see DAPS2 Infrastructural connectivity and Section 3.6 for more details). Assuming all infrastructure is in place there remains potential for significant effects on biodiversity, water source improvements and cultural heritage. Slight changes in water taste for some customers is unlikely to result in significant effects. Given the scale and nature of the options there are no significant effects on air quality.

This action relates to three disused sources (Hackenden, Chasewood, and Balcombe) which potentially could be re-commissioned. DAPS3 Reinstate disused sources (for Assuming all infrastructure is in place there remains potential for significant effects on biodiversity and water. Slight changes in water which South East Water holds an taste for some customers is unlikely to result in significant effects. Given the scale and nature of the options there are no significant abstraction licence) effects on air quality.

The effects of utilising of bulk supplies above existing agreements have been considered within the SEA of the South East Water WRMP DAPS4 Seek extension to existing bulk and within the WRMPs of donor companies. Further environmental assessments would be required as part of the agreement with the supplies above existing agreements donor company during a drought event if a feasible option is identified.

This action relates to new agreements to utilise shared resources or for bulk transfer of water. It is assumed that the water would be abstracted within an existing abstraction licence (or extended by the use of drought permits/orders). The effects of utilising shared DAPS5 Consider options for new bulk resources or for bulk transfer of water have been considered within the SEA of the South East Water WRMP and within the WRMPs of supplies and progress if feasible donor companies. Further environmental assessments would be required as part of the agreement with the donor company during a drought event if a feasible option is identified.

Comments

ral heritage ral

fauna

Population and human health Materialassets Biodiversity, flora and Landscape Air Climate change Water Cultu Soils and geology

Both surface water and groundwater drought permit/order applications could result in significant effects on biodiversity and water, and surface water options may also affect population and human health. The effects of drought on landscape would be noticeable, such as the exposure of previously submerged marginal features, dieback of vegetation and potentially dry channels, but these effects would be only be made slightly worse by the drought permit/order compared to the baseline and would not therefore be significant. DAPS6/7 drought permit/order In a similar manner there would be reduced water levels at historical structures on the river potentially causing them to dry out. These applications effects would be temporary and are unlikely to result in significant damage to cultural heritage assets as a result of implementation of a drought permit/order. Archaeological assets would not be affected by additional abstraction of surface water but could be affected by groundwater options at Southlands and Oaklands, and Halling No.8.

Given the scale and nature of the options there are no significant effects on air quality.

DAPS8 Emergency planning procedures This action only involves planning and there are no pathways to effects for any topics/receptors. for a drought

Under DAPS9 the water undertaker would have complete discretion on the uses of water that may be prohibited or limited, and it can authorise supply by stand-pipes, rota cuts or the use of water tanks.

People and businesses are likely to be affected by these actions for a short duration. There is also potential for significant effects on biodiversity and water, as further abstraction would exacerbate the effects of the drought. Actions may require transportation of water which could have potential effects on local air quality and may result in the emission of greenhouses gases which could contribute to climate change. In respect of HRA legislation there may be a need to provide evidence that there are no less damaging options available and to make a case for imperative reasons of overriding public interest. The effects on European designated sites as well as on water- dependent SSSIs would be considered in consultation with Natural England.

DAPS9 Potentially damaging The effects on waterbodies would be temporary and the WFD allows for a temporary deterioration in status in certain circumstances such environmental drought orders (relates to as prolonged droughts which could not have been reasonably have been planned for and prevented (Regulation 18). Advice from the supply-side only) Environment Agency would be sought to meet any requirements for mitigation.

Effects on cultural heritage and landscape would also be considered if abstraction is increased beyond the licenced quantities and consultation with the relevant authorities and advisors would be sought.

Whilst there is potential for effects on many receptors, there is robust planning and mitigation in place to prevent the need for this action to be taken. DAPS9 would only be required in a worse than 1:500 year drought (severe drought), and at a time when the Government has declared a national emergency. The Drought Plan includes an ‘Extreme Drought Action Plan’ which identifies alternatives to stand pipes and rota cuts. These alternatives would also be subject to environmental assessment and consultation with regulators regarding the suitability of alternatives. Given the probability, duration and frequency of DAPS9 being required and the mitigation in place to avoid the most damaging elements, this action is not considered further in this assessment.

3.4 Supporting environmental assessments There are links between the SEA process and other environmental assessment processes which are subject to specific legislation. The Drought Plan has been subject to Habitats Regulations Assessment (HRA) and a Water Framework Directive (WFD) Compliance Assessment has been carried out. The findings of these studies are summarised below.

The HRA screening assessment considered a number of European Designated sites downstream of or within 5km of the Drought Permit sites. Overall it has been determined that there are no mechanisms by which potential hazards arising from drought permit use (e.g. flow, water level, flooding, water chemistry or habitat loss) could have a likely significant effect on any of the European sites.

In combination impacts were considered during these assessment processes. In total there are three surface water abstractions and seven groundwater potential abstractions. Of these sources, none are considered to have direct or indirect impact on any European sites.

The WFD assessment concluded that all of the Drought Plan actions have a low risk of deterioration of WFD objectives, with the exception of the River Ouse summer permit which is considered to have a medium risk. The impact of a reduction in freshwater flows, as a direct result of the proposed drought permit/order, could increase the upstream presence of the saline wedge in the River Ouse during high spring tides. The likelihood of having no rain to flush the system will increase risk during the summer months. The WFD assessment outlined mitigation measures at specific locations which would minimise the risk of deterioration.

An assessment regarding the risk of transfer of INNS was also carried out to ensure compliance with the Invasive Alien Species (Enforcement and Permitting) (Amendment) Order 2019. This concluded that there is a low risk of transfer of INNS of Drought Plan actions and of the drought permit/orders for surface and groundwater options. There is some risk relating to monitoring and mitigation measures if surveyors or equipment enter surface waters, although this can be adequately manged through adherence to strict biosecurity protocols.

A Marine Conservation Zone (MCZ) assessment was carried out for the WRMP to consider an option at Peacehaven for water reuse. There are no options in the Drought Plan that could result in any impacts on features of an MCZ and no further consideration of this is required.

3.5 Screening assessment: demand side actions For DAPD4 (Drought Order and full phase 4 restrictions in place) the potential effects relate to population and human health, specifically:

 loss of earnings for small businesses and people working in water-related jobs (e.g. mechanical car-wash, commercial property cleaners, window cleaners, gardeners, leisure industry, tourism and recreation sectors);  lack of dust suppression resulting in air quality impacts;  industrial output for some businesses if equipment cannot be cleaned sufficiently; and  possible longer term costs related to ban on cleaning of commercial vehicles, boats, aircraft and railway rolling stock (e.g. repainting/replacement of bodywork required, additional fuel costs due to increased fouling of hulls).

Mitigation has been put in place to reduce the effect of these measures on population and human health. This includes:

 an Extreme Drought Action Plan which includes measures to delay the need for implementing full phase 4 restrictions such as pressure management, small desalination units and potable water tankering by sea (see Section 4 in the Drought Plan);  a robust drought communications plan;  developing media and communications plans to explain the need for restrictions; and  specific communications and exceptions put in place for vulnerable people (note that further research is being carried out to improve understanding of how we can support customers and assist with individual needs and the Drought Plan also includes building on the relationships maintained by our Vulnerability Strategy Team). Full phase 4 restrictions on demand would only be put in place in a severe drought scenario (such as a one in 500 year drought event with a probability of occurrence of 0.2 per cent in any given year). In WRMP24 the levels of resilience will be further enhanced, such that our long term water resources management plan offers 1 in 500 year levels of drought resilience (0.2% probability of occurrence in any given year) without recourse to Level 4 drought restrictions. This means that, in due course, the risk of level 4 restrictions will become more remote, as long term plans build in greater levels of resilience to extreme drought events.

Inclusion of mitigation will protect the most vulnerable members of the community. Given the probability of this action being taken and the temporary nature of the action it is not considered that there would be a significant effect on population and human health.

3.6 Screening assessment: supply side actions There are a number of options which have been considered in relation to supply side actions which require applications for drought permits/orders to be made. These options relate to DAPS2 (infrastructural connectivity and source improvements), DAPS3 (disused sources) and DAP6/7.

