Sustainable drainage schemes

A more sustainable way of managing surface water run-off to prevent sewer flooding and to improve water quality in rivers is to create sustainable urban drainage systems (SuDs). This also helps reduce our energy use as surface water is not unnecessarily treated as wastewater. They can also create greener and more diverse surroundings in urban areas.

Urban creep, loss of green space and climate change all put pressure on the sewerage network. Urban creep also puts pressure on the environment, as pollutants from transport and industry are washed off of impermeable surfaces and into rivers. Population growth adds to these challenges but the new development needed to accommodate it creates opportunities for improvements, provided the drainage is correctly designed.

Ponds are among the landscape features which can reduce or delay rainwater run-off into sewers.

We recognise that we need to manage the quantity and quality of surface water entering our sewers, as well as building more capacity where it is needed. We have therefore been working to develop alternative approaches to surface water, using green infrastructure such as rain gardens, permeable paving and water butts to either return rainwater to the ground, or to slow it down and clean it before it enters our sewers.

We work closely with local communities, councillors and MPs on numerous important issues, including development planning, flood risk management and environmental restoration.

Working in partnership with the London borough of Southwark, we delivered an award-winning scheme to alleviate the risk of flooding in Herne Hill, Dulwich, by attenuating surface runoff using SuDS.

In 2014/15 we developed innovative software to map potential opportunities to retrofit SuDS across our region. We are working closely with the Greater London Authority, the Environment Agency and the London boroughs both to explore SuDS opportunities and to manage the drainage impact of the major development that is happening across the capital.

We are also working with river restoration partnerships to improve the quality and biodiversity of our rivers and wetlands. SuDS will form a key part of this work, both to clean up polluting urban run-off before it enters the rivers and to create habitats for plants and wildlife.

We clear around 55,000 blockages from our sewers each year at a cost of £12m and over 7,000 customers suffer from sewer flooding in their homes and gardens – a truly miserable experience.

Combating sewer flooding