Water Resources Management Plan

How we forecast supply and demand

We have undertaken a detailed technical programme to develop our supply-demand balance, which forecasts whether we would have enough water to meet demand in each year from 2025 to 2080.

New planning requirements mean we must understand whether we would have enough water if a very severe “1 in 500-year drought” were to happen in each year of the planning horizon. Our calculations of water availability also account for future abstraction licence changes that may be needed to help protect the environment, in particular in local chalk catchments, as well as accounting for the impact of climate change.

Our demand forecast accounts for peak demands that would occur in a dry and hot “1 in 500-year drought”, as well as future potential changes in household and non-household demand, as impacted by population and property growth, economic growth, and changes in customer water use behaviour.

Under our central planning scenario, with no interventions (investments), we forecast a small surplus in supplies over demands in the short term to 2035, declining into a deficit over the long term due to gradually increasing demand associated with population growth, a small reduction in available water due to climate change, but also because of step reductions in the amount of water we can abstract from the environment, primarily in 2035.

How we plan to meet this need

We have explored a long list of options to both increase available supplies and reduce demand, while also assessing these options against a range of criteria, including technical and environmental feasibility, cost and environmental performance (including biodiversity and natural capital). We have also assessed the options against government expectations for reducing per capita consumption to 110 litres per person per day, halving leakage by 2050, and reducing demand by 20% per person by 2038.

We have undertaken investment modelling to identify the right mix of these options - called our preferred plan - to solve the water supply shortfall between 2035 and 2080. Consistent with our outcomes-led approach to business planning, we have assessed our plan in terms of delivery in the key outcomes of drought resilience, cost, carbon emissions and environmental performance.

As the future is uncertain, our plan is also adaptive, where alongside making investments, we will also undertake investigation work to reduce planning uncertainties to make sure we can make the best decisions in future plans.

A key part of our plan is that we commit to protecting chalk streams, including the Hampshire Avon, by substantially reducing further our abstraction licences, resulting in a 80Ml/d loss in supply during drought conditions by 2035. To achieve this, our plan includes:

• Roll out of smart meters to 95% of properties in our region by 2035, including household customers and businesses. This programme will initially target demand reductions in areas that reduce abstraction from the Hampshire Avon catchment, which will provide the greatest environmental benefits. Existing measured customers will have their basic meters upgraded; unmeasured customers will have a smart meter installed with engagement to encourage making a switch to metered bills. The data provided by smart meters will help us find leaks and reduce water consumption, so we can protect the environment and save customers money on their bills.
• Enhance our household and business water efficiency programmes, underpinned by data and insight from the smart meter roll out, to engage with over 12,000 households from 2025-2030.
• Continue to reduce leakage from 2025 to meet the regulatory target of 50% reduction by 2050. This will be achieved through utilising technology to find leaks faster by expanding our network of acoustic loggers and preventing leaks occurring through managing pressure in our network and replacing mains. Smart meters will also help us find leaks on customers supply pipes.
• Develop in 2025 a stream support option for two upper stour headwater catchments.
• By 2025, take forward several supply side schemes through design and development to be ready for potential delivery to meet licence reductions in 2035, depending on the outcome of future need and the needs of other users in the Hampshire Avon catchment.
• Given the scale of deficit in the long term, continue to investigate new regional strategic resource options, such as effluent re-use and/or a new reservoir in the Mendips, with South West Water as our main partner on the West Country Resources Group.

In combination the options included in our preferred plan will ensure we meet statutory targets to reduce demand per person by 20% by 2038, and also the associated per person consumption, leakage and non-household demand reduction targets by 2050.