ta 11.3 regional water grid technical annex › media › 1916 › ta-113-the-regional … ·...

TA 11.3 Regional Water Grid

Technical Annex

September 2018 Version 1.0

2 TA.11.03 Regional Water Grid Technical Annex

Contents

Executive Summary ................................................................................... 5

Current Connectivity ................................................................................... 6

Phase 1: The Hampshire Grid and Area Reinforcement (by 2030) ............ 6

Phase 2: Regional Grid (by 2045) .............................................................. 9

Appendix 1: Strategic Maps ..................................................................... 12


Navigation: TA.11.03 – Regional Water Grid

Purpose:

This technical annex provides information to support proposals for the regional water grid

within the plan. It comprises part of the supporting evidence for chapter 11 Wholesale

Water.

The table below summarises the Ofwat tests that are addressed by the evidence presented in this Annex. Table 1 - Relevant Ofwat tests

Ref Ofwat test Comment

Primary Focus Areas

Securing long-term resilience – LR2

How well has the company objectively assessed the full range of mitigation options and selected the solutions that represent the best value for money over the long term, and has support from customers?

High-quality plan: An organisation-wide, integrated approach to appraising risks to resilience supported by strong evidence that takes suitably long-term views using a range of forward-looking appraisal techniques across key service areas. Effectively engage with customers on resilience in the round, including facilitating informed choices. Use innovative approaches to the appraisal of risks to resilience, supported by best practice techniques to understand and appraise uncertainty across the full range of pressures, from acute shocks to longer term chronic stresses. It should also consider hazards and threats, such as cyber security, flooding and disruptions to energy supplies. Include cross-references to changes in operational risk and planned levels of

The development of the regional water grid is a key enabler for securing resilient water supplies for our customers. The water grid not only allows us to make the best use of our own resources, but it facilitates trading of water between companies minimising the need to develop new sources throughout the south of England and facilitating the development of innovative collaborative new resources such as the new reservoir at Havant Thicket that we are developing with Portsmouth Water.


service, supported by strong evidence. Thoroughly appraise options for mitigating resilience presenting a full range of options as evidence that the plan will deliver the best value long-term options for customers. This will include utilising options beyond its boundary to mitigate risks in its own area (and also looking beyond its boundary to understand how it can support long-term resilience elsewhere). Ambitious and innovative plan: Strong evidence that innovative approaches will deliver sector-leading operational resilience including the role of partnership, use of markets, catchment management and other softer option in combination with fixed asset based solutions.

G

OC1 Delivering outcomes for customers

CMI1, CMI2

Targeted controls, markets and innovation


Executive Summary An increasing population and decreasing availability of water represents a substantial and

intensifying challenge for the south-east of England over the next 50 years.

These pressures not only put significant strain on our natural environment, but also impacts

our ability to provide a resilient water supply network for future generations.

We predict a supply/demand deficit across our region of 294 megalitres per day (Ml/d) by

2030, with a deficit of 188Ml/d in Hampshire alone1. Other companies in the region are also

similarly affected.

To respond to these challenges a paradigm shift is required in regional connectivity to

ensure water companies can not only be collaborative in building new resources but also be

able to share these across the south-east.

To achieve this shift, we are developing a Regional Water Grid, which will integrate all major

water sources through a network of strategic pipelines to ensure resources can be better

distributed across the south east region. This will lead to development of fewer new resource

schemes and optimise the amount of water taken from the environment, reducing the overall

impact of the water industry on the environment in the south-east. Through adding more

redundancy and being able to share water more effectively in emergencies (improved

response and recovery) the Regional Water Grid will make the south-east significantly more

resilient and ready for future challenges.

The Regional Water Grid will be developed over the next 25 years in conjunction with key

stakeholders, communities and industry strategy groups such as Water Resources South

East (WRSE). The Regional Water Grid will also be integrated with existing strategic

infrastructure such as the Wessex Grid and the Thames Water Ring Main to enhance the

resilience of both the south east and adjacent regions.

We envisage the Regional Water Grid being developed in 2 distinct phases:

Phase 1: The Hampshire Grid and Area Reinforcement (by 2030)

Phase 2: The Regional Grid (by 2045)

We will ensure the development of the grid aligns with the Government’s long-term

Environment Plan: A Green Future: Our 25 Year Plan to Improve the Environment (2018) in

delivering sustainable, clean and plentiful water.

The Regional Water Grid will align to our long-term objectives for demand management, in

particular Target 1002, and our long-term leakage target (to achieve a 50% reduction by

2050)3. This also aligns with our other key transformation programmes, in particular

Network 2030. Together with the development of the Regional Water Grid this will enable

the delivery of the key outputs in the National Infrastructure Commission (NIC) report:

Preparing for a drier future: England’s water infrastructure needs (2018) to make the south-

east of England resilient beyond 2050.

1 PR19 Data Tables WS4, WR6 and WR7 2 TA.11.WN01 Business Case - Supply Demand Balance 3 TA.11.WN04 Business Case - Water Treatment


Current Connectivity

Figure 1: Southern Water Strategic Network (2018)

As of 2020 there is limited connectivity across the south-east region. Figure 1 shows our

connectivity with the other companies in the region, this is described below:

Existing Connectivity:

A 10 Ml/d transfer from Gaters Mill (from Portsmouth Water) via Petersfield to

Hardham with a 5 Ml/d spur to Madehurst.

