Water Resources
Management
Plan
Yorkshire Water Services Ltd
Contents
Contents ... 3
List of figures ... 5
List of tables ... 5
7
Baseline Supply Demand Balance ... 7
7.1
East Surface Water Zone supply demand balance ... 7
7.2
Grid Surface Water Zone supply demand balance ... 7
7.3
Options appraisal ... 9
7.3.1
Types of options available to meet the deficit ... 10
7.3.2
Development of potential options ... 11
7.3.3
Water trading options ... 11
7.3.4
Environmental, social and carbon costs ... 12
7.3.5
Optimisation model ... 13
7.3.6
WRAPsim modelling of options ... 14
7.3.7
Impact of climate change on options ... 14
7.4
Grid Surface Water Zone least cost solution... 14
7.5
SEA and Habitats Regulation Assessment... 16
7.6
Customer views on options ... 22
7.6.1
Willingness to pay surveys ... 22
7.6.2
Customer Challenge Group ... 23
7.7
Grid Surface Water Zone preferred solution ... 24
7.7.1
SEA of preferred solution ... 28
7.7.2
SEA cumulative impact assessment ... 31
7.7.3
Mitigation and monitoring ... 31
7.7.4
Habitats Regulations Assessment and Water Framework Directive
Assessment ... 32
7.7.5
Customer preferences to preferred solution ... 35
7.7.6
Final planning headroom assessment ... 36
7.8
Grid Surface Water Zone preferred solution sensitivity testing ... 36
7.8.1
Sensitivity testing scenario solutions ... 38
7.8.2
Management of risk and uncertainty ... 39
8
Final Planning Scenario Supply Demand Balance ... 45
8.1
Future leakage targets ... 47
9
Bibliography ... 49
10
Glossary of terms ... 52
11
Appendices ... 54
List of figures
Figure 7.1: Grid SWZ baseline forecast supply demand balance ...8
Figure 7.2: Options appraisal process ...9
Figure 7.3: Grid SWZ least cost solution ...15
Figure 7.4: Integration of SEA, HRA and WFD in the WRMP Process ...17
Figure 7.5: Grid SWZ preferred solution for the baseline dry year annual average scenario ...27
Figure 7.6: Grid SWZ optimised solution for the selected target headroom scenario ...41
Figure 7.7: Grid SWZ optimised solution for the increased target headroom profile scenario ....42
Figure 7.8: Grid SWZ initial optimised solution for the maximum climate change scenario ...43
Figure 7.9: Grid SWZ final optimised solution for the maximum climate change scenario ...44
Figure 8.1: Grid SWZ preferred solution supply demand balance ...46
Figure 8.2: Baseline and final planning scenario regional greenhouse gas emissons ...48
List of tables
Table 7.1: Summary of the Grid SWZ supply demand deficit across the planning period ...8Table 7.2: SEA topics and objectives ...18
Table 7.3: SEA outputs of Grid SWZ least cost solution ...21
Table 7.4: Summary of option changes following least cost solution ...25
Table 7.5: Start date and yield of schemes to deliver the Grid SWZ preferred solution ...26
Table 7.6: SEA outputs of Grid SWZ preferred solution ...30
Table 7.8: Solution sensitivity testing scenarios ...37 Table 8.1: Final planning supply demand surplus...45 Table 8.2: Future leakage targets ...47
7 Baseline Supply Demand
Balance
1. The previous chapters describe how we develop a baseline forecast for supply and demand for each resource zone. Supply refers to the total water available for use (line 13BL in the water resources planning table WRP1 BL Supply). Demand refers to the sum of distribution input and target headroom. Target headroom is added to distribution input to ensure supply can meet a demand greater than the forecast distribution input. This allows for uncertainties in the components that make up the supply demand balance and gives us greater confidence we can meet our chosen level of service.
2. The supply forecast is compared against demand to determine if we have sufficient supply to meet demand over 25 years. If the supply demand balance shows there is a deficit we will need to invest in schemes to either increase supply or decrease demand to ensure we can meet our chosen level of service in the future.
7.1 East Surface Water Zone supply demand balance
3. A supply demand appraisal has been undertaken for the East SWZ dry year annual average planning scenario and the critical period scenario. For both planning scenarios there is a surplus throughout the planning period.
4. In the dry year annual average scenario, supply is 4.99Ml/d or more above demand for each year of the planning period.
5. The critical period scenario also shows a surplus throughout the planning period. The surplus is no less than 2.84Ml/d throughout the 25 years. This surplus is less than the dry year annual average, as demand increases in this scenario to represent the peak period.
6. This zone has a large surplus in both scenarios, therefore no investment is required to meet the level of service in the East SWZ over the 25 year planning period.
7.2 Grid Surface Water Zone supply demand balance
7. The baseline supply demand balance for the Grid SWZ dry year annual average scenario is shown in Figure 7.1. This shows a substantial deficit which is increasing over the planning period as the forecast supply cannot meet the forecast demand.
8. The deficit is the result of a continuing decline in water available for supply, due to the impacts of climate change and sustainability reductions. Climate change is forecast to create a year on year incremental reduction in supply. A 2.0Ml/d sustainability reduction is applied in 2013/14 and a 0.7Ml/d sustainable reduction applied in 2017/18.
9. Demand does not change significantly over the planning period. Following an initial decline, it increases steadily to 2.5Ml/d above the base year demand by 2039/40.
Figure 7.1: Grid SWZ baseline forecast supply demand balance
10. The Grid SWZ supply demand deficit starts in 2018/19, when demand, including target headroom, is 2.67Ml/d greater than supply. By 2027/28 supply is below demand and no headroom is available. The deficit continues increasing to 108.65Ml/d by 2039/40. A summary of the deficit is given below in Table 7.1.
Table 7.1: Summary of the Grid SWZ supply demand deficit across the planning period 1200 1220 1240 1260 1280 1300 1320 1340 1360 1380 1400 Ml/d
Water available decreasing due to climate change
Deficit below headroom from 2018/19
Demand + headroom
Demand
Total WAFU Deficit below demand
from 2027/28 Planning scenario 2 0 1 5 /1 6 2 0 1 6 /1 7 2 0 1 7 /1 8 2 0 1 8 /1 9 2 0 1 9 /2 0 2 0 2 0 /2 1 2 0 2 5 /2 6 2 0 3 0 /3 1 2 0 3 5 /3 6 2 0 3 9 /4 0
Grid SWZ dry year
7.3 Options appraisal
11. As a deficit has been identified in the Grid SWZ, we need to invest in schemes that will either reduce the forecast demand or provide additional supply in the future. There are numerous schemes that we could implement. To select an appropriate solution to the deficit we considered the available options and determined which were feasible. We then carried out an options appraisal as summarised in Figure 7.2.
Figure 7.2: Options appraisal process
12. The options appraisal determines a solution that is sustainable against infrastructure limitations, environmental impacts and our customers’ preferences. Infrastructure limitations are identified through our WRAPsim model.
