The London Assembly Environment Committee is calling for an acceleration of investment by Thames Water into its wider sewer infrastructure to ensure that it has the capacity to deal with intense rainfall events.
The call comes after the Committee heard evidence that 40 million tonnes of raw, untreated sewage are currently discharged into the Thames every year during storm events.
The Committee’s report – ‘Water and London’s Rivers’ – includes 21 recommendations to the Mayor, Thames Water and Government, covering four main areas, drinking water and water scarcity, wastewater and pollution, flooding, and maximising opportunities to create a sustainable water system.
For tidal flooding, the Committee says it is imperative to replace the Thames Barrier – and to ensure appropriate sites are properly safeguarded for this.
The primary defence mechanism to deal with tidal flooding in London, the Thames Barrier became operational in 1982 and consists of ten steel gates which are closed in storm surge conditions. It currently protects over 1.4 million people and 586,000 residential properties worth over £321 billion,as well as 55,640 commercial properties, 4,000 listed buildings and 27 square kilometres of open green space from flooding.
London’s sewerage system was originally developed in the 19th century to deal with a population of around 2 million people.The system is now significantly strained - the population of London today just under 9 million and is expected to grow to over 10 million by 2040.
Insufficient capacity in the sewage pipes to contain all the rainwater and sewage, and to prevent it from ‘backing up’ into people homes, means it is released through storm overflows.
The report sets out the following 16 key recommendations:
Drinking water and water scarcity
Recommendation 1- Thames Water and Ofwat should set a more ambitious leakage reduction target in future, aiming for zero leakage by 2050, and be more proactive in monitoring and addressing leaks.
Recommendation 2 - Thames Water and the Mayor should work together on information campaigns to promote reductions in water usage across London in 2024 and beyond.
Recommendation 3 - Thames Water should also continue to expand smart metering to inform people of their water use, particularly targeting those that use the most water.
Recommendation 4 - Thames Water should coordinate with Ofwat to open a consultation on new water tariff options for the 2025-2030 price control period. This should include options to link the charging structure to water use, as well as social tariffs to ensure water remains affordable to all.
Recommendation 5 - Thames Water should work proactively with local communities to adequately respond to their concerns around new infrastructure to secure future water resources and should learn lessons on effective community engagement for future consultations.
Recommendation 6 - Given the environmental impacts of the proposed Direct River Abstraction scheme at Teddington on water temperatures and a Site of Importance for Nature Conservation, the Mayor should encourage Thames Water to explore alternatives.
Wastewater and pollution
Recommendation 7 - Thames Water should accelerate investment in its wider sewer infrastructure in areas of London not covered by the Thames Tideway tunnel, to ensure that it has the capacity to deal with intense rainfall events. The Committee considers that the distribution of costs to cover necessary infrastructure must not adversely impact the affordability of water for customers.
Recommendation 8 - All overflow points should have Event Duration Monitors fitted and real-time data about outflows should be published on the website, along with three monthly summaries, as is already the case where Monitors are installed.
Recommendation 9 - The Mayor should encourage his environmental team to prioritise work to bring together groups and engage communities on the health of their local rivers in 2024-25. This should include supporting ‘Outfall Safaris’ and providing guidance to communities in London about how to work with government, local authorities, charities, water companies and the Environment Agency to help reduce pollution.
Recommendation 10 - The Government should further increase funding to the Environment Agency for enforcement activity, in order to enable the Agency to effectively monitor river health and enforce environmental protections in London.
Flooding
Recommendation 11 - The Mayor should continue to support the London Surface Water Strategic Group to encourage a joined-up approach across London.
Recommendation 12- The Mayor should significantly scale up funding and installation of sustainable drainage systems (SuDS), and scale up the resources available for local boroughs and other landowners to increase their own SuDS installation.
Recommendation 13 - The Mayor should double the target in his Transport Strategy to 100,000 square meters a year of roads draining into sustainable drainage systems (SuDS) per year. Transport for London (TfL) should also double its targets for SuDS installation to deliver 10,000 square metres of roads draining into SuDS per year.
Recommendation 14 - Defra should work with the London Surface Water Strategic Group to establish a need-based fund to enable boroughs to access simple and long-term funding for sustainable drainage systems (SuDS), while significantly increasing funding available for SuDS installation.
Recommendation 15 - As recommended by the London Climate Resilience Review, the Mayor should conduct an audit of land the GLA owns or is responsible for on the riverbank and develop an action plan by 2025, including ways to raise flood defences and create natural areas where flooding can be allowed to occur without harm.
Recommendation 16 - The Mayor should also consider how to use his wider planning powers to ensure councils develop riverside strategies and landowners take appropriate action to construct and manage higher walls.
The report comes after a two-part investigation by the Environment Committee, with the Committee firstly speaking with Thames Water, River Action, South East Rivers Trust, Thames21 and the Greater London Authority (GLA). The Committee then heard from Thames Water, the Environment Agency, the PLA, the GLA, Zoological Society London (ZSL) and Tideway in the second Committee meeting.
The Committee also carried out two site visits as part of the investigation, visiting the Thames Barrier with the Environment Agency and the Port of London Authority (PLA), and also visiting Mogden sewage treatment works in west London with Thames Water.
Léonie Cooper AM, Chair of the London Assembly Environment Committee, said:
“The London Assembly Environment Committee investigation looked at London’s water and rivers to explore the impacts of climate change, flood risk, sewage pollution, the potential to reduce emissions and how to ensure sufficient water for London in the future.
“In recent years, as a result of climate change and rising sea levels, we are seeing more instances of surface water flooding in London, and it is clear that further investment is needed in this area.
“Our investigation gave the Committee a fascinating insight into the challenges and opportunities for Thames Water, the Environment Agency and the Mayor when it comes to protecting our water and rivers.
“We heard how the current level of water usage in London is unsustainable, and places significant strain on London’s water supply.
“Change is urgently required to protect London’s water supply for future generations, and there must be a joined up approach, with so many stakeholders involved in managing and protecting our water and rivers.
“I urge the Mayor, Thames Water and Government to take forward our recommendations and create a sustainable water system for future generations.”
The Committee is also calling for the Mayor and the Port of London Authority (PLA) to work together to create a prospectus for investors of river-based energy projects, and actively market the opportunities identified to ensure more renewable energy generation projects on the Thames are installed.
The Thames and other tributaries were collectively identified by government in 2015 to have the “highest potential for water-source heat pump deployment in areas of high heat demand” across England. In 2020, a trial estimated that tidal energy in the Thames could power 35,000 homes from hundreds of turbines.
Click here to download the full report