15 Ml/d from Gaters Mill into the Southampton trunk main network. This was

commissioned in 2018 and is the key first step in the development of a regional grid.

Numerous bulk exports to SEW, this includes major exports from Weirwood and from

Burham (totalling c25 Ml/d).

A single bulk import from Affinity into Thanet (5 Ml/d).

There is limited connectivity from Western Area to Central Area and no connectivity

to Eastern Area or Hastings.

There is therefore limited current regional connectivity and limited regional resilience. There

are also additional pressures in an increasing population and decreasing availability of raw

water. These pressures put significant strain on our natural environment and in our area we

predict a supply/demand deficit across the region of 294 megalitres per day (Ml/d) by 2030,

with a deficit of 188Ml/d in Hampshire alone. We have therefore considered how to increase

regional connectivity, increase resilience, and collaborate with other companies and share

resources.

Phase 1: The Hampshire Grid and Area Reinforcement (by 2030) Sustainability challenges will impact our Western Area first, this will reduce our dry year

critical period capacity in Hampshire by 188Ml/d.4 This equates to a loss of 76% of the


current 248Ml/d capacity. We are also investigating the need to reduce our abstractions in

Sussex, which could reduce the water available for use by up to 75Ml/d.

As agreed with the Environment Agency, we are reliant on drought orders and drought

permits to meet this deficit until our major investment proposals can be delivered in 2027.To

ensure we can meet this challenge we will develop the first part of our Regional Water Grid

in Hampshire (the Hampshire Grid), we will also reinforce parts of the central and eastern

area to add resilience and develop new resources to ‘plug’ into this more resilient network

architecture. Table 1 outlines all regional grid schemes and key resource developments

which integrate into the grid:

Table 1: Regional Grid Phase 1 Schemes (by 2030)

Map Number

Grid Component Year Component Area Capacity (Ml/d)

1 Increased transfer from PWC 2023 Hampshire Grid

Western 9

2 New bi-directional transfer So'ton to Winchester

2023 Hampshire Grid

Western 50

3 New bi-directional transfer Winchester to Andover

2023 Hampshire Grid

Western 25

4 Patching WSW 2023 Network 2030

Central 11

5 Thanet North WSW 2023 Network 2030

Eastern 24

6 Enhanced Broadlands Transfer 2024 Regional Western 2

7 SEW Transfer to Wingham 2025 Regional Eastern 5

8 Brighton East WSW 2025 Network 2030

Central 24

9 New Transfer with Bournemouth

2027 Hampshire Grid

Western 20

10 Fawley Desalinaton 2027 Hampshire Grid

Western 75

11 Ford Re-Use 2027 Regional Central 20

12 Shoreham Desalination 2027 Regional Central 10

13 Aylesford Re-Use 2027 Regional Eastern 18

14 Sandown Re-Use 2027 Regional Western 8.5

15 Selling to Fleet Transfer Upgrade

2027 Regional Eastern 5

16 Hardham Winter Transfer Phase 2

2027 Regional Central 2

17 Knighton B WSW 2028 Network 2030

Western 24

18 Havant Thicket Reservoir 2029 Hampshire Grid

Western 21

19 New bi-directional transfer Andover to Kingsclere

2030 Hampshire Grid

Western 10

Totals 366


Figure 1 show a schematic representation of the proposed new pipelines and resources

which will be developed by 2030.5

Figure 1: Southern Water Strategic Network (2030)6

Summary of the Hampshire Grid7

Construction of the first phase of the Hampshire Grid by 2023. This includes

increasing our existing bulk supply agreement with Portsmouth Water from 15Ml/d to

24Ml/d (1) and included pipelines from Southampton to Winchester and from

Winchester to Andover (2 and 3).

By 2024 we will enhance the Broadlands Transfer to ensure that we can move more

water between our Testwood and Timsbury Water Supply Zones (6).

A new 20 Ml/d transfer pipeline will be built between South West Water’s network

and our Rownhams Water Service Reservoir in Southampton (9).

With the major pipelines in place and the first phases of the Hampshire Grid

complete. We will then begin to bring major new resources on-line. This includes the

Havant Thicket Reservoir Resilience Project (operational by 2029). This involves the

construction of a new winter storage reservoir – the first major strategic water

resource in the South East for decades and a major collaborative venture between

Southern Water and Portsmouth Water developed through the WRSE group to

provide resilient water supplies (18).8

We will bring another new resource, the 75 Ml/d Fawley Desalination Plant in

Southampton on-line in 2027 and connect into the Regional Water Grid (10).

We will also build a 8.5 Ml/d water reuse scheme at Sandown on the Isle of Wight.

This return treated water upstream of existing abstraction at Sandown (14).