13. The options appraisal initially determines the lowest cost solution, including monetised environmental, social and carbon costs, as well as economic costs. We have an optimisation model to determine the least cost solution, based on net present costs.
14. We assess the least cost solution against our customers’ preferences and the environmental, social and economic factors that cannot be monetised. These non-monetised costs are determined through a Strategic Environmental Assessment (SEA) that considers the environmental and social impacts of each of the available options. 15. To take account of non-monetised factors we may need to constrain out some of the
feasible options or delay/bring forward certain schemes. We then re run the optimisation model to provide a solution that is our preferred solution.
The steps involved in moving from our least cost solution to our preferred solution to meet the Grid SWZ deficit are outlined below:
Step 1: Run the optimisation model with all feasible options included.
Step 2: Determine the yield availability of resource options in our WRAPsimdeployable output model. This is carried out after an initial run of the optimisation model as the cumulative impact of the solution can provide different yields to those provided by the individual options.
Step 3: Re run the model with option yields reduced according to those determinedin step 2. This provides the least cost solution to the supply demand deficit.
Step 4: Review the least cost solution against the SEA to identify options thatshould be constrained out to minimise the impact of the solution on the environment or society.
Step 5: Determine if the least cost solution meets customers’ preferences. It willnot always be possible to find a solution that all our customers and stakeholders agree to be optimal. However, if the solution contradicts all customer preferences we will amend the feasible options to readdress the balance.
Step 6: Rerun the optimisation model to determine a solution that provides bestvalue for the environment, customers and stakeholders and secures supply over the planning period. This is our preferred solution to the supply demand deficit. It may be necessary to repeat steps 4 to 6 until we have a solution that meets all our objectives.
16. The following sections describe the options appraisal process in more detail;
7.3.1 Types of options available to meet the deficit
17. We have numerous options available to meet a supply demand deficit. These can be grouped into four categories:
Resource management - options which increase deployable output, such as newreservoirs or resource transfers.
Production management - options targeted at activities between abstraction anddistribution input.
Distribution management - options targeted at activities between distribution input
Customer side management - options affecting customers’ use and supply pipelosses.
7.3.2 Development of potential options
18. We have a range of resource schemes available as options to meet a supply demand deficit. A workshop was held in April 2012 to bring together Yorkshire Water staff with knowledge of our supply system and operations. In this workshop we reviewed the WRMP 2009 list of options and identified new potential schemes.
19. During the workshop we reviewed the technical, environmental, carbon and social attributes of each option. The technical attributes considered were yield increase/demand decrease; construction/delivery costs; time to implement; and asset life of infrastructure. 20. The information collated in the workshop was used to determine which schemes were
feasible options and constrain out those that were not suitable. The information was used to assess the schemes against the following criteria:
Does the option address the problem?
Does the option avoid breaching any unalterable constraints?
Is the option promotable/does it meet regulatory and stakeholder expectations?
Is the risk of the option failing acceptable?
Should the option be taken through to the constrained list?21. Appendix A gives the unconstrained list of options, i.e. all the potential options considered; and Appendix B gives a brief description of the feasible options. The next step was to determine build costs and operating costs for each feasible options.
22. Where financial cost data was already available for options, we applied inflation using the Retail Price Index (RPI). Arup consultants were commissioned to assess and cost the options for which costs were either not available or there was evidence to suggest previous costs needed revising.
7.3.3 Water trading options
23. In accordance with the Environment Agency et al. (2013) Water resources planning
guideline, water companies should consider water trading options in their water resource
management plans. This could be with other water companies or third parties.
24. During the pre-consultation phase we met with our neighbouring water companies - Northumbrian Water, United Utilities, Severn Trent Water and Anglian Water - to discuss potential water trading opportunities. These discussions included both importing and exporting water.
25. Our discussion with Northumbrian Water identified two potential imports with variations on how the water could be transferred. There are no options available for us to export water to Northumbria Water.
26. Our previous water resources management plans have included an option for Northumbrian Water to provide us with water that it is licenced to abstract from the River Tees. Our discussions with Northumbrian Water for this plan confirmed it has sufficient spare capacity to provide up to 140Ml/d from the River Tees to a treatment works near York. This export could be transferred either via a pipeline or via a combination of pipeline and rivers.
27. Additional options were identified to import 15Ml/d from Northumbrian Water to the Yorkshire Dales area in our Grid SWZ. There are two alternatives to this scheme, one would transfer raw water and the other treated water. The source of this export would also be the River Tees. These schemes could be delivered in combination with an export to the York water treatment works but the combined yield would be constrained to 140Ml/d.
28. Our meeting with United Utilities identified one option for us to export water to its regions and three options for us to import water from United Utilities. The export would be a release from one of our reservoirs to the Huddersfield Canal for United Utilities to abstract.
29. The three imports include a release from one of United Utilities reservoirs to the Rochdale Canal, connecting an existing raw water pipeline to deliver water to North Yorkshire and installing a clean water pipeline transfer, also to North Yorkshire.
30. Our meeting with Severn Trent Water identified one export and no imports. Our export would transfer 20Ml/d from South Yorkshire to Severn Trent Water via a new pipeline. Discussions with Anglian Water did not identify any imports or exports.
31. An outline of all feasible imports and exports is provided in Appendix B. We have not identified a bulk transfer as part of our preferred solution and Severn Trent Water and United Utilities have informed us they do not require us to export to their supply areas. 32. To determine potential third party transfers we obtained details of unused/partially used
and recently revoked groundwater abstraction licences in the Yorkshire region from the Environment Agency. We assessed the feasibility of each licence based on the potential to use the yield in supply. This was limited by the capacity to treat the water and the water quality, i.e. a number of sites were in areas where we had previously closed sources due to poor water quality or mained out the supply.
33. From this list we identified four recently revoked licences that we could use for supply. These are included in our feasible options list (see Appendix B).
7.3.4 Environmental, social and carbon costs
34. This section describes the methodology to calculate monetised costs for the environmental, social and carbon impacts of the feasible options. The non-monetised environmental and social costs are determined in a Strategic Environmental Assessment, as described in Section 54.
35. We derived carbon, environmental and social costs for all feasible options through a desktop assessment. We calculated the costs for new schemes and reappraised the costs for schemes included in the WRMP 2009 options appraisals.
36. The Water resources planning guideline, (Environment Agency et al., 2013) recommends using the Risk and Policy Analysts Ltd (RPA) methodology, Benefits Assessment
Guidance, (Environment Agency, 2012) to estimate the environmental and social costs
for the options. The guidelines also recommend referring to the Economics of Balancing
Supply and Demand Methodology (UKWIR, 2003) guidelines for the inclusion of
environmental and social costs. The RPA methodology is an updated version of the methodology recommended in the UKWIR guidance. We inflated all costs from this report to current prices using the retail price index (RPI).
