Getting in a lather over SuDS

 We face the extreme dichotomy of too little water versus too much water, yet we fail to harness and make the most efficient use of the water resource – and thereby ‘miss a trick’ integrating our land and water management to yield multiple benefits.

  • Water covers 70 per cent of our blue planet, but only 2.5 per cent of that is freshwater, and scarce a drop of that is available to drink.
  • In China, two thirds of groundwater and one third of surface water was rated as ‘unfit for human contact’ in 2014. Note that I write ‘contact’ not ‘consumption’.
  • By 2030, it is predicted, demand will have exceeded supply by 40 per cent and half of us, globally, will live in ‘water stressed areas’.
  • The Water Cycle is being accelerated by climate change, with resultant sea level rise, inundation and soil salinisation. 

I continue to work myself into a lather every time I flush a traditional toilet in the UK and 13 litres of potable water is discharged from the cistern.

The UK Government’s Climate Change Risk Assessment presents compelling evidence that the increases in heavy rainfall will significantly increase the risks from fluvial and surface water flooding by 2050. The pressures for development, however, are unabated. The UK Government has a target to build one million new homes by 2020.

The benefits of Sustainable Drainage Systems (SuDS) are well known. SuDS reduce flood risk by slowing and storing the water using natural processes. Properly done, SuDS is the manifestation of multiple land use and sound integrated land and water management, the natural features in our urban spaces yielding improved mental well-being, promoting physical activity and creating attractive amenity locations. These areas clean the air we breathe, absorb carbon dioxide and help water infiltrate into the ground rather than overloading drainage networks causing surface flooding.

CIWEM, in partnership with the Wildfowl and Wetlands Trust and Exeter University, has conducted the Big SuDS Survey, the largest of its kind in the UK – and the Report’s conclusions are quite stark. We need:

  • More rigorous policy, with SuDS required as an integral part of initial development proposals
  • New standards – repeal automatic right to connect to conventional systems
  • Resolution of adoption – all assets need to be properly maintained
  • Reflection on the cumulative effects of minor and permitted developments
  • To review the retrofit measures.

The Government’s review of the planning rules needs to address these representations, otherwise there will be further years of lost opportunity. Learning from the devolved administrations would be a start – Scotland, Wales and Northern Ireland already have more sophisticated arrangements in place.

There are also lessons to be learnt from overseas. Interestingly, two years ago CIWEM accredited a course at Chongqing University as a route to professional qualification. We now have 294 student members there – the new generation who deserve a better inheritance and will surely leave a more sustainable legacy.

Chongqing, China Photo: iStock/SeanPavonePhoto
Chongqing, China
Photo: iStock/SeanPavonePhoto

China’s ‘sponge city’

China is responding to the challenge of half of its 657 cities, housing 680 million people, being classified as being ‘water scarce’, whilst the other 50 per cent fail a national standard for flood prevention. Chongqing, a city of 10 million, is one of 16 urban districts where the concept of a ‘sponge city’ is being piloted. Permeable roads, filtration ponds and wetlands, public spaces and rooftop gardens are integral parts of the infrastructure to harvest rainwater and use it recharge depleted aquifers, irrigate urban farms and use greywater to flush the toilet and wash the car.