Issue - meetings

Presentation from Southern Water on their work to reduce the use of Storm Overflows (Combined Sewer Overflows).

Presentation from Southern Water

21.1     Dr Nick Mills, Head of Clean Rivers and Seas Taskforce and Chris Braham, Head of Wastewater Asset Strategy and Planning, from Southern Water gave a presentation to update the Committee on the work taking place on storm overflows in East Sussex and the responses to a number of written questions submitted to Southern Water by the Committee in advance of the meeting.

Responses to Written Questions

21.2     The Committee were presented with responses to the following written questions, with additional information provided by Dr Nick Mills and Chris Braham.

1) What plans are there in East Sussex to reduce surface water entering your Combined Sewers during heavy rainfall?

Dr Nick Mills outlined that Southern Water had published a Storm Water Investment Plan on its web site and would welcome any feedback on the investment proposals. The Investment Plan was submitted to the regulator, Ofwat, in October for approval and work will continue on sharing the plans for investment with stakeholders. The focus of these plans is managing water that should not be in the sewer system such as run-off from roads and domestic properties. Southern Water will work closely with East Sussex County Council (ESCC) on this work and is testing a number of approaches through a series of Pathfinder Projects including the one at Fairlight in East Sussex.

There is over £220 million pounds of investment contained in the next Asset Management Plan investment period (AMP8 2025 – 2030) targeted at developing sustainable drainage systems to deal with grey water run-off. The approach is to take water out of the sewer system first before increasing the ‘end of the line’ capacity at water treatment facilities. This will include work on permeable solutions such as sustainable urban drainage systems (SUDs) and slowing the flow of water into the system by using smart water butts. During AMP 8, Southern Water hope to reduce releases from 21 outfalls, 17 of these are activating primarily due to excess surface water entering the combined sewer.

2) Are 100% of your storm overflow discharges now monitored as the committee understands that is the Government’s new target?

Southern Water is very close to monitoring 100% of overflows, and all overflows will be monitored by the end of 2023.

3) After the public outcry over the 3million litres of untreated water spillage in August 2022 at Galley Hill pumping station there were plans to provide signage to stop misinformation being circulated. Along Bexhill Seafront signs for the thirteen outfall pipes were designed, and agreement was reached with Rother District Council on positioning them. Please could you inform us when these will be erected?

Southern Water has decided not to continue with the signs for the outfall pipes as it may lead to confusion about what the outfalls are for, and will need to re-think the best way of providing this information. This could be through other awareness and education activities.

4) A sewer pipe at Bulverhythe in St. Leonards on Sea  ...  view the full minutes text for item 21

Presentation by Southern Water on the actions it is taking to reduce the use of storm overflows and sewage discharges.

22.1     Dr Toby Willison, Director of Quality and Environment, Southern Water introduced the presentation on Southern Water’s work to tackle the issue of storm overflows and sewage discharges. He outlined that Southern Water places a high priority on its impact on rivers, water courses and the sea. It has accelerated investment to tackle these issues, and this has included nature-based solutions and better water quality monitoring.

22.2     Toby Willison outlined that at the time of privatisation of the water industry, around 70% of sewage discharges went directly into the sea without treatment. There has been a huge improvement in treatment since then, with 95% of sewage coming into treatment works which is fully treated. However, it is important to recognise that residents’ expectations of water quality and the quality of the environment have increased. Tackling the last 5% is the most challenging in terms of combined sewer overflows (CSOs) and spills into the environment. Southern Water as an organisation is absolutely committed to tackling this last 5%.

22.3     Dr Nick Mills, Head of Storm Overflow Task Force, Southern Water explained that the Task Force was set up twelve months ago to demonstrate the principles of how the use of storm overflows could be reduced through six pathfinder schemes. At present Southern Water is building a regional plan to meet (and exceed) the targets set in the Environment Act to reduce the use of storm overflows through a £2 billion investment programme. He outlined that there needs to be more transparency in the way the system and Southern Water operates.

22.4     It is important to separate surface water which is seen as being clean (i.e. it does not need treating) from foul sewage (e.g. from toilets). There are three approaches being taken to reduce storm overflows, which are:

• Source control. These are measures to prevent rainwater and ground water entering the combined sewer system.
• Optimisation of existing infrastructure and using more technology and monitoring.
• Building bigger infrastructure. This is expensive but it will need to be done in certain places.

22.5     In a typical water catchment area the majority of water entering the system in a storm event is surface water run-off and rainwater from rooves and roads. The base flow (i.e. the normal foul sewage flow that requires treatment) is usually quite low. The use of smart water butts and swales or Sustainable Urban Drainage Systems (SUDs) in modern housing developments can help reduce water flows in combined sewers and thereby reduce the need to use CSOs. These are the sort of areas where Southern Water would like to collaborate with other partners and be an investor, if necessary. However, it does not own these assets. At present there are pilot schemes with Kent County Council and in Fairlight near Hastings to trial some of these approaches (e.g. smart water butts).

Questions and Answers based on the presentation.

22.6     The Committee discussed the written responses provided by Southern Water to the questions the Committee had asked prior to the meeting.  ...  view the full minutes text for item 22