37. We based the atmospheric carbon impact of each potential solution on the Traded Cost of Carbon, as recommended in the planning guideline. However, we derived the operational impacts from the A Framework for Accounting for Embodied Carbon in Water
Industry Assets (UKWIR, 2012) and derived the embodied carbon emissions from a
Yorkshire Water based methodology. This methodology will align with the forthcoming UKWIR methodology for embodied carbon.
38. We developed social costs in relation to traffic from a Yorkshire specific study Lane
Rental Charging – A Way Forward (Stone and Webster, 2002).
39. Appendix D gives the environmental, social and carbon costs for the Grid SWZ options.
7.3.5 Optimisation model
40. We use an optimisation model to calculate the least cost solution. Since the WRMP 2009 was published a new optimisation model has been developed by Hartley McMaster Ltd on behalf of Yorkshire Water.
41. The optimisation model takes account of all feasible supply and demand options and optimally schedules investment to meet the projected deficit at minimum net present cost (NPC). In accordance with Environment Agency guidelines, all costs are discounted over 80 year and inflated by 4.5%. Further information on the model constraints and assumptions is provided in Appendix A.
42. The model is populated with the cost data described above and all other parameters such as time to implement, yield capacity, first practical year available, interdependencies and mutual exclusions are specified for each option.
43. The economic model utilises a linear/integer programming approach, as described in the UKWIR report, The Economics of Balancing Supply and Demand (Environment Agency and UKWIR, 2002). This is an alternative technique to the average incremental social cost (AISC) approach for option selection.
44. Where there are only variable costs and no option dependencies, the AISC and integer programming methodologies will give the same solution. If there are dependencies between options, the AISC approach may not give the optimal ranking without fine tuning, which may result in an alternative solution being overlooked.
45. The integer programme technique selects a schedule of options that will, in aggregate, meet any projected deficit in each year, from the base year to the end of the 25 year planning horizon. The selected schedule of options has the least net present value (NPV).
46. The output from the model includes AIC (average incremental cost), AISC and NPV costs, as defined in The Economics of Balancing Supply and Demand (Environment Agency and UKWIR, 2002), based on the output of the scheme.
7.3.6 WRAPsim modelling of options
47. In order to cost the schemes for the Grid SWZ, each feasible supply side option is assigned a yield that could be available from implementing the individual scheme. However, the final yield of each scheme is influenced by the supply demand balance scenario and the other options selected. WRAPsim modelling is used to determine the option yield, taking into account the hydrological conditions and infrastructure constraints of the Grid SWZ at the given deficit.
48. We cannot carry out the WRAPsim modelling of options until after the supply demand deficit is known. For example, the River Ouse Raw Water Transfer option has a maximum capacity of 60Ml/d but the amount taken will depend on the available treatment capacity at the receiving water treatment works. We cannot take 60Ml/d if the water treatment works does not have this spare capacity. However, we cannot determine the yield the option can provide until the impacts of climate change and sustainability reductions are known, as these factors will impact on the volume of water available to treat at the treatment works.
49. WRAPsim also needs to consider the cumulative impact of the options selected. The yield of the scheme may be dependent on the other schemes selected, particularly if the yields are to be treated at the same treatment works.
50. An initial run of the optimisation model with the schemes at their maximum capacity provided the schemes to be considered in WRAPsim in correlation with each other. The yields of options in the optimisation model are then revised to include any reductions due to hydrological and infrastructure constraints.
7.3.7 Impact of climate change on options
51. The effect of climate change on individual selected options was assessed prior to inclusion in the optimisation model. After the change in groundwater climate change assessment for the WRMP described in Part 1,Section 3.7, none of our options were thought to be directly affected by climate change.
52. The options in our preferred solution have been modelled with our median climate change scenario to ensure that the options are robust to climate change. This is fully described in the report Technical submission: Climate Change Effect on Deployable Output.
7.4 Grid Surface Water Zone least cost solution
53. The optimisation model was run to determine the least cost solution for meeting the supply demand deficit in the Grid SWZ over the 25 year planning period. This output is shown in Figure 7.3.
54. The least cost model run provides a solution with 13 demand reduction options and five schemes to increase supply. The options will be implemented over the 25 year planning period. The first six options selected are active leakage control in 5Ml/d phases to provide a total of 30Ml/d demand reduction before implementation of R6 South Yorkshire Groundwater Option 1 in year 10. These options provide sufficient yield to meet the deficit in the next two AMP periods, up to 2024/25.
55. Going forward a combination of further demand reduction and resource options are brought in as the deficit increases. The largest scheme selected is the D20 Ouse Raw Water Transfer, which delivers 40Ml/d in 2027/28.
56. The model selects the least cost options for the 25 year planning period. In some instances it can be more economical to build a scheme with a large yield which provides the zone with a surplus for a number of years, such as D20 Ouse Raw Water Transfer. 57. The next stages of the options appraisal take into account non-monetised factors that
influence the solution. We aim to ensure our plan is not creating an unacceptable risk to the environment, driving unnecessary investment or implementing options that oppose our customers’ preferences.
7.5 SEA and Habitats Regulation Assessment
58. The non-monetised environmental, social and carbon impacts of each option have been considered in a Strategic Environmental Assessment (SEA). The full output of the SEA is provided in an Environmental Report, which is published on our website alongside this document.
59. We have reviewed all available guidance; Strategic Environmental Assessment and
Habitats Regulation Assessment Directive (UKWIR, 2012) and A Practical Guide to the
Strategic Environmental Assessment (ODPM, 2005), and determined that the WRMP
falls under the SEA. This is because the options for the plan include schemes which require Environmental Impact Assessment (EIA), for example pipeline installation schemes.
60. The SEA and the WRMP options appraisal have been informed by a Habitats Regulations Assessment (HRA) Screening Report. A WFD Assessment was also carried out to inform the SEA and assess the impact of the least-cost plan on WFD requirements for no deterioration to waterbodies. The SEA, HRA and WFD assessments have influenced the options appraisal to determine a preferred solution that reduces the risk of detrimental impact to the environment. Figure 7.4 outlines the process for integrating the SEA and HRA into the options appraisal.
Figure 7.4: Integration of SEA, HRA and WFD in the WRMP Process
61. The SEA can add value to the options appraisal process by identifying a wider range of impacts that cannot be monetised. It considers both adverse and beneficial potential environmental and social effects of feasible options, and identifies the cumulative effects of a supply demand solution.
62. A cumulative, or in-combination, assessment has been undertaken on the preferred solution. This involved examining the potential impacts of each of the water resources management options in combination with each other, as well as in combination with the implementation of other relevant plans and programmes.
63. We have ensured the environmental and social impacts are not double-counted in both the monetisation process and the SEA, as this could potentially skew the options and programme appraisal process.
64. The overall findings of the SEA describe the extent to which objectives for eight environmental topics are met by each of the WRMP options. Table 7.2 lists the topics and associated objectives.