The locations of surface water and groundwater options (sites) are shown in Figure 3.1 and are listed below.

Surface water:

 River Ouse (Winter period: for use autumn - spring) (Abstractions at Ardingly Reservoir and Barcombe Mills - linked to Ardingly Reservoir)  River Ouse (Summer period: for use only in summer) (Abstractions at Ardingly Reservoir and Barcombe Mills - linked to Ardingly Reservoir)  River Cuckmere (Arlington Reservoir) Groundwater:

 Chasewood  Balcombe  Oaklands/Southlands 18

 Hackenden  Halling No.8 The order of application of drought permits/orders will be specific to the drought experienced. The surface water options are likely to be used before the groundwater options.

Consideration of the Drought Plan actions (relating to DAPS2,3,6 and 7) in relation to SEA topics is presented in Section 3.6.

Figure 3.1: Locations of drought permit/order sites

3.6.1 Surface water options The three surface water sites are considered most likely to be used at a moderate (one in 200 year) or severe drought (one in 500 year). The surface water options involve a reduction in the Minimum Residual Flow (MRF). This is the rate of flow (discharge) that must be left in a watercourse supporting abstraction, effectively it is a predefined rate of flow at which abstraction from a watercourse must cease.

For the River Ouse the drought permit/order option involves maintaining the MRF at 10 Ml/d and abstraction of everything above this up to the licensable limit, with the same MRF being used for the winter and summer options. The winter permit also includes an option to reduce augmentation from Ardingly Reservoir. As effects of this option would differ depending on the season, the assessment of the options has been separated into the winter period and summer period.

Assumptions

For the purposes of assessing the potential impacts of the drought permits/orders relating to surface water sources it has been assumed that:

 all appropriate infrastructure is in place; and  abstracted water meets all quality criteria associated with both Environment Agency consenting requirements and requirements for potable supply. The assessment assumes that construction work is not required and therefore the key pathways to an effect would be related to the abstraction of additional water from an existing riverine source. It is likely that the baseline conditions would already incorporate the effects of a drought, given that the options are not put in place until moderate drought status is reached. As detailed in Table 3.2 there are potential significant effects relating to surface water options for population and human health, biodiversity, flora and fauna and water. These effects are considered for each drought permit/order.

3.6.2 River Ouse (winter period) drought permit/order The River Ouse (winter) drought permit/order option involves maintaining the MRF at 10 Ml/d and abstraction of everything above this up to the licensable limit from autumn to spring. The River Ouse winter drought permit/order also includes an option to reduce the augmentation from 4Ml/d to 2 or 1Ml/d, in order to protect the reservoir. Information on the current operating licence and nature of the drought permit/order is provided in Section 3.3.8 and Appendix G of the Drought Plan (River Ouse Draft Drought Permit/Order). The assessment is informed by Appendix G and the relevant supporting documents outlined in Section 3.2.3 of the Drought Plan.

Population and human health

There are potential effects on the population from a reduction in water quality and flows in the upper reaches of the river and from impacts on the landscape and amenity value of the area. There may also be a requirement to restrict angling on certain reaches under specific conditions.

This could reduce the recreational value of the River Ouse with potential for economic impacts from loss of angling, boating and walking opportunities which could impact the local community

and tourism, although these effects are small in winter months. A reduction in river water quality (see details below) from decreased dilution of sewage effluent or algal blooms could impact livestock and domestic animals, and there may be an increased risk to human health from contact with the water during recreational activities.

To mitigate these effects the drought permit/order includes the following actions:

 weekly monitoring of water quality at key sites on the River Ouse;  liaison with angling clubs to communication the need for restrictions;  provision of information to the public and landowners to explain the reduction in water quality and potential risks;  information boards at key locations (e.g. Barcombe Mills) to explain the drought mitigation measures; and  emergency release of water if required to flush algal blooms. These effects would be temporary and particularly during the winter months would have a lower impact on tourism and on the economy. With incorporation of mitigation there would be no likely significant effects.

Biodiversity, flora and fauna

Designated sites

The designated nature conservation sites relevant to the River Ouse abstraction are shown in Figure A1 in Appendix A.

There are no European sites downstream of the drought permit/order locations that are in hydrological connectivity with the River Ouse and therefore no potential for significant effects on European designated sites.

There are 10 SSSIs downstream of the Drought Permit locations (Asham Quarry, Brighton to Newhaven Cliffs, Clayton to Offham Escarpment, Firle Escarpment, Lewes Brooks, Lewes Downs, Offham Marshes, Southerham Grey Pit, Southerham Machine Bottom Pit, Southerham Works Pit). Southerham Grey Pit SSSI is in hydrological connectivity however the features are not water-dependent.

Ardingly reservoir is designated as a Site of Nature Conservation Importance (SNCI) and a Local Nature Reserve (LNR) and the habitat supports diverse fish and wintering bird assemblages. The effects on habitats and species are outlined below. With the incorporation of a programme of monitoring and mitigation there are no likely significant effects on the SNCI or LNR.

Habitats and species

Specific habitat surveys have not been undertaken but the following generic habitats are present along the River Ouse:

 open water (instream) habitats including suitable fish spawning habitat  riparian (marginal) vegetation  ditches  grazing marsh 22

 woodland (including ancient and semi-natural woodland priority habitat) The species present include birds, fish (including salmonid fish, lamprey, bullhead, shad and European eel), otter, reptiles and amphibians.

The key effects on biodiversity are summarised below. Further details are provided in Table 6.1 of Drought Plan Appendix G.

A reduction in water velocity, depth and volume resulting in:

 smothering of vegetation and spawning gravel with fine sediments with potential for effects on vegetation and on macroinvertebrate habitats leading to a loss of cover for fish and potential implications for spawning;  reduction in fish pass efficacy/fish ability to negotiate other obstacles with consequences for migration and spawning and potential for entrapment in isolated features; and  exposure of aquatic habitats and marginal vegetation leading to habitat degradation. These effects could have longer term implications for biodiversity and may be significant, in particular the effects on migratory fish which rely on access to suitable spawning habitats. The key periods for sea trout migration (October to December) and spawning (January/February) occur when the drought permit/order would be in place and therefore reduced flows are likely to have an effect.

A reduction in river water quality resulting in:

 fish mortality or reduction in fish ‘fitness’ with potential effects on spawning success.  changes in dissolved oxygen and nutrient concentrations leading to increased algae growth and reduction in habitat quality. Mitigation

A hierarchy of monitoring and mitigation has been put in place to address the potentially significant effects. Monitoring of key sites across the main River Ouse channel is carried out before, during and after the implementation of a drought permit/order, including on a weekly basis during the period when the drought permit/order is implemented. Macro-invertebrate surveys and detailed inspections of known / potential sea trout redds would be carried out on a seasonal basis for 12 months following the end of the drought permit/order. Work will be carried out to determine the effective use and suitable locations of bubble curtains and continuous saline monitoring will provide data on the presence of a saline wedge upstream of Hamsey Weir.

If the drought permit/order is granted then initial mitigation would be put in place including modification of fish passes and flows over key structures, communication with landowners concerning in-channel modification options (e.g. channel narrowing), pollution prevention and potential for water quality issues (see Table 5.1 in Drought Plan Appendix G)..

There are also a number of reactive mitigation measures for which implementation is informed by the ongoing monitoring (see Table 5.2 in Drought Plan Appendix G). The key measures include:

 clearing debris from fish passes;  fish rescue, with the release of fish to a pre-agreed on-line River Ouse reach not subject to similar water quality impacts or pre-agreed off-line temporary oxygenated holding pond;  enhancement of riverine structures at other locations;  liaison with angling clubs to communication the need for restrictions;  information boards at key locations (e.g. Barcombe Mills) to explain the drought mitigation measures;  emergency release of water if required to flush algal blooms; and  undertake cleaning (e.g. raking or pressure washing in Autumn) of known sea trout redds that have deteriorated in quality since pre-drought condition assessment; There is also a plan for post-drought monitoring and restoration which will facilitate a timely reversal of the effects.

