Diffuse pollution is one of the biggest challenges to improving water quality in England and Wales. Diffuse pollution occurs when small amounts of pollutants – often from many different sources – are washed into a water catchment across a wide area. On their own, the sources of this pollution can be relatively minor. But taken together, they can affect significantly the quality of the untreated water in individual catchments – and damage the wildlife and plants they support. Because the sources of pollution tend to be spread out, they can be hard to spot. This can make it more difficult to stop pollutants entering catchments and prevent them from damaging the water environment.
In the past, to deliver the good quality drinking water we all enjoy, the companies and their customers have paid for intensive treatment processes once water has been taken from the environment. After we have used this water, it must be treated to remove pollutants before it is returned to the environment. Again, customers pay for this.
Continuing to use such approaches would be very costly. They could also damage the environment. Another concern is that current treatment approaches do not remove pollutants from the surrounding environment – only from water that is for public use. This means that pollution could remain in the environment where it would continue to affect the wildlife that our rivers and streams sustain.
Upstream catchment management schemes could be a more sustainable way of helping to ensure good quality drinking water. This is because they tackle diffuse pollution at source before it reaches a water treatment works. They may also help the companies to find more cost-effective ways of meeting their environmental obligations.
Companies are using a variety of approaches to prevent or reduce the amount of diffuse or other pollution entering water catchments. Early results from several of the companies suggest that some of their catchment management schemes are beginning to deliver benefits for customers. But across England and Wales there is not yet enough evidence overall to show that catchment management schemes deliver better water quality and lower treatment costs – that is, benefits that will hold down the bills that customers would otherwise have to pay.
There is still a lot of work for the companies and other stakeholders to do before 2014, when decisions need to be taken on which new schemes customers will fund – and which existing schemes they will continue to pay for. They need to build the evidence base to show the effectiveness and benefits of particular techniques.
Our ‘From catchment to customer – can upstream catchment management deliver a better deal for water customers and the environment?’ focus report describes some of the catchment management approaches companies are trialling to prevent or reduce diffuse pollution and the issues that need addressing in order for customers to benefit from them.
- ‘Tackling diffuse water pollution in England’, National Audit Office, July 2010.
- ‘Managing Water, Managing Land’, Wessex Water, April 2011.
- ‘The natural choice: securing the value of nature’, UK Government White Paper, Defra, June 2011.
- ‘Strategic Policy Position Statement on Water’, Welsh Government, 2011.
- United Utilities has a section on its website devoted to its SCaMP project at www.unitedutilities.com/scamp.aspx
- More information on the Water Framework Directive is available at www.euwfd.com/html/what_is_the_wfd-.html
- The Environment Agency’s maintains a list of catchments
- Statistics on water supply use are available on the Defra website at archive.defra.gov.uk/evidence/statistics/environment/inlwater/iwsupplyuse.htm