SEA Topic Ref. SEA Objectives Biodiversity,
flora and fauna
1.1
To protect and enhance biodiversity, ecological functions, capacity, and habitat connectivity within our supply and source areas.
1.2 To strengthen the connections between people and nature and to realise the value of biodiversity.
Population and human health
2.1
To improve human health and well-being of the area, improve access to recreation and the environment, and reduce inequalities.
Material assets and resource use
3.1
To reduce, and make more efficient, the domestic, industrial and commercial consumption of resources, minimise the generation of waste, encourage its re-use and eliminate waste sent to landfill.
Water
4.1 To maintain or improve the quality of rivers, lakes, groundwater, estuarine and coastal waterbodies.
4.2
To ensure appropriate and sustainable management of abstractions. Safeguarding reliable, resilient and sustainable water resources for people, economy and the environment. 4.3 To reduce and manage flood risk.
4.4 To increase awareness of water sustainability, its efficient use and the ecosystem functions which rely on water resources. Soil, geology
and land use 5.1
To protect and enhance geology, the quality and quantity of soils and promote a catchment-wide approach to land management. Air and
climate
6.1 To reduce air pollutant and greenhouse gas emissions.
6.2 To adapt and improve resilience to the threats of climate change. Archaeology
and cultural heritage
7.1 To conserve and enhance the historic environment, the heritage assets therein and their setting.
Landscape and visual amenity
8.1
To protect and enhance the quality of, and improve access to, designated and undesignated landscapes, townscapes and the countryside.
Table 7.2: SEA topics and objectives
65. A nine point impact assessment scale was used, using the effect categories: major adverse; moderate adverse, minor adverse; neutral/negligible; mixed; uncertain; minor beneficial; moderate beneficial and major beneficial. This report considers the outputs of the SEA on the least cost solution and the preferred solution. The SEA outputs for all the feasible options can be found in the SEA Environmental Report.
66. Table 7.3 provides a summary of the SEA outputs for the least cost solution. The majority of impacts are negligible but there are a number of moderate and minor adverse impacts, and there is one solution that has a major adverse impact in relation to one SEA objective.
67. To reduce the impact of our solution on the environment, we have chosen to remove the R6 South Yorkshire Groundwater Option 1 selected in the least cost solution from our feasible options This scheme has a risk of unsustainable impacts on parts of the Sherwood Sandstone aquifer.
68. The South Yorkshire Groundwater Option was removed as it is highlighted by the SEA to have a major adverse impact on one of the objectives. This was particularly driven by the poor quantitative and chemical status classification for the groundwater body as identified through the WFD option assessment process. This option involves installation of new infrastructure to link an existing group of licensed boreholes in the South Yorkshire area. The new infrastructure would allow the yield from the boreholes to be transferred elsewhere in the Grid SWZ and increase utilisation of the licensed source.
69. The boreholes abstract from the Sherwood Sandstone aquifer, in an area that is classed as over licensed by the Environment Agency Catchment Abstraction Management Strategy (CAMS). The area is classified as medium stressed in the Water Stressed
Areas – Final Classification (Environment Agency and Natural Resources Wales, 2013)
and has previously been classed as seriously stressed. There is a risk we could have an adverse impact on the environment if we were to increase our abstraction in this area. There is also a risk that the Environment Agency could revoke some of our existing permitted abstraction volume.
70. Based on the SEA and the over licensed status, we have chosen to remove this scheme from the feasible options available in the optimisation model. This is to avoid any potential major impacts on the environment as highlighted by the SEA and WFD assessment, and to avoid investing in new infrastructure that could be redundant if the licence is reduced in the future.
71. It is not practical to constrain out all schemes where there are potential negative impacts, as the remaining schemes would not meet the deficit and the cost would be disproportionately high. For this plan we have chosen to constrain out options the SEA classifies as having a major adverse impact on the environment. We have also reviewed the SEA results of all the selected options to consider the actions we can take to mitigate the environmental and social impacts. If the SEA highlights an adverse impact that is not classed as major adverse but presents an impact that is disproportionate to the yield gain or a risk that could increase in the future, we remove the scheme from the feasible options list.
72. The optimisation model selected R12 East Yorkshire Groundwater Option 1 as part of the least cost solution. This scheme is similar to R6 as it involves installing new infrastructure to enable existing underutilised licence capacity to be transferred elsewhere in the Grid SWZ. The licences are from the Sherwood Sandstone aquifer, but the SEA for this option does not raise major adverse impacts, as for R6.
73. Minor adverse effects were assigned to the scheme, taking account of the good status of the Aire and Don groundwater body and the fact that the scheme involves no increase to existing abstraction licence volumes. There would be no deterioration to the WFD status as a consequence of this scheme. The remaining negative impacts of R12 identified in the SEA are construction related and of a temporary nature only. The minor temporary adverse effects relating to the construction of the pumping station and pipeline can largely be mitigated at relatively low additional cost.
74. For the reasons outlined above, we do not associate the same risks as R6 with the R12 East Yorkshire Groundwater Option 1 scheme and have not constrained it out of the feasible options.
75. The SEA and WFD assessment have identified the R49 East Yorkshire Groundwater Option 2 scheme could have potential moderate impacts on the environment. This scheme plans to increase our use of an existing abstraction licence that we are currently underutilising due to water quality issues.
76. The boreholes associated with this scheme abstract from the Sherwood Sandstone aquifer and within a WFD groundwater body that is classified as having poor chemical status and poor status in relation to saline intrusion due to depressed groundwater levels. Although the abstraction would be within existing abstraction licence limits, the increase in actual abstraction associated with the scheme could have a moderate adverse effect on groundwater quality.
77. The East Yorkshire Groundwater Option 2 scheme involves relocating an unused borehole previously used to abstract from this source to higher ground, where the risk of saline intrusion will be largely reduced. We would monitor the water quality of the source and stop abstracting if chloride was detected, then start again once levels had recovered. Due to these mitigation measures we will continue to include this scheme as a feasible option.
78. Appendix 14 of the Water resources planning guideline (Environment Agency et al., 2013) recommends water companies include the net impacts of the solution on waterbody status under the WFD in the environmental and social assessment. We have assessed the impacts of the preferred solution on the WFD in Section 7.7.4. and provided a WFD assessment report to the Environment Agency.