Residual effects

Taking into account the ability of the riverine ecosystem to recover from climatic events such as drought and the post-drought monitoring and restoration, the ecosystem is likely to recover in the months following the end of the drought period and return of abstraction to pre-drought permit levels. There is potential for effects on the free movement and spawning of migratory and non-migratory fish species and some uncertainty about the long term impacts on recruitment. However, the mitigation measures proposed are extensive and well-proven. The effects are likely to be short in duration and temporary in nature and it is therefore concluded that there would be no significant residual effects.

Water

The WFD water bodies relevant to the River Ouse abstraction are shown in Figure A1 in Appendix A of this report. The ‘Shell Brook upstream of Ardingly Reservoir’ water body feeds into ‘Ardingly Reservoir’ water body and its flow out is regulated by a compensation release. The Shell Brook water body is designated as heavily modified as a result of the impoundment release, and is currently at poor status overall. Modelling of the change in MRF in winter months has demonstrated that there are generally small effects on flows, levels and velocities at different points within the Ardingly System and no significant impacts on water quality. Changes to augmentation from Ardingly Reservoir from 4Ml/d to 2 or 1Ml/d could have a temporary effect on flows and therefore on macroinvertebrates and fish however there is sufficient mitigation in place to address these effects.

The Ardingly Reservoir water body is also classed as heavily modified. Operation under a permit would limit the compensation release to the minimum of 4Ml/d and whilst this could have a temporary effect on water quality and fish, the mitigation outlined above would address this temporary impact.

The water bodies downstream are also not predicted to be affected by the limited changes in flows and water quality as a result of the drought permit/order in winter. There is some uncertainty in relation to flows and the effect on fish passage as there are structures that could potentially hinder fish migration if flows and water levels are reduced. To address this concern, monitoring and mitigation has been incorporated into the options. If monitoring shows a marked reduction in flows then mitigation in the form of in-channel modification options (e.g. channel

narrowing using stone filled gabion baskets or sandbags) would be implemented to maintain a minimum flow. Based on the current information it is considered that the drought permit/order would not lead to deterioration in status of quality elements and there are no predicted significant effects on WFD water bodies.

Potential effects on water quality include changes in physico-chemical parameters as a result of a decrease in effluent dilution capacity, decrease in dissolved oxygen levels and changes in pH. Further details are provided in Table 3.1 of Drought Plan Appendix G. Monitoring of key sites across the main River Ouse would be carried out before, during and after the implementation of a drought permit/order. If required, the following mitigation would be implemented to address the potential effects:

 deployment of oxygenation kits;  in-channel modification options (e.g. channel narrowing) which would improve flows thereby increasing dissolved oxygen levels and avoiding algal blooms;  emergency release of water from Ardingly reservoir (if available) in response to a major pollution incident or movement of the saline wedge upstream of Hamsey Weir;  deployment of bubble curtains to maintain oxygen concentrations. It is considered that with the inclusion of mitigation that there would be no significant effects on water quality from the River Ouse (winter period) drought permit/order.

A summary of the SEA screening assessment is presented in Table 3.3.

Table 3.3: Identification of significant effects of the River Ouse (winter period) drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Population and human Yes Yes No health

Biodiversity, flora and Yes Yes No fauna

Water Yes Yes No

3.6.3 River Ouse (summer period) drought permit/order The River Ouse (summer) drought permit/order option involves maintaining the MRF at 10 Ml/d and abstraction of everything above this up to the licensable limit. Information on the current operating licence and nature of the drought permit/order is provided in Appendix J of the Drought Plan (River Ouse Draft Drought Permit/Order). The assessment is informed by Appendix I and the relevant supporting documents outlined in Section 3.2.3 of the Drought Plan.

Population and human health

As with the River Ouse (winter) drought permit/order there are potential effects on the population from a reduction in water quality and flows in the upper reaches of the river. The effects on landscape would be more pronounced in summer. If constraints are placed on water- related activities such as angling and boating these would be experienced by a greater number of people and could have greater economic impacts in summer compared to the same scenario in winter.

A reduction in river water quality (see details below) from decreased dilution of sewage effluent or algal blooms could impact livestock and domestic animals, and there may be an increased risk to human health from contact with the water during recreational activities.

To mitigate these effects the drought permit/order includes the following actions:

 weekly monitoring of water quality at key sites on the River Ouse;  liaison with angling clubs to communication the need for restrictions;  provision of information to the public and landowners to explain the reduction in water quality and potential risks;  information boards at key locations (e.g. Barcombe Mills) to explain the drought mitigation measures; and  emergency release of water if required to flush algal blooms. If the River Ouse (summer) drought permit/order is required, it is considered likely that there would be a reliance on mitigation to sufficiently reduce the level of impact. Given the temporary nature of the drought permit/order and the inclusion of mitigation it is not considered that there would be significant effects.

Biodiversity, flora and fauna

Designated sites

The designated nature conservation sites relevant to the River Ouse abstraction are shown in Figure A1 in Appendix A of this appendix.

Ardingly reservoir is designated as a Site of Nature Conservation Importance (SNCI) and a Local Nature reserve (LNR) and the habitat supports diverse fish assemblage. The effects on habitats and species are outlined below. With the incorporation of a programme of monitoring and mitigation there are no likely significant effects on the SNCI or LNR.

Habitats and species

Specific habitat surveys have not been undertaken but the following generic habitats are present along the River Ouse:

 open water (instream) habitats including suitable fish spawning habitat  riparian (marginal) vegetation  ditches  grazing marsh  woodland (including ancient and semi-natural woodland priority habitat) The species present include birds, fish (including salmonid fish, lamprey, shad, bullhead and European eel), otter, reptiles and amphibians.

The key effects on biodiversity are summarised below. Further details are provided in Drought Plan Appendix J.

A reduction in water velocity, depth and volume resulting in:

 smothering of vegetation and spawning gravel with fine sediments with potential for effects on vegetation and on macroinvertebrate habitats leading to a loss of cover for fish and potential implications for spawning;  reduction in fish pass efficacy/fish ability to negotiate other obstacles with consequences for migration and spawning and potential for entrapment in isolated features;  movement of saline wedge upstream in the Lower Ouse resulting in ecological community change, and  exposure of aquatic habitats and marginal vegetation leading to habitat degradation. These effects could have longer term implications for biodiversity and may be significant, in particular the effects on migratory fish which rely on access to suitable spawning habitats.

A reduction in river water quality resulting in:

 fish mortality or reduction in fish ‘fitness’ with potential effects on spawning success; and  changes in dissolved oxygen and nutrient concentrations leading to increased algae growth and reduction in habitat quality. Mitigation

A hierarchy of monitoring and mitigation has been put in place to address the potentially significant effects. Monitoring of key sites across the main River Ouse channel is carried out before, during and after the implementation of a drought permit/order, including on a weekly basis during the period when the drought permit/order is implemented. This includes macroinvertebrate surveys and detailed inspections of known / potential sea trout redds would be carried out on a seasonal basis for 12 months following the end of the drought permit/order. Work will be carried out to determine the effective use and suitable locations of bubble curtains and continuous saline monitoring will provide data on the presence of a saline wedge upstream of Hamsey Weir.

There are also a number of reactive mitigation measures for which implementation is informed by the ongoing monitoring (see Drought Plan Appendix I). The key measures include:

 clearing debris from fish passes;  fish rescue, with the release of fish to a pre-agreed on-line River Ouse reach not subject to similar water quality impacts or pre-agreed off-line temporary oxygenated holding pond;  enhancement of riverine structures at other locations;  liaison with angling clubs to communication the need for restrictions;  information boards at key locations (e.g. Barcombe Mills) to explain the drought mitigation measures; and  emergency release of water if required to flush algal blooms. There is also a plan for post-drought monitoring and restoration which will facilitate a timely reversal the of the effects.

Residual effects

The duration of ecosystem recovery is dependent on the implementation period of the drought permit/order. It is likely that recovery would take longer for a summer drought permit/order compared to a winter drought permit/order. Under a summer drought permit/order scenario there would be a reliance on mitigation to sufficiently reduce the level of impact. Ecosystem recovery would also therefore depend on the extent and success of mitigation measures employed.

The assessment has considered the suite of measures proposed. The monitoring programme, which incorporates set trigger points for the implementation of mitigation, is considered sufficiently robust to avoid significant effects. It is likely that there would still be detectable changes in macroinvertebrate communities for some months after a return to baseline conditions and there would need to be sustained river flows to remove accumulated sediments. It is also possible that there could be a reduction in fish population which may be evident in subsequent years, however it is important to note that effects on fish populations would already occur under the baseline scenario during a moderate to severe drought without intervention.

