SOME of the country’s most important rivers need more protection from damaging pollution, new data from the Environment Agency reveals.
Many SSSI rivers have been affected by diffuse pollution: phosphate and nitrates enter rivers from land-based activities such as agriculture and via discharges from sewage treatment works, causing problems for fisheries and other river life. High phosphate levels were found in more than half of rivers in
Last year, the Environment Agency surveyed 7,000 sites, representing 40,000km of rivers and canals, for their chemical and biological water quality.
Overall, the rapid improvement in the chemical and biological quality1 of rivers witnessed during the 1990s is beginning to stabilise. The improvements followed an Environment Agency driven environment programme for rivers which has led to £5 billion being invested by water companies to improve discharges to rivers by upgrading key sewage treatment works and sewerage systems. The Environment Agency’s tighter enforcement of discharge consents along with the work with industry on pollution prevention and control is another vital component in reversing local river pollution hot-spots. There are still too many pollution incidents – in 2002 there were a total of 1,468 serious (category 1 and 2) pollution incidents to water, 21 per cent less than in 2001 but still more than in 2000.
Sir John Harman, Chairman of the Environment Agency, said: “With the measures we have taken to date, we are starting to meet our threshold of improvement in river quality. The question is whether we choose to pat each other on the back and say “Well done”? Or do we decide to raise the bar by tackling phosphates and nitrates head on, and put an end to historic pollution hot spots such as storm sewage overflows.
“With new European legislation on the horizon – the Water Framework Directive in particular – the basis on which achievement is assessed will change, so we simply can’t afford to be complacent. The healthier and more attractive the environment, the more we will see knock-on benefits for leisure, recreation, tourism and the wider economy”
For example, in North Yorkshire the River Derwent, a protected SSSI river, is home to a whole host of valuable species, including the lamprey, one of only two surviving remnants of one of the most primitive invertebrates the Agnatha or ‘jawless fish’. Investigations by the Environment Agency have highlighted the need to reduce the levels of the nutrient phosphate entering the river. The Agency is seeking action to remove phosphates from effluents at a number of sewage treatment works in the area before it is discharged into the Derwent and its tributaries. Elsewhere, the River Eden in
The new data, published today, supports the environmental priorities for water companies set out by the Environment Agency, English Nature and Countryside Council for
The Environment Agency is calling for action on:
our most important wildlife sites so that they are protected from pollution and over-use of water
stopping pollution from storm sewerage overflows (which discharge untreated sewage into rivers during wet periods)
tackling the nutrient phosphate which can upset the ecological balance of lakes and rivers, and
excessive water leakage
Work on diffuse pollution from land-based activities and agriculture is already underway. The Government has extended the area of land designated as ‘nitrate vulnerable’ in order to address high nitrate concentrations in certain rivers. The Environment Agency is actively promoting ‘best farming practices’ – simple measures to reduce the amount of nitrate that reaches rivers – to farmers across England and Wales. For example, in numerous catchments in
The results of the Environment Agency’s latest assessment of the quality of rivers and canals in
Notes to Editors
The Environment Agency has statutory duties to reduce pollution, manage water resources and conserve the environment. The Agency monitors the quality of over 40,000km of rivers and canals and 2,800km of estuaries in
River quality is one of the government’s 15 headline indicators for quality of life, and is central to the monitoring and reporting of progress towards sustainable development. They cover the three pillars of sustainable development, namely social progress, economic growth and environmental protection, including health, jobs, crime, air quality, traffic, housing, educational achievement, wildlife and economic prosperity. For further information see: www.sustainable-development.gov.uk/indicators/index.htm
The periodic review is the process that shapes water company’s business plans and water customers bills. The Environment Agency, English Nature and the Countryside Council for
1GQA data collection
The Agency uses a General Quality Assessment (GQA) scheme to classify water quality in rivers and canals. The scheme provides a way of comparing river quality from one river to another and for looking at changes through time.
For the chemistry and nutrient ‘windows’, about 7,000 river and canal sites are sampled 12 times each year. The classification is based on 36 samples, that is, the results for three years are combined. So the classification for the year 2000 includes the sample results for 1998, 1999, and 2000.
We have overlain our national GQA map and a map of SSSIs to find out which SSSIs do not have good or very good water quality. These maps are at different scales so there is only a rough match in the definition of river stretches. The statistics are only indicative national figures; they have not been checked at local level.
GQA classification methods
Samples are analysed for three determinands of organic pollution: ammonia, biochemical oxygen demand (BOD), and dissolved oxygen. The results for a site over three years are combined and percentiles are calculated. These are compared with limits set for each of six grades – A to F. A grade is assigned to the length of river (which the sampling site represents) according to the lowest grade achieved by any of the three determinands. For example, if a site is grade A for dissolved oxygen and ammonia but only grade B for BOD then the grade assigned is B.
In 2002, a third of all sites were tested for their biological quality. The macro-invertebrates (small animals that can be seen with the naked eye) found in the kick-samples taken are identified. The range of species found is compared with the range that would be expected in the river if it was not polluted or physically damaged. This takes account of natural differences expected due to different types of geology and flow, for example. One of six grades – A to F – is allocated to each river length.
Samples are analysed for nitrate and orthophosphate. A grade is assigned for each of these nutrients. There are no set ‘good’ or ‘bad’ concentrations for nutrients in rivers in the way that we describe chemical and biological quality. Rivers in different parts of the country have naturally different concentrations of nutrients. ‘Very low’ nutrient concentrations, for example, are not necessarily good or bad; the classifications merely states that concentrations in this river are very low relative to other rivers.