Option Category Schem e Ref. P o p u la tio n a n d h u m a n h e a lth M a te ri a l a s s e ts a n d r e s o u rc e u s e S o il, g e o lo g y a n d la n d u s e A rc h a e o lo g y a n d c u ltu ra l h e ri ta g e L a n d s c a p e a n d v is u a l a m e n ity 1.1 1.2 2.1 3.1 4.1 4.2 4.3 4.4 5.1 6.1 6.2 7.1 8.1 Customer
conservation C1a (i) + N N + N + N ++ n/a - N n/a n/a
---Major adverse
Leakage D1a to D1g + N - M + ++ N ++ N - + N N -- Moderate
adverse D2a to D2e -Minor adverse N Negligible Internal Transfer D20 - N - - - - N N - - + N N U Uncertain
Groundw ater R6 N N - N -- --- N N N - N N - M Mixed
Groundw ater R9 - N N N N N N N N N N N N + Minor
benefits
Groundw ater R12 N N - N - - N N N - N N - ++ Moderate
benefits
Groundw ater R49 -- N - N -- -- N N N - N N N +++ Major
benefits Key Schem e Nam e + SEA Topic B io d iv e rs ity , flo ra a n d f a u n a W a te r A ir a n d c lim a te
Corresponding SEA Objective Num ber
Business customer audits and retrofit one off Active Leakage Control in DMAs
Leakage Pressure management N N N N N N N
Ouse Raw Water Transfer
+ N + N +
South Yorkshire Groundw ater Option 1 North Yorkshire Groundw ater East Yorkshire Groundw ater Option 1 East Yorkshire Groundw ater Option 2
7.6 Customer views on options
79. We carried out research into customer preference and prioritisation of the different investment options available.
80. A two stage approach using qualitative and quantitative research was used. An exploratory, qualitative phase was used to refine the options to ensure they were understood by customers, and the quantitative phase was used to establish which options consumers preferred.
81. For the qualitative research, four discussion groups were carried out at two separate locations (Leeds and Bridlington). To cover the key demographics of Yorkshire the groups were selected to be representative of factors such as socio-economic profile, age, metered/unmetered supply and urban/rural location.
82. In addition, ten face to face interviews were conducted with businesses. The business selected were a sample of small, medium and large water volume users. 83. To establish the investment options consumers preferred, and why, 1000 online
quantitative interviews were conducted with domestic customers. All participants were responsible (either fully or partially) for paying the water bill and quotas were placed on region, socio-economic group, age and gender to ensure a sample representative of our customers.
84. Customers were asked to rate a range of options before and after being provided with information on the cost, environmental impact and security of the yield for each option.
85. Initially customers’ preference was for mains replacement and leakage reduction. Priority was also given to schemes such as reservoir de-silting, water efficiency and supply pipe renewal.
86. When provided with cost, environmental impact and yield security information, preference was for leakage reduction, metering and water mains replacement. 87. In both the qualitative and quantitative research preference was towards options that
saved water. Options that increase available supply were less attractive to customers due to a perceived negative environmental impact.
88. Business customers also preferred leakage reduction, mains replacement and metering over the other options presented. The prioritisation was to use existing water supplies more efficiently and to conserve existing supplies before increasing available supply.
7.6.1 Willingness to pay surveys
89. In addition to customer preferences from the options survey, we must consider customer views expressed through our willingness to pay survey (WTP). Following the guidelines Carrying Out Willingness to Pay Surveys (UKWIR, 2011) we asked a
sample of customers for their preferences to a change in levels of service, including security of supply. Security of supply was presented as frequency of temporary use bans/hosepipe bans.
90. Qualitative and quantitative surveys were carried out as part of the PR14 WTP survey. The quantitative survey was completed by 1,200 domestic customers at 20 locations across Yorkshire. Information was collected through door to door interviews lasting approximately 40 minutes. We also collected quantitative information from 500 business customers through telephone conversations where discussion information was sent in advance by email or post.
91. Customers were asked their preferences for:
Maintaining the current level of service for 1 temporary use ban in 25 years
Improving the level of service to1 temporary use ban in 35 years
Improving the level of service to 1 temporary use ban in 50 Years
Reducing the level of service to 1 temporary use ban in 15 years
Reducing the level of service to 1 temporary use ban in 10 years92. Customers were made aware that an improvement in level of service would increase annual bills and a reduction would reduce annual bills. Due to the current economic and financial situation of many customers, the majority of customers who participated in the WTP study preferred to stay with the current levels of service across the business.
93. Fewer customers wanted an increase in performance in return for a higher bill or a deterioration in service in return for a lower bill. A reduced level of service would reduce the total supply we would have to secure for each year of the 25 year plan, and therefore reduce the number of options we would have to implement to secure supply. As customers were not willing to accept an increased risk of restrictions we did not include an option for a reduced level of service in this WRMP.
94. Customers were also asked about willingness to pay for environmental enhancements such as pollution reduction and river and bathing water quality but the enhancements included were not relevant to the development of the WRMP.
7.6.2 Customer Challenge Group
95. In developing our plans for PR14, we have worked closely with an independent Customer Challenge Group, known as the Customer Forum. The forum includes customer and local government representatives, as well as a number of our regulators. Their purpose is to ensure that we keep customers at the centre of all that we do. The Customer Forum were involved in all aspects of the WTP research. The WRMP was also presented to the group by email. Members were invited to return comments directly back to Yorkshire Water or as part of the formal consultation.
96. Our plan aims to maintain the current level of service without increasing bills above inflation. We must therefore ensure we consider this alongside customer preferences for demand reduction options and do not deviate too far from the least cost solution. 97. Our least cost solution will meet the deficit through implementing 13 demand
reduction schemes. The first six of these will deliver an additional 30Ml/d of active leakage control by 2024/25. We will not require any new infrastructure in AMP6. 98. The deficit is due to climate change reducing available supply however, population is
forecast to increase by over 800,000 during the planning period. To secure supply for our customers we will need to invest in new resources alongside demand reduction in the future. The first resource development scheme is required in year 10 of the planning period with a further two required in years 12 and 13. The largest resource development scheme is required in 2027/28, when the D20 Ouse Raw Water Transfer will be implemented. By this stage we will have reduced demand by 37Ml/d. 99. R6 South Yorkshire Groundwater Option 1 has been highlighted by the SEA to be a
potential risk to the environment. Our customers would prefer us to invest in demand reduction options and reduce our impact on the environment. This supports our decision to constrain this option out of our feasible options.
100. To ensure demand reduction schemes are used to meet the deficit in AMP6, we have selected to constrain in the two 5Ml/d active leakage control options the optimisation model selected to meet the deficit in years 4 and 5. This is consistent with our customers’ preferences, government aspirations for demand reduction and our own strategic objectives for reducing demand.
7.7 Grid Surface Water Zone preferred solution
101. In selecting our preferred solution, we have aimed to provide a solution that minimises the environmental and social risks of the least cost solution and is flexible to an uncertain future, while remaining cost efficient.
102. Our preferred solution, to meet the forecasted Grid SWZ dry year annual average deficit, has been determined using the following criteria:
Meets the supply demand deficit whilst maintaining the current level of service of 1 temporary use ban in 25 year
Is a cost efficient solution
Takes a balanced view of our customers’ preferences
Aligns with the aspirations of our Blueprint for Yorkshire
Aligns with the business plan outcomes
Minimises the environmental and social impacts as determined by the SEA. Table 7.4 below summarises the changes we have made to the feasible options following the least cost optimisation model run. We re-ran our optimisation model with the feasible options amended as described in Table 7.4.Option Brief description Comment
R6 South Yorkshire Groundwater Option 1
Install infrastructure that allows existing
underutilised licence capacity to be transferred to other areas of the Grid SWZ.