Water

The WFD water bodies relevant to the River Ouse abstraction are shown in Figure A1 in Appendix A of this report. The ‘Shell Brook upstream of Ardingly Reservoir’ water body feeds into the ‘Ardingly Reservoir’ water body and its flow out is regulated by a compensation release. This water body is designated as heavily modified as a result of the impoundment release and is currently at poor status overall. Modelling of the change in MRF in summer months has demonstrated that there are generally small effects on flows, levels and velocities at different points within the Ardingly System and no significant impacts on water quality.

The Ardingly Reservoir water body is also classed as heavily modified. Operation under a permit would limit the compensation release to the minimum of 4Ml/d and whilst this could have 28

a temporary effect on water quality and fish, the mitigation outlined above would address this temporary impact.

There is an additional abstraction downstream at Barcombe Mills in the ‘River Ouse between Isfield and the coast’ water body. In particular, the fish quality element which is already at poor status could be affected by a reduction in freshwater flows as a direct result of the permit, although modelling showed only a small drop in water levels over key weirs. There is also a risk of the saline wedge moving upstream in summer months. Mitigation has been incorporated including the provision of in-channel modification options (e.g. channel narrowing) and the potential to release water from Ardingly to flush the saline wedge. Based on the current information it is considered that the drought permit/order would not lead to deterioration in status of quality elements and there are no significant effects on WFD water bodies.

Potential effects on water quality include changes in physico-chemical parameters as a result of a decrease in effluent dilution capacity, decrease in dissolved oxygen levels and changes in pH. Further details are provided in Drought Plan Appendix J. Monitoring of key sites across the main River Ouse would be carried out before, during and after the implementation of a drought permit/order. If required the following temporary mitigation would be implemented to address the potential effects:

 deployment of oxygenation kits;  in-channel modification options (e.g. channel narrowing) which would improve flows thereby increasing dissolved oxygen levels and avoiding algal blooms;  emergency release of water from Ardingly reservoir (if available) in response to a major pollution incident or movement of the saline wedge upstream of Hamsey Weir; and  deployment of bubble curtains to maintain oxygen concentrations. It is considered that with the inclusion of mitigation that there would be no significant effects on water quality from the River Ouse (summer period) drought permit/order.

A summary of the screening assessment is presented in Table 3.4.

Table 3.4: Identification of significant effects of the River Ouse (summer period) drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Population and human Yes Yes No health

Biodiversity, flora and Yes Yes No fauna

Water Yes Yes No

3.6.4 River Cuckmere (winter period) drought permit/order The River Cuckmere drought permit/order involves reducing the MRF from 9.09Ml/d to 4.54Ml/d in winter combined with no augmentation from Arlington Reservoir. Information on the current operating licence and nature of the drought permit/order is provided in Appendix J of the Drought Plan (Cuckmere Draft Drought Permit/Order). The assessment is informed by Appendix I and the relevant supporting documents outlined in Section 3.2.3 of the Drought Plan.

Population and human health

There is potential for reduced flows and drying out of some channels in the upper reaches of the River Cuckmere and Arlington Reservoir, thereby reducing the aesthetic and recreational value to the local community and tourists. There may be a reduction in day tickets available to anglers and activities such as walking, boating and use of riverside pubs may be less popular. There may also be a reduction in water quality from decreased dilution of sewage effluent or algal blooms could impact human health and livestock or domestic animals.

To mitigate these effects the drought permit/order includes the following actions:

 weekly monitoring of water quality at key sites on the River Cuckmere and at Arlington Reservoir;  liaison with angling clubs to communication the need for restrictions;  provision of information to the public and landowners to explain the reduction in water quality and potential risks; and  information boards at key locations to explain the drought mitigation measures. These effects would be temporary and as the permit/order would be in place in during winter months there would be limited impacts on tourism and on the economy. With incorporation of mitigation there would be no likely significant effects.

Biodiversity, flora and fauna

The designated nature conservation sites relevant to the River Cuckmere abstraction are shown in Figure A2 in Appendix A of this report.

Designated sites

There are no European sites downstream of the drought permit/order location that are in hydrological connectivity with the Cuckmere abstraction. There are no significant effects on European sites.

There are five SSSIs downstream of the Drought Permit locations (Firle Escarpment, Lullington Heath, Milton Gate Marsh, Seaford to Beachy Head – West Dean Brooks, Wilmington Downs). Milton Gate Marsh SSSI and Seaford to Beachy Head – West Dean Brooks SSSI are in hydrological connectivity and further studies have been carried out to assess the potential for effects on features of the SSSIs.

For Milton Gate Marsh SSSI it was found that the reduced MRF would not affect flood flows and therefore the influence of the drought permit/order on the hydrological functioning of the SSSI was considered unlikely to be significant. For the West Dean Brooks SSSI, it was considered that these were impacted through groundwater flows and the operation of Milton 30

Lock and as a result would not be impacted by the operation of a drought permit/order. These studies have therefore concluded that there are no likely significant effects on SSSIs (see Appendix L of the Drought Plan).

Nine SNCIs have been identified within 2km of the River Cuckmere. A review of the location of these sites in relation to the river (i.e. the potential for hydrological links), and the habitats they support, resulted in the screening out of all but Michelham Priory SNCI. Michelham Priory does have a hydrological link to the river, but it is located several kilometres upstream of the abstraction point. Effects on water levels associated with the operation of the drought permit, at this distance upstream of the abstraction, are not likely to be significant.

Habitats and species

Specific habitat surveys have not been undertaken but the following generic habitats are present along the River Cuckmere:

 open water (instream) habitats including suitable fish spawning habitat  riparian (marginal) vegetation  ditches  lowland fens (priority habitat)  woodland (including ancient and semi-natural woodland priority habitat)  wet grassland (note that this occurs within the SSSI and there are no significant effects on this habitat). The species present include:

 fish (including salmonid fish, lamprey, bullhead, European eel and cyprinds)  macroinvertebrates  macrophytes  water vole and otter  riparian birds. The key effects on biodiversity are summarised below. Further details are provided in Drought Plan Appendix J.

A reduction in water velocity, depth and volume resulting in:

A reduction in river water quality resulting in:

Mitigation To address the potential for significant effects mitigation has been incorporated into the drought permit/order. These measures and the triggers for implementing the measures are detailed in Section 5.5 of Drought Plan Appendix H. The mitigation includes the following:  clearing debris from fish passes;  fish rescue with the release of fish to a pre-agreed on-line River Cuckmere reach not subject to similar water quality impacts or pre-agreed off-line temporary oxygenated holding pond;  enhancement of riverine structures at other locations;  liaison with angling clubs to communication the need for restrictions;  alert the Environment Agency to observed pollution events and liaise with respect to drought monitoring and mitigation requirements;  information boards at key locations to explain the drought mitigation measures; and  undertake cleaning (e.g. raking or pressure washing in Autumn) of known sea trout redds that have deteriorated in quality since pre-drought condition assessment. It is considered that with the inclusion of mitigation that there would be no significant effects on biodiversity from the River Cuckmere drought permit/order.

Water

The WFD water bodies relevant to the River Cuckmere abstraction are shown in Figure A2 in Appendix A of this report. The abstraction is from the ‘Cuckmere from Alfriston to Arlington’ water body which is a heavily modified water body that was classified as moderate overall in 2019. Water is transferred to the ‘Arlington Reservoir’ water body which is classed as an artificial lake. The two waterbodies downstream of the abstraction are Cuckmere transitional water body (moderate status) and Sussex coastal water body (moderate status).

The drought permit/order allows for additional water to be abstracted from the ‘Cuckmere from Alfriston to Arlington’ water body and either used for supply or put directly into Arlington Reservoir. This would relieve pressure on the reservoir by slowing drawdown or providing additional water and would not therefore affect the status of the reservoir water body.

