Climate change mitigation – contrasted to the tunnel's significant carbon footprint, Enjoyment, aesthetics and health benefits of green spaces and nature, Reduced urban heat island effects with an associated reduction in cooling load and carbon emissions, Improved urban biodiversity. Earlier avoidance of EU fines for not meeting water standards than under the scheme. Continued overflows forecast The annual number of CSO discharges is set to fall from average of 60 a year to under five. The Environment Agency is satisfied predicted Tideway water quality after such discharges will be acceptable. When both the tunnels are operational, the overflows occur after sustained periods of intense rainfall and after the tunnels have captured the most damaging ‘first flush’ from the foul sewers. The remaining total overflow is an average of 2.6 million cubic metres per year, on 2011 estimates. References External links London water infrastructure Proposed infrastructure in London Proposed tunnels in the United Kingdom Thames Water Tunnelling organizations 2024 in the United Kingdom 2020s in London 2020s architecture Nationally Significant Infrastructure Projects (United Kingdom)