The SEA has highlighted this option as having a risk of major adverse impact to groundwater. The Environment Agency has classed this area as water stressed and there is a risk the existing licence could be reduced in future sustainability reductions. We have removed this option from the feasible options available in our optimisation model.
D1a Active leakage control 5-10Ml/d
Reduce annual leakage target by 5Ml/d through additional find and fix activity.
This scheme has been constrained into the solution in 2018/19 to ensure the AMP6 target is met through active leakage control. This meets with our customers’ preferences for further leakage reduction and our
Strategic Business Objectives to create water efficient regions.
D1b Active leakage control 10-15Ml/d
Reduce annual leakage target by 5Ml/d (in addition to D1a) through additional find and fix activity.
This scheme has been constrained into the solution in 2019/20 for the same reasons as D1a.
Table 7.4: Summary of option changes following least cost solution
103. The preferred solution from the optimisation selected four pressure management schemes to be delivered in year 11. Although this could be feasible in a normal year it may be more difficult to achieve in a cold year, when leakage can be higher than usual. To ensure all four schemes would be in place by year eleven we adjusted the implementation years of the first three pressure management options so they would be in place before year 11.
104. To ensure we can meet the additional deficit due to the demand forecast update we have brought forward D2b Pressure Management, D20 Ouse Raw Water Transfer, R12 East Yorkshire Groundwater Option 1, D2e Pressure Management and Vale of York Phase 2 by one year. This meant the R9 North Yorkshire Groundwater Option could be delayed from 2024/25 to 2031/32. This ensures no additional resource schemes are required to meet the additional deficit.
105. The schemes included in our preferred solution to the Grid SWZ dry year annual average deficit are listed in Table 7.5 and Figure 7.5 shows implementation of the preferred solution over the 25 years.
Ref. Option Build start year Yield start year Scheme yield (Ml/d)
D1a D1a Active Leakage Control in DMAs 0- 5Ml/d 2018/2019 2018/2019 5 D1b D1b Active Leakage Control in DMAs 5-10Ml/d 2019/2020 2019/2020 5
D1c D1c Active Leakage Control in DMAs
10-15Ml/d 2021/2022 2021/2022 5
D1d D1d Active Leakage Control in DMAs
15-20Ml/d 2022/2023 2022/2023 5
D2a D2a Pressure management 2.2Ml/d 2021/2022 2022/2023 2.2
D2b D2b Pressure management 1.8Ml/d 2021/2022 2022/2023 1.8
D1e D1e Active Leakage Control in DMAs
20-25Ml/d 2023/2024 2023/2024 5
D1f D1f Active Leakage Control in DMAs 25-30Ml/d 2023/2024 2023/2024 5
D1g D1g Active Leakage Control in DMAs
30-35Ml/d 2024/2025 2024/2025 5
D2c D2c Pressure management 1.6Ml/d 2023/2024 2024/2025 1.6
D2d D2d Pressure management 1.4Ml/d 2024/2025 2025/2026 1.4
D20 D20 Ouse Raw Water Transfer 2020/2021 2025/2026 40
R9 R9 North Yorkshire Groundwater 2029/2030 2031/2032 2
C1a (i) C1a (i) Business customer audits and retrofit
one off implementation 2032/2033 2032/2033 0.6
R12 R12 East Yorkshire Groundwater Option 1 2025/2026 2032/2033 6.55
D2e D2e Pressure management 1.2Ml/d 2035/2036 2034/2035 1.2
R8b R8b Vale of York Phase 2 2030/2031 2035/2036 13.4
C8 C8 Supply pipe leakage reduction 2038/2039 2039/2040 4.16
Total 109.91
106. The preferred solution provides a balance of demand reduction options and options to increase supply. The demand side options will meet our customers’ aspirations and our business objectives to take less from the environment and reduce leakage further. The additional supply side solutions will ensure water is available for supply in the future, and add further adaptability and resilience to the grid.
107. A total of 47.96Ml/d demand reduction will be achieved by delivering 14 demand side schemes over the 25 years. Our leakage target will be reducing from year four onwards through additional active leakage control, pressure management and supply pipe leakage reduction. Business customer retrofit starting in year 18 will also reduce the need for additional supply.
108. Four supply side options will be delivered providing 61.95Ml/d additional resource. The first will be in year 11 when we implement our largest resource solution, the D20 Ouse Raw Water Transfer, to provide 40Ml/d. In year 17 we will increase abstraction form an existing borehole in North Yorkshire by 2Ml/d and in year 18 we will implement the East Yorkshire Groundwater Option 1 to provide 6.55Ml/d. Our final resource solution will provide a yield of 5.36Ml/d in year 21 that will increase to 13.4Ml/d by year 23.
7.7.1 SEA of preferred solution
109. The main difference between the least cost and the preferred solution SEA (Table 7.6), results from the omission of R6 South Yorkshire Groundwater Option 1 and the R49 East Yorkshire Groundwater Option 2. R6 was constrained out of the feasible options so that it could no longer be selected. This leads the optimisation model to select a different set of options and R49 is no longer selected as part of the solution. However, R8b Vale of York Boreholes Option 2 and C8 Supply Pipe leakage reduction, which were not included in the least cost solution, are part of the preferred solution.
110. R8b Vale of York Boreholes Option 2 is the only additional resource option included in the preferred solution. This scheme has a number of minor adverse impacts. The scheme involves construction of several new borehole abstractions in the Vale of York area. Yield from the boreholes would be released to the River Ouse at low flows to be abstracted further downstream to treat at an existing treatment works. This scheme is dependent on the Environment Agency granting abstraction licences. Licences would be required to abstract from the new boreholes and for the subsequent downstream of the water we release to the river, in addition to the water we are already permitted to abstract at low flows.
111. There is uncertainty around the exact location of the boreholes and we will need to carry out investigations to show the abstractions would not have an adverse impact on the surrounding surface water. The SEA, HRA and WFD assessments have all indicated that adverse effects on the environment can be avoided by careful siting of the boreholes to ensure no adverse effect on surface waters. There would be no adverse effects on river flows as the groundwater in this area is not in hydrological connection with the river. A study by Arup consultants in 2007 concluded up to 60Ml/d was potentially available. We have planned for a yield benefit of 13.4Ml/d and have allowed a five year lead in time for the investigations to be complete. This allows for an alternative scheme to be found if 13.4Ml/d is not available.
112. Scheme C8 Supply Pipe Leakage Reduction has been added to the preferred solution in the final year of the planning period to contribute a 4.16Ml/d reduction in the overall demand for water. This scheme provides some minor beneficial impacts for the environment with only a small number of minor adverse impacts which relate to some localised temporary nuisance associated with the supply pipe renewal process, use of materials and vehicle emissions. Other impacts have been assessed as negligible.
