River quality has improved greatly since 1990.
Water quality has improved over the last two decades and, by working with the water industry and others, we have dealt with many of the major sources of pollution. We are now changing the way we measure the quality of the water environment to help us focus on other sources of pollution so we can continue to protect and enhance public health as well as the health of water plants, animals and habitats.
How do we measure river quality? » How good is our water quality? » How does this compare with classification results for the WFD? » What are we doing to improve water quality? » Find out more
How do we measure water quality?
The way we measure water quality is changing. For twenty years, we have been using a general quality assessment (GQA) scheme to assess river water quality in terms of chemistry, biology and nutrients. GQA has helped drive environmental improvements by dealing with many of the major point sources of pollutants, such as discharges from sewage treatment works or other industry. We now need a more sophisticated way of assessing the whole water environment that will help us direct action to where it is most needed.
The European Water Framework Directive (WFD) will give us the means to do this by looking at over 30 measures, grouped into ecological status (this includes biology as well as ‘elements’ like phosphorus and pH) and chemical status (‘priority substances’). The WFD covers estuaries, coastal waters, groundwater and lakes as well as rivers.
How good is our water quality?
River water quality has generally improved over the past couple of decades in terms of chemistry and biology (Indicator: Rivers of good or excellent quality). We’ve also seen a fall in the amount of nutrients in our rivers over this time (Indicator: rivers with high levels of nutrients). Water quality is assessed slightly differently in England and Wales so we’ve reported the results separately here.
Biological quality - an indicator of overall ‘health’ of rivers
We want to see as many rivers as possible in the top two quality bands of excellent or good. In 2007, 72% of English rivers were at this level – the best on record, compared with 55% in 1990. 87% of Welsh rivers were of good or excellent quality, compared with 79% in 1990.
Chemical quality - an indicator of organic pollution in general
Again, we want to see as many rivers as possible of excellent or good quality. In 2007 76% of English rivers were at this level compared with 55% in 1990. 95% of Welsh rivers were of good or better quality – the best on record, compared with 86% in 1990.
Nutrient status - phosphate and nitrate in rivers
For nutrients we want to see as few rivers as possible with high concentrations of nutrients, that is greater than 0.1mg/l for phosphate and 30mg/l for nitrate. In 2007, 54% of English rivers had high concentrations of phosphate compared with 69% in 1990 and 10% of Welsh rivers had high concentrations of phosphate, compared 26% in 1990. We found high concentrations of nitrate in 32% of English rivers compared with 36% in 1995. High concentrations of nitrate rarely occur in Welsh rivers.
How does this compare with classification results for the WFD?
WFD monitoring is risk-based, focussed where there is likely to be a problem, and classification is based on a far wider range of assessments than GQA. WFD uses a principle of ‘one out, all out’ which means that the poorest individual result drives the overall classification. These differences to the way we measure water quality mean that WFD results will appear poorer than GQA results. It is the same improving water environment, just a more sophisticated way of measuring it.
Draft results for assessed rivers in England and Wales show that for overall ecological classification 23% of rivers are good or better, 60% are moderate, 12% are poor and 4% are bad. These figures include the ecological potential where water bodies are artificial or heavily modified. Some water bodies will never achieve good ecological status because they have been physically altered for a specific use, such as navigation, recreation, water storage or flood protection. Ecological potential is based on the quality that can be achieved given a water body’s changed conditions.
Results for all assessed surface water bodies show that 23% meet good ecological status or better, which includes 30% of lakes and 30% of estuaries and coastal waters (Figure 1: status of all water bodies). Three-quarters of surface water bodies are classed as good where assessed for chemical status.
Results for assessed groundwaters show that 65% meet good quantitative status (in relation to groundwater abstraction pressures) and 59% meet good status for chemicals.
What are we doing to improve water quality?
WFD will give us a better understanding of the whole water environment. This will help us direct action where it is most needed. The default aim of the WFD is that water bodies reach ‘good’ status or better. It is designed to deliver improvement over three six-year cycles to 2027. We will use the consultation of the draft River Basin Plans to maximise the length of river that will improve to good status by 2015.
We will work with our partners, stakeholders and those with an interest in our water environment to decide a programme of environmental enhancements and we’ll make the necessary improvements that are set out in our final River Basin Plans. So for some water bodies we aim to meet good status by 2021. For other water bodies 2027 will be the target date.
*Classifications will be finalised by December 2009.
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