The reduction in the MRF is also not predicted to significantly affect any quality element within the Cuckmere from Alfriston to Arlington water body, from which the abstraction occurs. Studies have demonstrated no significant effects on macroinvertebrate communities in relation to changes in flow. It is possible that fish may experience some adverse effects, depending on the duration of the permit. The timing of the winter only abstraction avoids the key periods of fish migration and spawning for most species with the exception of sea trout. The monitoring programme will continue and the results will be analysed in respect of WFD objectives. Based on the current information the drought permit/order would not lead to deterioration in status of quality elements and there are no significant effects on WFD water bodies.

 deployment of oxygenation kits if required; and  SEW to monitor river and reservoir water quality. It is considered that with the inclusion of mitigation that there would be no significant effects on water quality from the River Cuckmere drought permit/order.

A summary of the SEA screening assessment is presented in Table 3.5.

Table 3.5: Identification of significant effects of the River Cuckmere drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Population and human Yes Yes No health

Biodiversity, flora and Yes Yes No fauna

Water Yes Yes No

3.6.5 Groundwater options There are five groundwater sites where drought permit/order applications could be made. This is only likely to occur in a worse than one in 200 year (0.5 per cent probability of occurring in any given year) drought event (termed a ‘severe’ drought in our scenarios presented in section 8.2 of the Drought Plan). As a result, the applications are more likely to be for drought orders, as the resource situation is likely to be reaching critical levels by that point.

Three groundwater sites (Chasewood, Hackenden, and Balcombe) are currently disused groundwater sources which have been used as supply sources in the past. The reasons for their disuse are typically due to poor yield and/or inadequate facilities to treat poor water quality. We no longer hold abstraction licences for any of these sources and so if they were to be brought back online, a drought permit/order would need to be granted. None of the applications would be to exceed previous licensed conditions and there are no restoring sustainable abstraction issues in any of the catchments.

Southlands and Oaklands drought permit/order involves an increase of existing abstraction licences from the Hythe Beds formation. Two new boreholes were licensed within the last three years, but not to the full output quantities originally applied for as it was deemed unnecessary by the Environment Agency to support the average and peak supply in RZ5. Pumping tests of the confined boreholes have proved that there is no impact on surface water features. 33

In 2005, we drilled and tested the Halling No.8 borehole and proved a connection between adjacent quarry water and the chalk borehole water. The drought permit/order would be required to increase the existing Chalk licence to be able to take advantage of the connection and abstract the quarry water.

For the purposes of assessing the potential impacts of the drought permits/orders relating to groundwater sources it has been assumed that:

 all appropriate infrastructure is in place at the source;  pump testing will have been undertaken and used to confirm the extent of any surface water drawdown and inform the need to re-scope this assessment with respect to potential groundwater effects;  abstracted water meets all quality criteria associated with both Environment Agency consenting requirements and requirements for potable supply; and  all abstracted water is transferred to supply via existing pipe works or temporary pipes. Assessment

The assessment assumes that construction work is not required and therefore the key pathways to an effect would be related to the abstraction of additional water from an existing source. As detailed in Table 3.2 there are potential significant effects relating to groundwater options for biodiversity, flora and fauna, water and cultural heritage.

Searches of the Kent and Hampshire County Council’s heritage databases i.e. the Heritage Environment Records (HER) were carried out and heritage designed sites mapped (see Section 6 of the Drought Plan and Appendix S). Designated heritage sites would not be affected by the groundwater drought permit/orders. We consider that the only pathway by which there could be a potential impact on the historic environment is from increased borehole abstraction, lowering the water table and leading to an adverse local impact on archaeological assets or deposits. This situation could potentially arise at either Halling No.8 or Oaklands and Southlands drought permit/order locations and is considered under these options.

These potential effects relating to each groundwater drought permit/order are described below.

3.6.6 Chasewood drought permit/order The Chasewood drought permit/order option involves reinstating the Chasewood source to provide additional water resources in times of drought in line with the historic abstraction licence (i.e. delivery of 1.5Ml/d into SEW Resource Zone 1). Information on the nature of the drought permit/order is provided in Appendix J of the Drought Plan (Chasewood Draft Drought Permit/Order). The assessment is informed by Drought Plan Appendix I and the relevant supporting documents outlined in Section 3.2.3 of the Drought Plan.

Biodiversity, flora and fauna

The designated nature conservation sites relevant to the Chasewood drought permit/order are shown in Figure A3 in Appendix A of this report.

There are no European sites within 5km. There is one SSSI (Eridge Park SSSI) and three SNCIs (Frant Meadows SNCI, Hawkenbury Farm Meadows SNCI and Clays Wood SNCI)

within 2km but there is no hydrological connectivity between the source and these sites and therefore no significant effects.

Deciduous woodland (a priority habitat) is present on site and in scattered locations within 250m of the site. This habitat would not be affected by the drought permit/order. The aquifer is confined at this location and there are no links to bodies of surface water and therefore no effects on habitats or species.

Water

The WFD water bodies relevant to the Chasewood drought permit/order are shown in Figure A3 in Appendix A. The Site falls within the Kent Weald Western-Medway WFD groundwater body. This water body was classified as Poor overall, but had Good quantitative status in 2019.

The effect of a small temporary additional abstraction from this source is considered to have a negligible effect on groundwater body quantitative status and would not affect chemical status. We are currently undertaking further investigative work to better understand sustainability of abstractions. Findings from investigations will be used to update this assessment in the future. Based on the current information there are no likely significant effects relating to effects on WFD water bodies.

There is one Source Protection Zone (SPZ) within 500m of the site, approximately 180m south. This would not be affected by the drought permit/order. There are two NVZs within 2km of the Site. These would not be affected by the drought permit/order. There are no potential adverse effects associated with flooding.

The Chasewood abstraction is situated over an aquifer of high vulnerability, meaning that pollution is easily transmitted to groundwater due to the presence of high-leaching soils and the absence of low permeability superficial deposits. The risk can be manged with the implementation of standard good practice mitigation measures.

A summary of the SEA screening assessment is presented in Table 3.6.

Table 3.6: Identification of significant effects of the Chasewood drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Biodiversity, flora and No No No fauna

Water No No No

3.6.7 Southlands and Oaklands drought permit/order The Southlands and Oaklands drought permit/order option involves increasing the use of two boreholes from the confined Lower Greensand to the borehole yield capacity. These two boreholes in separate locations, were recently licenced and both abstract water from the highly 35

confined Hythe Beds formation, around 137 – 139m below ground level. Abstraction licences have been granted for these sources but not to the full output quantities applied for as it was deemed unnecessary by the Environment Agency to support the average and peak supply in Resource Zone 5. Information on the nature of the drought permit/order is provided in Appendix J of the Drought Plan (Southlands and Oaklands Draft Drought Permit/Order). The assessment is informed by Appendix I and the relevant supporting documents outlined in Section 3.2.3 in the Drought Plan.

Biodiversity, flora and fauna

The designated nature conservation sites relevant to the Southlands and Oaklands drought permit/order are shown in Figure A4 in Appendix A of this report.

There are four European sites within 5km (Woolmer Forest SAC, Shortheath Common SAC, East Hampshire Hangers SAC and The Wealden Heath Phase II SPA) but there is no hydrological connectivity between the source and these sites as the aquifer is confined.

There is an SSSI (Eridge Park SSSI) and three SNCIs (Frant Meadows SNCI, Hawkenbury Farm Meadows SNCI and Clays Wood SNCI) within 2km but there is no hydrological connectivity between the sources and these sites as the aquifer is confined.

Deciduous woodland (a priority habitat) is present within 250m of both Southlands and Oaklands sites. Good quality semi-improved grassland is also present within 250m of Oaklands. The aquifer is confined at this location and boreholes are unable to impact any surface water features and therefore there would be no effects on habitats or species from the drought permits/orders.

Water

The WFD water bodies relevant to the Southlands and Oaklands drought permit/order are shown in Figure A4 in Appendix A of this report. The site falls within the Godalming Lower Greensand WFD groundwater body. This water body was classified as Poor overall, but had Good quantitative status in 2019.

There is a SPZ 600m north west of the Southlands site and a SPZ 1.4km south of the Oaklands site but these would not be affected by the drought permit/order.

There are no NVZs within 2km of the Southlands site. The North Wey (Alton to Tilford) Nitrate Vulnerable Zone (NVZ) is 1km north of the Oaklands site. This would not be affected by the drought permit/order.