Option Category Schem e Ref. P o p u la tio n a n d h u m a n h e a lth M a te ri a l a s s e ts a n d r e s o u rc e u s e S o il, g e o lo g y a n d la n d u s e A rc h a e o lo g y a n d c u ltu ra l h e ri ta g e L a n d s c a p e a n d v is u a l a m e n ity 1.1 1.2 2.1 3.1 4.1 4.2 4.3 4.4 5.1 6.1 6.2 7.1 8.1 Customer
conservation C1a (i) + N N + N + N ++ n/a - N n/a n/a
---Major adverse Customer conservation C8 N N - M N + N + N - + N N --Moderate adverse - Minor adverse N Negligible Leakage D2 a to D2 e + N N + N + N + N N N N N U Uncertain Internal Transfer D20 - N - - - - N N - - + N N M Mixed Groundw ater R8b M N - - M M N N N - + - M + Minor benefits Groundw ater R9 - N N N N N N N N N N N N ++ Moderate benefits Groundw ater R12 N N - N - - N N N - N N - +++ Major benefits Key
Supply Pipe Leakage Reduction
Schem e Nam e
Corresponding SEA Objective Num ber
Business customer audits and retrofit one off
SEA Topic B io d iv e rs ity , flo ra a n d f a u n a W a te r A ir a n d c lim a te N M + ++ N ++ N - + N Pressure management Ouse Raw Water Transfer
Vale of York Phase 2 North Yorkshire Groundw ater East Yorkshire Groundw ater Option 1 Leakage D1 a to D1g Active Leakage Control in
DMAs
+ N
7.7.2 SEA cumulative impact assessment
113. A cumulative assessment of the preferred programme was undertaken to consider whether the preferred solution options, when constructed or operated together, led to additional effects on each of the SEA topics.
114. The majority of leakage, pressure management and customer demand management options are mutually compatible, with implementation of each option in parallel increasing the overall volume of water savings made. There are cumulative beneficial effects arising from these options being implemented in combination. Conversely, no adverse cumulative impacts with other distribution or resource management options were identified.
115. The majority of distribution (water transfer options) and resource management options are mutually compatible, with implementation of each option in parallel increasing the overall volume of reliable water supplies. There are potential risks of cumulative adverse effects on the River Ouse with respect to scheme R12 North Yorkshire Groundwater operating in combination with scheme D20 Ouse Raw Water Transfer. However, the operational effect of the R12 groundwater scheme on flows in the River Ouse are assessed as minor given the buffering effect of groundwater storage and the scale and frequency of use of the scheme. In conclusion, the effects on SEA topics are neither enhanced nor exacerbated by these two schemes being operated cumulatively.
116. As well as the HRA and WFD assessment, we have assessed the potential effect of the schemes in the preferred plan on Sites of Special Scientific Interest (SSSIs) as part of the SEA, both individually and cumulatively. The assessment concluded that, for the majority of SSSIs, there would be a negligible effect from scheme construction or operation. There are just two SSSIs (Upper Dunsforth Carrs SSSI and Pilmoor SSSI) for which the potential for minor adverse effects have been identified in relation to the Vale of York boreholes scheme. However, any effects on these SSSIs will be avoided by careful design of the scheme such that the required new boreholes and water pipelines are not developed in proximity to these environmentally sensitive sites.
117. Further details on the SSSI assessments for each of the schemes in the preferred solution are provided in the SEA Environmental Report accompanying this document. 118. At a programme level, no significant cumulative effects have been identified between
our WRMP, and the WRMPs and drought plans of other neighbouring water companies. Equally, no significant cumulative effects have been assessed in combination with the Humber River Basin Management Plan, local development plans, or other development projects in the Yorkshire Water region (including infrastructure projects such as the proposed high speed rail link (HS2) to Leeds).
7.7.3 Mitigation and monitoring
119. Consideration of mitigation measures has been an integral part of the SEA process. The SEA appraisals have been based on residual impacts that are likely to remain after the implementation of reasonable mitigation.
120. Table 7.7 gives a timeline of the implementation of each resource option in the preferred solution. This includes a period of monitoring and assessment to show when the investigations of the environmental effects would be carried out.
121. Where appropriate, the SEA has identified additional mitigation measures that may be required, either during the construction phase or operational phase of the resource options in the preferred solution. These mitigation measures will be further defined during the more detailed design stages of the schemes as they come forward for implementation. Mitigation measures will also be discussed as appropriate with the environmental regulators, planning authorities and English Heritage within the timeframes set in the resource planning timetable shown in Figure 7.10.
122. Appropriate monitoring has been identified in the SEA to track any potential environmental effects during implementation of the options, which will in turn trigger deployment of suitable and practicable mitigation measures. Prior to implementation, we will review the specific requirements for environmental monitoring in consultation with the Environment Agency, Natural England and English Heritage.
123. We will fully comply with the requirements of The Water Supply (Water Quality) Regulations 2000 (as amended 2007 and 2010) Regulation 15, when considering introducing any new sources to be used ultimately for drinking water. Specifically, we will meet the arrangements stated in Drinking Water Inspectorate (DWI) Information Letter 06/2012, around providing adequate information to the DWI; appropriate sampling and monitoring; reporting requirements; following our Drinking Water Safety Planning risk assessment methodology; and submission of Regulation 28 documentation as necessary.
7.7.4 Habitats Regulations Assessment and Water Framework Directive Assessment
124. A HRA has been prepared to assess the potential for likely significant effects of the WRMP options on sites designated under the Habitats Directive, Birds Directive and the international Ramsar Convention. The findings have been discussed with Natural England and the Environment Agency.
125. The HRA screening assessment of the preferred solution has concluded that, with mitigation taken into account, the preferred plan is not likely to have significant effects on the integrity of any of these designated sites based on current information and designations.
126. Concerns have been raised during the consultation on our WRMP as to the potential impact of additional abstraction pressure on the dissolved oxygen concentrations in the Lower Ouse during low flow conditions in the summer months which may lead to adverse effects on designated migratory fish species and on the Humber Estuary European Marine Site (EMS). Only one scheme (Ouse Raw Water Transfer) has the potential to impact on flows in the Lower Ouse and this has been assessed as part of the HRA process.
127. The Ouse Raw Water Transfer scheme involves additional abstraction of 40 Ml/d, but this remains within the existing maximum abstraction licence conditions. The
Environment Agency has previously reviewed the impact of the abstraction at maximum licence volumes and concluded that this would not have a likely significant effect on the Humber Estuary EMS and migratory fish species.