We will complete a new 24 Ml/d Water Supply Works (Knighton B) in 2028 to replace

the existing Sandown Water Supply Works and two other works as part of our

5 Numbering is as per Table 1. 6 Appendix 1 provides a larger regional map for ease of reference. 7 Numbers in red refer to the pipeline numbering in Figure 1. 8 Please refer to TA.11.WR01, TA.11.WN02 and T.A.11.WN04 for all scheme details.


Network 2030 initiative (17). These schemes are key to the development of the

southern part of the Hampshire Grid and increasing resilience on the Isle of Wight.

By 2030 we will have completed the Hampshire Grid with further extensions of the

grid from Andover to the Kingsclere area (19).

Upon completion of the Hampshire Grid we will have significantly increased the resilience of

our water supply network, as well as increasing the resilience of other water companies and

lay the foundations for the wider regional water grid. The Hampshire Grid represents a

significant proportion of our overall totex investment totalling £200m in pipelines and over

£300m in new resources invested from 2020 to 2030 to create a resilient water supply

network.

Summary of the Central and Eastern Area Reinforcement

As part of our Network 2030 initiative we will build 3 new Water Supply Works (with a

total capacity of ~ 60 Ml/d) in Thanet (5), Brighton (8) and Worthing (4) by 2025. This

will increase resilience in these Water Supply Zones and will become a key

component of the Regional Water Grid.

We will construct two new bi-directional transfers. One from South East Water to our

Wingham Water Supply Works in Thanet by 2025 (7) and a new reinforcement main

(to increase transfer capacity) between our Medway and Thanet Supply Zones (15).

We will also build a 18 Ml/d water reuse scheme at Aylesford in Kent, this will return

flow upstream of existing abstraction at Burham. (13).

In the Brighton and Worthing Zones we will construct new pipelines and new

resources. This will include a new strategic transfer from our Hardham Water Supply

Works to reservoirs in central Brighton (16), the development of a new 10 Ml/d

desalination plant at Shoreham (12) and 20 Ml/d water re-use scheme at Ford to

return flow upstream of existing abstraction at Hardham Water Supply Works (11).

These initial schemes are key for the further development of the Regional Water Supply

Grid.

Phase 2: Regional Grid (by 2045) Beyond 2030 we will further develop the Regional Water Grid to ensure the whole of the

south-east has a resilient water supply network for the future. This section outlines a set of

schemes which would further integrate our network with neighbouring companies and then

to integrate with existing strategic infrastructure such as the Wessex Grid and the Thames

Water Ring Main to enhance the resilience of both the south east and adjacent regions. We

intend to further develop these schemes with other companies and key stakeholders over

the course of AMP7 with the aim of creating a single master plan for a Regional Water Grid

to 2045 and beyond.

These schemes are set out in Table 2.

Table 2: Regional Grid Phase 2 Schemes (by 2045)

Number Grid Component Year Component Area Capacity (Ml/d)

20 Lewes/Brighton East to SEW Barcombe Link

2035 Regional Link Central 50

21 Hastings to SEW Arlington/Hazards Green


22 Central to Eastern Spine 2035 Regional Link Central 75


23 Central Reinforcement Spine


24 Thames Ring Main spur to Hampshire Grid

2045 Inter-Regional Multiple 50

25 Wessex Grid to Hampshire Grid


26 Abingdon to Hampshire Grid and Thames Ring Main


27 SEW to Hampshire Grid 2045 Inter-Regional Multiple 50

28 Hampshire Grid to Central Link Main


29 Central Grid to Affinity to Thames Ring Main


30 Hampshire Grid to Central Reinforcement Main


Totals 300

We anticipate that the regional link schemes (20 to 23) will need to be in place by 2035, this

will provide vital connectivity between our Western/Central Area and our Eastern Area. It will

also ensure that our water supply areas are linked with other companies

Figure 2: Southern Water Strategic Network (2045)9

This provides a base to develop inter-regional schemes (24 to 30) which we envisage being

developed in the 2040’s. These schemes will link the Regional Water Grid to existing grid

infrastructure such as the Wessex Grid and the Thames Ring Main. This will also integrate

major future resource developments such as Abingdon Reservoir into the Grid and ensure

these new resources can be shared across the south-east.

9 Appendix 1 provides a larger regional map for ease of reference.


By 2045 this will lead to completion of the Regional Water Grid, integrating all major water

sources through a network of strategic pipelines to ensure resources can be better

distributed across the south east region. This will lead to development of fewer new resource

schemes and optimise the amount of water taken from the environment, reducing the overall

impact of the water industry on the environment. The Regional Water Grid will make the

south-east significantly more resilient through adding more redundancy (less single points of

failure) and being able to share water more effectively in emergencies (improved response

and recovery).

Beyond 2045 there a likely to be further opportunities for inter-regional grid development.

Proposed multi-amp projects such as the Anglian Grid and the UU (Cumbrian) Grid will

mean a number of regional grids will be in existence by 2050. The next logical step will be to

link these regional grids together and potentially forming a single national grid10. We intend

to be at the forefront of grid development for decades to come and to work with government,

community stakeholders and other companies to work towards a more resilient water future.

10 Subject to further customer acceptability testing


Appendix 1: Strategic Maps

ta 11.3 regional water grid technical annex › media › 1916 › ta-113-the-regional … ·...

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