The Southlands site is situated over a principal bedrock aquifer of high vulnerability, meaning that pollution is easily transmitted to groundwater due to the presence of high-leaching soils and the absence of low permeability superficial deposits. The risk can be manged with the

implementation of standard good practice mitigation measures. The Oaklands site is situated over an unproductive aquifer.

There is a high risk of flooding from groundwater at Southlands up to 50m from the source, but this is not likely to affect any receptors. There are no potential adverse effects associated with flooding at Oaklands.

Cultural heritage

The data show the presence of archaeological remains and assets, including some in close proximity to the drought permit/order locations (see Figures in Appendix S of the Drought Plan (South East Water, 2021)). Further archaeological assessment and monitoring may be required. This would need to be agreed with the relevant Local Authority Archaeological Advisor. With incorporation of this mitigation the risk to HER is low and can be adequately addressed though the drought permit/order application process.

A summary of the SEA screening assessment is presented in Table 3.7.

Table 3.7: Identification of significant effects of the Southlands and Oaklands drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Biodiversity, flora and No No No fauna

Water No No No

Cultural heritage Yes Yes No

3.6.8 Balcombe drought permit/order The Balcombe Drought Permit option involves reinstating the source which was abandoned in 1981 due to poor yields to provide additional water resources in times of drought. Information on the nature of the drought permit/order is provided in Appendix J of the Drought Plan (Balcombe Draft Drought Permit/Order). The assessment is informed by Appendix I and the relevant supporting documents outlined in Section 3.2.3 of the Drought Plan.

Biodiversity, flora and fauna

The designated nature conservation sites relevant to the Balcombe drought permit/order are shown in Figure A5 in Appendix A of this report. There are no European sites within 5km. There are two SSSIs (Worth Forest SSSI and Cow Wood & Harry’s Wood SSSI) and four Local Wildlife Sites within 2km but there is no hydrological connectivity between the source and these sites.

Deciduous woodland and traditional orchards (priority habitats) occur within 250m of the site and a small area of good quality semi-improved grassland (a priority habitat) is located approximately 1.5km south west of the site.

The assessment takes into account the assumptions in Section 3.6.5 (i.e. transfer directly into the supply network, no drawdown effects on surface water features, appropriate water quality to meet Environment Agency consent and potable water quality requirements). On this basis there are no potential effects arising from the implementation of the Balcombe drought permit/order on environmental receptors due to the absence of a physical pathway between the source (of the water) and environmental receptors.

Water

The WFD water bodies relevant to the Balcombe drought permit/order are shown in Figure A5 in Appendix A of this report. The site falls within the Copthorne Tunbridge Wells Sands WFD groundwater body (good quantitative and good chemical status) and has connectivity with Stanford Brook riverine water body (overall moderate status). Water from the source would be transferred to Ardingly Reservoir via the ‘Shell Brook upstream of Ardingly Reservoir’ water body (overall poor status).

Although the exact extent of the cone of drawdown is unknown it is considered that for this abstraction drawdown will be in the region of 2km or less. Stanford Brook is approximately 1.8km from the Balcombe source, with less than a quarter of the water body length lying within 2km. Considering the distance and extent of possible drawdown there are no likely significant effects on the Stanford Brook WFD water body. Pump testing will be undertaken prior to a permit application and used to confirm the extent of any surface water drawdown and inform the need to re-scope this assessment with respect to potential groundwater effects.

Abstracted groundwater could be transferred via temporary pipework to the Shell Brook to augment Ardingly reservoir. There is a potential risk of transfer of INNS e.g. iron bacteria and biofilms from groundwater to surface water. Mitigation is required including:

 the incorporation of further testing of water to confirm no risk of bacterial transfer prior to implementation of this option; and  disinfection of temporary pipework and implementation of good practice biosecurity measures. With the inclusion of mitigation measures there are no likely significant effects on the Shell Brook upstream of Ardingly Reservoir WFD water body.

There are no SPZs or NVZs within 2km of the Balcombe source. The site itself is situated over an aquifer of high vulnerability, meaning that pollution is easily transmitted to groundwater due to the presence of high-leaching soils and the absence of low permeability superficial deposits.

The risk can be manged with the implementation of standard good practice mitigation measures. There are no potential adverse effects associated with flooding.

A summary of the SEA screening assessment is presented in Table 3.8.

Table 3.8: Identification of significant effects of the Balcombe drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Biodiversity, flora and No No No fauna

Water No No No

3.6.9 Hackenden drought permit/order The Hackenden Drought Permit option involves reinstating the source by recommissioning well No.1 (well No.2 has been sealed due to contamination). This is dependent on final testing of the quality and quantity of the source to confirm that the sealing of well No.2 has worked. The abstraction would be within the limits of the historic abstraction licence. Information on the nature of the drought permit/order is provided in Appendix J of the Drought Plan (Hackenden Draft Drought Permit/Order). The assessment is informed by Appendix I and the relevant supporting documents outlined in Section 3.2.3.

Biodiversity, flora and fauna

The designated nature conservation sites relevant to the Hackenden drought permit/order are shown in Figure A6 in Appendix A. There are no European sites or SSSIs within 5km. There are two SNCIs within 2km (Ashplatts Wood SNCI and Worth Way SNCI) but there is no hydrological connectivity between the source and these sites (see Section 6.3.5 in the DP).

Deciduous woodland (a priority habitat) occurs within 250m of the site and small areas of traditional orchard and good quality semi-improved grassland (also priority habitats) lie within 2km of the site. The aquifer is confined at this location and the abstraction would not impact any surface water features and therefore there would be no effects on habitats or species from this drought permits/order.

Water

The WFD water bodies relevant to the Hackenden drought permit/order are shown in Figure A6 in Appendix A. The Site falls within the Kent Weald Western-Medway WFD groundwater body. This water body was classified as Poor overall, but had Good quantitative status in 2019.

There are no SPZs within 2km of the Hackenden source. There are two nitrate vulnerable zones within 2km of the site:

 Eden Brook East of Lingfield NVZ (surface water) (covers the site)  Medway at Weir Wood NVZ (surface water) (1km south-west of the site). These would not be affected by the Hackenden drought permit/order.

The site itself is situated over an aquifer of high vulnerability, meaning that pollution is easily transmitted to groundwater due to the presence of high-leaching soils and the absence of low permeability superficial deposits. The risk can be manged with the implementation of standard good practice mitigation measures. There are no potential adverse effects associated with flooding.

A summary of the SEA screening assessment is presented in Table 3.9.

Table 3.9: Identification of significant effects of the Hackenden drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Biodiversity, flora and No No No fauna

Water No No No

3.6.10 Halling No.8 drought permit/order The Halling source currently comprises two operational boreholes (No.4 and No.7) and adits (a horizontal passage leading into a mine for the purposes of access or drainage) abstracting from the Upper Chalk horizons, and one borehole from the lower Greensand Formation (No.6). The source has current licences, which allow 2.2 Ml/d average from the Chalk and 3.0 Ml/d from the Greensand, with 4.0 Ml/d peak for both the aquifers.

Immediately adjacent the site to the north is a very large flooded quarry (the Grey Pit) which is now no longer worked. In 2005, South East Water drilled and tested the No 8 borehole on the edge of the site and proved that there was a connection between the lake water and the chalk water at this location (i.e. the abstraction from borehole No.8 is effectively from the quarry lake).

Currently the Grey Pit overflows during most of the year as the historic abstraction by the pit operator (Cemex) is no longer used. It now overflows from the eastern corner into the part of the adjacent Medway marshes, but this overflow stops during the summer months.

The source is adjacent to the lower part of the Medway catchment and is in hydrological continuity with the adjacent flooded quarry pit. The Medway at this location is tidal and a range of estuarine features are evidence (e.g. salt marsh, mudflats, creeks and tidal channels). Part of the marshland at this location is freshwater marsh, including the area into which the Grey Pit overflows during the winter months.

Information on the nature of the drought permit/order is provided in Appendix J of the Drought Plan (Halling No.8 Draft Drought Permit/Order). The assessment is informed by Appendix I and the relevant supporting documents outlined in Section 3.2.3 of the Drought Plan.