128. The HRA has also concluded that the additional abstraction of 40Ml/d would not lead to likely significant effects on fish migration or on the Humber Estuary. This conclusion is based on previous investigations which showed that the dissolved oxygen risks occur in the summer months (June to September) which do not overlap with the key fish migration periods (October to May). Extensive water quality modelling work carried out during recent years also demonstrates that the scale of flow change arising from the additional 40Ml/d abstraction would have a negligible effect on dissolved oxygen concentrations. Environment Agency modelling has shown that dissolved oxygen concentrations are not sensitive to changes in abstraction rates of this magnitude.
129. Cumulative assessment of the WRMP with other water company WRMPs, drought plans and other relevant programmes and plans has also concluded that there would be no likely significant effect on any designated sites.
130. In line with regulatory guidance, we have carried out a Water Framework Directive (WFD) assessment of the preferred solution to ensure that none of the schemes, either in isolation or in-combination, would lead to a deterioration in waterbody status. 131. Each scheme has been evaluated to assess the impact on surface water and/or
groundwater bodies designated under the WFD. The assessed impact of abstraction on groundwater levels and river flows from each scheme has been used to examine the potential effect on ecological, water quality and water resource parameters and status classification for each WFD waterbody.
132. The WFD assessment report has been shared with the Environment Agency and has concluded that:
None of the preferred solution schemes operating in isolation or cumulatively would lead to deterioration of waterbody status. Therefore the WRMP is compliant with the WFD requirements set out by the in the Waterresources planning guideline (Environment Agency et al., 2013).
None of the schemes lead to any impediments to the attainment of Good WFD Status (or potential) or compromise the attainment of WFD objectives. In addition, none of the schemes have adverse effects on other water bodies. The assessment therefore confirms that the WRMP is compliant with the WFD objectives.Option Ref. Option Name
2020/21 2021/22 2022/23 2023/24 2024/25 2025/26
Habitats Regulations Assessment
Install pipeline, fish screens and water
treatment work upgrades
Full yield available
2025/26 2026/27 2027/28 2028/29 2029/30 2030/31 2031/32 2032/33
Review groundwater level
and chloride monitoring data
Full yield available
2029/30 2023/24 2031/32
Test pumping and HIA (hydrogeological impact assessment) Continue monitoring. Complete infrastructure (pumping and chlorination) and
apply for licence
Full yield available
2030/31 2031/32 2032/33 2033/34 2034/35 2035/36 2036/37 2037/38
Full yield available
R9 North Yorkshire Groundwater
D20 Ouse Raw Water Transfer
R12 East Ground Water option 1
R8b Vale of York Boreholes Phase 2 HIA and pump testing
WFD assessment of potential abstractions
Continue testing and WFD assessment.
Install infrastructure (pipelines etc) and apply for abstraction licences Partial yield available 2035/36 and 2036/37
Time line for implementation
Environmental Impact Assessment and engineering scoping
Investigate impact of pressure changes and new infrastructure Install infrastructure (pumping capacity and network modifications)
7.7.5 Customer preferences to preferred solution
133. Our customer survey highlighted our customers considered demand reduction options to be their preferred solutions.
134. Our customer preferences are taken into account in our baseline scenario through our commitment to delivering water efficiency and metering. We will continue to drive water efficiency through the activity discussed in Part 3, Section 5. Our AMP6 metering strategy aims to increase the number of meter optants to an average of 40,000 per year.
135. This ensures we can reduce demand regardless of whether or not a deficit is forecast in a water resource zone. We feel this is more in keeping with customer preferences and government aspirations than determining our metering and water efficiency strategy through the options appraisal process. However, we do include feasible options for further metering and water efficiency schemes.
136. The least cost solution provided 44.10Ml/d of demand reduction, through additional active leakage control, pressure management and business customer water efficiency. Our preferred solution provides a slightly larger volume of demand reduction at 47.96Ml/d.
137. The preferred solution includes each of the demand reduction options that were selected in the least cost solution but implements them in a different order. In addition to this the preferred solution includes supply pipe leakage which means our preferred solution provides more demand reduction than the least cost solution. Both solutions selected the active leakage control options at the beginning of the planning period as these are the most economical options.
138. Demand reduction schemes meet 44% of the total deficit. The majority of this is delivered in the first ten years of the planning period with no resource options being required.
139. Demand reduction is partially dependent on developments in leakage reduction techniques. We believe that in future WRMPs, we will be able to reduce leakage further, which will reduce the number of supply side options we are proposing in this plan.
140. Although our customer preferences are to meet deficits through demand reduction, as the deficit increases, we will need to invest in new resources to secure future supplies economically. Going forward the remaining 56% of the deficit is met through new supply side options. However, our preferred solution delivers sufficient demand reduction schemes to ensure our weighted average demand is met without the need for new resources.
141. The weighted average demand is the demand that we are most likely to face over the planning period (see Section 4.6). Our preferred solution aims to meet the dry year annual average scenario. This means we will only require the additional resource options in particularly dry years and in the majority of years our demand reduction schemes will close any deficit.
142. Two of the four supply side schemes will utilise existing licences, providing additional supply and increasing the ability to move water around the Grid SWZ. This will allow additional internal transfers that will enhance the resilience of the grid system.
143. The Ouse Raw Water Transfer provides a yield of 40Ml/d, which is the majority of the supply side yield. This scheme utilises an existing Yorkshire Water licence that is classed as sustainable under the Environment Agency CAMS. Investment is required for installation of a pipeline to deliver the water to an existing treatment works with spare capacity. This means we can obtain an environmentally sustainable, high yield at a relatively low cost.
144. We consider this option to be a good solution to an uncertain deficit as it secures our level of service for the forecast supply demand balance and is cost effective. Environmental investigations and monitoring will ensure the impact on the environment is minimalised.
7.7.6 Final planning headroom assessment
145. To ensure we can be confident our preferred solution will meet the forecast deficit we must consider the risks of the selected options in headroom for the Grid SWZ final planning scenario assessment.
146. The Grid SWZ probabilistic model used to calculate target headroom for the baseline scenario was updated with the uncertainties associated with the preferred solution options. The model was then run to provide a target headroom profile for the final planning scenario.
147. Our headroom policy is that target headroom is the greater of the headroom profile and 5% of the baseline WAFU. The final planning target headroom profile was found to be less than 5% of baseline WAFU. Therefore no further adjustments to the solution were required.
7.8 Grid Surface Water Zone preferred solution sensitivity testing
148. Our Grid SWZ dry year annual average baseline scenario predicts a deficit of 2.67Ml/d in 2018/19 increasing to 108.65Ml/d in 2039/40. Our final planning scenario for the Grid SWZ aims to implement appropriate schemes to close the deficit and secure supply.
149. We forecast the deficit by estimating the supply demand balance components of the zone for the next 25 years. Although we have based the components on the best available information there are many uncertainties within our forecasts.
150. To understand the risk of uncertainty in the Grid SWZ baseline scenario, we have considered four further scenarios. These scenarios have been used to assess the flexibility of our preferred solution to a deficit greater or less than forecast. A summary of the scenarios is provided in Table 7.8.