Biodiversity, flora and fauna

The designated nature conservation sites relevant to the Halling No.8 drought permit/order are shown in Figure A7 in Appendix A of this report. There are two European sites within 5km (North Downs Woodland SAC and Peter’s Pit SAC). North Downs Woodland SAC is not hydrologically connected with the source.

Primary groundwater flow has been shown to move eastwards towards the River Medway rather than South towards Peter’s Pit. There would be no change in the overall abstraction regime from the Grey Pit/Halling No.8 area, only a relocation of the locus of abstraction. Abstraction from Halling No.8 borehole would not significantly alter groundwater flow patterns in the vicinity of the abstraction and there would be no impact on any groundwater dependent features.

There is a hydrological pathway from the Halling No.8 source to the River Medway via Grey Pit and consideration has also been given to potential impacts on European sites downstream of this location. The changes in freshwater input as a result of the drought permit/order are extremely small in relation to the quantity of the dominant freshwater inputs. Given the tidally- dominated nature of the River Medway, and the extent of the change, there are no predicted effects on European sites in the River Medway. It is therefore concluded that there would be no significant effects on European sites.

There are three SSSIs (Halling to Trottiscliffe Escarpment SSSI, Holborough to Burham Marshes SSSI and Houlder and Monarch Hill Pits SSSI) within 2km. There may be a hydrological relationship between the SSSIs and the Halling No.8 source, but considering the habitats present, the small quantity of water being abstracted and the locations of the SSSIs, it is highly unlikely there would be any drawdown effects which could significantly affect designated features.

There are four Local Wildlife Sites (LWS) (River Medway and Marshes (TM03), Arable Field, Lad’s Farm (TM35), Leybourne Lakes (TM30) and South Hill and Houlder Quarries (ME10)) within 2km but there is no hydrological connectivity between the source and these sites and therefore no pathway to an effect.

There are a number of priority habitats within 2km of the site including ancient woodland, Ghyll woodland, coastal and floodplain grazing marsh, reedbeds and open water and numerous

species associated with these habitats including fish, macroinvertebrates, macrophytes, water vole, otter, bats and birds.

The effects of the drought permit/order relate to the drawdown of water from the flooded quarry pit. The reduced water depth and exposure of the littoral zone could lead to effects on habitats and species including:

 loss or modification of fish spawning and macroinvertebrate habitats;  loss or modification of potential crayfish and water vole habitats;  die-back of marginal vegetation;  loss of cover for prey species (e.g. tree roots, aquatic macrophyte stands);  reduction in lake water quality due to reduced dilution capacity with implications for fish, invertebrates and macrophytes;  increased growth of algae smothering vegetation and sediment and leading to impacts on water quality and potential impacts on fish spawning and fish fitness;  die-back of vegetation leading to oxygen depletion and potential for fish and invertebrate mortality; and  reduction in prey species for fish and otter. To address the potential for significant effects, a programme of monitoring and mitigation has been incorporated into the drought permit/order. In addition, further baseline data collection would be carried out to enable a better understanding of the existing environment. This would include an extended Phase 1 habitat survey (which would improve the understanding of the reliance of the adjacent Medway marshes habitat on the overflow from the lake); macroinvertebrate surveys; studies to identify fish habitat and communities; and water vole and crayfish surveys.

A monitoring programme would also be put in place prior to an application for a drought permit/order at Halling No.8 to collect data on key aspects, including water quality, macroinvertebrate assemblages, key habitats, algal and macrophyte growth.

With the current level of baseline data it is not possible to accurately assess the effects on habitats and species. However there is a clear commitment to further baseline data collection and also a stated intention to set up a monitoring programme. It is recommended that discussions with regulators are held at an early stage should there be a need to plan for a drought permit/order at Halling No.8. Regulators should also be consulted on the appropriate type and level of mitigation required to address effects during operation and in post-drought conditions. With a suitable monitoring and mitigation programme in place it is likely that significant effects can be avoided.

Water

The WFD water bodies relevant to the Halling No.8 drought permit/order are shown in Figure A7 in Appendix A of this report. The Site falls within the North Kent Medway Chalk WFD groundwater body (poor quantitative and poor chemical status) and is linked via Grey Pit to the Medway transitional water body (moderate status).

There would be no change in the overall abstraction regime from the Grey Pit/Halling No.8 area, only a relocation of the locus of abstraction. Abstraction from Halling No.8 borehole would not significantly alter groundwater flow patterns in the vicinity of the abstraction and there would

be no impact on any groundwater dependent features. There is no predicted effects on the quantitative or chemical status of the North Kent Medway Chalk WFD groundwater body.

The Halling No.8 source and the Medway transitional water body are hydrologically linked via Grey Pit. The changes in freshwater input as a result of the drought permit/order are extremely small in relation to the quantity of the dominant freshwater inputs. Given the tidally-dominated nature of the receiving water body and the extent of the change, there are no predicted effects on the Medway water body.

Cultural heritage

The data show the presence of archaeological remains and assets, including seven archaeological features which may be at risk within 1km of the source (see Appendix S in the Drought Plan (South East Water, 2021)). Further archaeological assessment and monitoring may be required. This would need to be agreed with the relevant Local Authority Archaeological Advisor. With incorporation of this mitigation, the risk to the Historic Environmental Record (HER) is low and can be adequately addressed though the Drought Permit application process.

A summary of the SEA screening assessment is presented in Table 3.10.

Table 3.10: Identification of significant effects of the Halling No.8 drought permit/order

Potential for SEA topic significant effects Mitigation required Residual effect without mitigation

Biodiversity, flora and Yes Yes No (uncertain) fauna

Water No No No

Cultural heritage Yes Yes No

3.7 Screening assessment summary With the incorporation of mitigation and the commitment to gathering further baseline data to inform monitoring and mitigation programmes, it is not considered likely that there would be any significant effects from the implementation of demand-side or supply-side actions.

3.8 Cumulative effects Consideration of cumulative effects has covered both intra-plan effects (effects that arise when a single receptor is affected by more than one effect from the Drought Plan actions) and inter- plan effects (effects that may arise when a receptor is affected by other plans or projects).

To understand the potential for intra-plan effects the Drought Plan actions are mapped against SEA topics where potentially significant effects have been identified (see Table 3.11).

Table 3.11: Cumulative effects of Drought Plan Actions

SEA topics with potential significant effects (without mitigation)

Drought Plan Actions Population and Biodiversity, Water Cultural human health flora and fauna heritage

DAPD4 Restrictions on Yes No No No uses of water through a Drought Order

River Ouse (winter Yes Yes Yes No period)

River Ouse (summer Yes Yes Yes No period)

River Cuckmere Yes Yes Yes No (Arlington Reservoir)

(DAPS2/3/6/7)

Chasewood No No No No

Balcombe No No No No

Oaklands/Southlands No No No Yes

Hackenden No No No No

Halling No.8 No Yes No Yes

Drought permit/order options

The key areas where potential cumulative effects could occur are:

 Population and human health - people living in proximity to the River Ouse could be affected by both restrictions on water use affecting households and businesses and by the surface water drought permit/order if there are impacts on water quality and restrictions on recreational activities. This could have an effect on both human health and on the local economy and could potentially be significant in summer months.  Water - there is a potential cumulative effect in the River Ouse if two drought permit/orders are used consecutively (i.e. in summer and winter) within the same catchment. This would only occur in a severe drought scenario (worse than 1 in 500 year drought) and is therefore is a very unlikely situation. If it did happen there would be an additive effect of abstracting additional water for a continuous period of over a 44

year. As this would remove the opportunity for the ecosystem to recover it could result in significant effects on water quality and on quality elements in WFD water bodies. A longer impact duration would result in a longer process of recovery with the potential for long term suppression of biological quality.  Biodiversity, flora and fauna - the fish and eel communities that would be affected by drought permit/orders are in separate catchments, however there could be a cumulative effect on migratory species if individuals are affected in river catchments which could have wider implications for populations. There would also be an additive effect on biodiversity if both summer and winter drought permits/orders are used consecutively in the River Ouse. This may result in a longer term suppression of environmental quality and subsequently longer recovery periods.  Cultural heritage - given the geographic separation and nature of the effects on the historic environment at Oaklands/Southlands and Halling No.8 there are no potential cumulative effects. The monitoring and mitigation measures proposed have been reviewed in relation to the potential cumulative effects. It is considered that all possible mitigation has been put in place and that trigger levels for implementing mitigation are appropriate. With incorporation of monitoring and mitigation it is considered that cumulative effects can be avoided.

The potential for cumulative effects with the options in the WRMP has been assessed in the SEA for the WRMP. The assessment considered in particular, the combined effects of the River Ouse drought permit/orders with the Arlington Reservoir (RES-24) and water reuse at Peacehaven (EFF-35) WRMP options. It was concluded that cumulative effects could be avoided through careful operational management (South East Water, 2019).

Consideration has also been given to the Drought Plan actions in combination with the activities of other neighbouring water companies. Most drought permits/orders are in separate resource zones (see Figure 3.1) so would avoid cumulative effects on the same resources/receptors.

The exception to this is Resource Zone 2 which contains the River Ouse, Hackenden and Balcombe drought permit/order options. The Hackenden source is within a confined aquifer and as a result it has been screened out. The Balcombe permit would impact the reach of the river upstream of Ardingly reservoir so is not considered to have an in combination effect alongside the River Ouse drought permit/order applications.

Considering both intra-plan and inter-plan effects, there are no likely significant cumulative effects of the Drought Plan actions.

4. Conclusions

This SEA determination and screening statement has considered the characteristics of the Drought Plan in relation to the key criteria listed in Annex II of the SEA Directive. A summary of the assessment is presented in Table 4.1.

Table 4.1: SEA screening criteria

SEA criteria Summary and relevant sections in this report

Plan characteristics

The degree to which the plan or The plan does not set a framework for other projects requiring programme sets a framework for development consent and EIA. Infrastructure projects supporting projects and other activities, either supply demand and resilience are addressed in the WRMP with regard to the location, nature, within 1:200 year dry weather/drought events and this is to be size and operating conditions or developed to include 1:500 year events for WRMP24. The by allocating resources. drought is considered to be an operational plan that identifies a sequence of specific tactical actions to be put in place as defined triggers are reached for more extreme events outside the 1:200 year WRMP planning scenario and these could potentially include drought orders or permits for which individual environmental assessments have been prepared and would be provided to support applications.

The degree to which the plan or The plan is not part of a hierarchy of plans. It is closely linked to programme influences other plans the WRMP but addresses the operational actions for events and programmes including those outside the WRMP 1:200 year planning scenario. in a hierarchy.

The relevance of the plan or Environmental considerations are built into the Drought Plan programme for the integration of measures identifying the sequence of protective actions to environmental considerations in mitigation and monitoring identified through the action specific particular with a view to promoting environmental assessment undertaken. There are no options for sustainable development. consideration for investment within the Drought Plan. Options to improve supply and resilience are assessed through the WRMP process which is subject to SEA.

Environmental problems relevant The Drought Plan addresses weather and climatic events that to the plan or programme. are likely to both effect the environment adversely and also create challenges for meeting water demand. The Drought Plan actions including sequencing of actions and the mitigation and

SEA criteria Summary and relevant sections in this report

monitoring measures are considered unlikely to result in significant environmental effects.

The relevance of the plan or The Drought Plan is considered not to effect implementation of programme for the implementation other EC legislation such as WFD or habitats directive or EIA of [European] Community directive. legislation on the environment (for example, plans and programmes linked to waste management or water protection).

Effects and area characteristics

The probability, duration, The overall probability of implementation of drought plan actions frequency and reversibility of the is very low (less than 1 in 200 year events as actions are only effects required in a moderate or worse drought scenario). With the incorporation of monitoring and mitigation the effects would be temporary and reversible and are likely to be short term (Sections 3.6 and 3.7).

The cumulative nature of the There are potential cumulative effects but mitigation measures effects are sufficient to address these (Section 3.8).

The transboundary nature of the There are no transboundary effects (Section 3.8) effects

The risks to human health or the There are some limited risks to human health which would be environment (for example, due to managed through a robust monitoring and mitigation programme accidents) (Sections 3.5 and 3.6).

The magnitude and spatial extent The Drought Plan actions including sequencing of actions and of the effects (geographical area the mitigation and monitoring measures are considered unlikely and size of the population likely to to result in significant environmental effects. be affected)

The value and vulnerability of the There are potential effects on cultural heritage but mitigation area likely to be affected due to measures are sufficient to address these (Sections 3.5 and 3.6). special natural characteristics or cultural heritage

Exceeded environmental quality There is a small risk of temporary breaches of environmental standards or limit values of quality standards but these would be rare short term events and intensive land-use

SEA criteria Summary and relevant sections in this report

mitigation measures are sufficient to address this risk (Sections 3.5 and 3.6).

The effects on areas or Effects on landscape would be temporary, small scale and are landscapes which have a not likely to be significant. recognised national, Community or international protection status.

The Drought Plan is considered an operational plan identifying sequences of actions responding to specified triggers for events outside the planning scenarios addressed by WRMP19.

With the incorporation of mitigation and the commitment to gathering further baseline data to inform monitoring and mitigation programmes, it is not considered likely that there would be any significant effects from the implementation of Drought Plan actions, including the drought permit/orders.

To specifically address the potential effects on the environment of the drought permits/orders assessments were carried out for each location in relation to the requirements of environmental legislation, including the following:

 a Habitat Regulations Assessment (HRA) (Appendix M of the Drought Plan);  an assessment of effects on SSSIs (Appendix L of the Drought Plan);  a Water Framework Directive Assessment (Appendix N of the drought plan) and an assessment of the risk of transfer of INNS (Appendix K); and  studies on river structures, condition of sea trout habitat and on eel passes (Appendix K). These studies together with the assessments made in the draft drought permit/order applications have facilitated the development of robust monitoring and mitigation programmes, which include measures pre, during and post-drought which would aid the protection of ecosystems and enable a quick recovery.

The SEA screening assessment considered both intra-plan and inter-plan cumulative effects. Potential cumulative effects were identified in relation to three SEA topics: population and human health, biodiversity and water. It is considered that the proposed mitigation measures are sufficient to address the potential effects. In addition, the probability of these effects occurring is very low. There are no likely significant cumulative effects relating to the actions in the Drought Plan.

In conclusion, the draft 2021 Drought Plan does not provide a framework for development consent unlike WRMP19 which includes all infrastructure development and resource development options likely to require planning consent and required to support dry weather/ drought resilience. The plan is an operational plan setting out how to respond to trigger events. There are no options for comparison but a sequence of actions against escalating conditions. For more extreme situations drought orders and permits could be required but detailed studies

and investigations have been undertaken and environmental assessments to support applications prepared. These have been used to assess the potential for likely significant effects taking account of their likelihood, duration and reversibility along with the additional mitigation and monitoring included and significant environmental effects are identified as unlikely. Therefore, this draft determination and screening statement concludes that the SEW 2021 draft Drought Plan is not required to be subject to SEA.

As part of the determination process views on this screening assessment will be sought from the statutory consultees.

References

Environment Agency (2021). Catchment Data Explorer. Available from: https://environment.data.gov.uk/catchment-planning [accessed 19 February 2021].

MAGIC (Multi-Agency Geographic Information for the Countryside) (2021). Interactive map. Available from: https://magic.defra.gov.uk/ [Accessed 19 February 2021]. South East Water (2019). Water Resource Management Plan 2020 to 2080. Available from: https://corporate.southeastwater.co.uk/about-us/our-plans/water-resources-management- plan-2019/ [Accessed 19 February 2021].

South East Water (2021). Our plan for dry weather and water shortages. South East Water’s drought plan (draft). March 2021.

Appendix A: Figures

Figure A1: River Ouse drought permit/order environmental constraints 52

Figure A2: River Cuckmere drought permit/order environmental constraints 53

Figure A3: Chasewood drought permit/order environmental constraints 54

Figure A4: Southlands and Oaklands drought permit/order environmental constraints 55

Figure A5: Balcombe drought permit/order environmental constraints 56

Figure A6: Hackenden drought permit/order environmental constraints 57

Figure A7: Halling No.8 drought permit/order environmental constraints

South East Water Rocfort Road Snodland Kent ME6 5AH southeastwater.co.uk