River basin characterisation is a key step in the implementation of the 2000 Directive. Competent authorities are required to examine all of the pressures and impacts on water bodies and assess the risk of waters failing to meet good ecological status, or good ecological potential in the case of heavily modified or artificial water bodies.
The information will be used to design a monitoring programme, river basin management plans and measures to ensure that good ecological status is achieved by 2015.
Rivers, lakes, estuaries, coastal waters and groundwater are all included in the process. The exercise involved 18 months' work by Agency water quality and geographic information systems experts. It pulls together data held not only by the Agency, but by English Nature, the Countryside Council for Wales and research bodies, together with information on farming practices from the Environment Department (DEFRA).
The exercise has to be completed this year, and the Agency is following in the wake of the Scottish Environment Protection Agency, which began a formal consultation on river basin characterisation in July (ENDS Report 354, pp 50-51 ). Both regulators need to deliver reports to DEFRA by December.
The Agency has produced a series of some 70 maps, each coloured in shades of pink and purple, with the darkest tones showing where the risk of failure is greatest.
The maps are available on the Agency's website.1 The Agency has decided not to conduct a formal consultation but is asking for initial views on whether the maps contain significant errors. It is also requesting detailed comments or suggestions of more data which might improve the maps by the end of November.
The Agency intends that the maps represent a first pass and will be refined before 2009 when improvement programmes - likely to involve action by farmers, water companies, dischargers and abstractors - will be designed and implemented.
"We are putting the maps in the public domain as a quality assurance loop," Mr Griffiths said. "We want to have final versions by 2005 but we will continue to refine them until they become the basis for spending and investment in 2009."
It is important to recognise that these maps deal purely in probabilities because the Directive's goal of good ecological status has yet to be defined (ENDS Report 347, pp 22-25 ). They are "characterisations" rather than "classifications" and do not reflect current water quality.
The maps show only where pressures likely to reduce water quality are most intense. The maps also incorporate information on protected areas where special water quality standards apply to protect habitats, drinking water supplies, freshwater fisheries, shellfish, bathing waters, and nutrient sensitive sites - each of which is protected under specific EU legislation.
An example is the map of pressures on rivers from point sources of nutrients (see figure 1), which was constructed from information on the permitted levels of phosphate and nitrate in discharge consents and the average flows of each river. It shows where the concentrations of substances are likely to exceed the most stringent targets for each water body.
The map of pressures on groundwater from diffuse sources of nitrate (see figure 2) was constructed from existing nitrate levels in aquifers, combined with estimates of loading from current agricultural and atmospheric sources, and allows for the vulnerability of each aquifer.
Considering the breadth of the good ecological status goal, and the number of potential threats - abstraction, acidification, diffuse urban and agricultural inputs and point source discharges and the modification of river channels - it is perhaps not surprising that few waters escape the risk of failure.
The aggregated data show that no rivers, estuaries, groundwaters and coastal waters escape some risk of failure (see table). Two-thirds of lakes, over 80% of rivers, 95% of estuaries and over a third of groundwaters are in the highest-risk category.
The data also tend to overstate the problems, with failures in short stretches of rivers causing a failure in the whole water course. There is also scope in the Directive for lower standards in artificial or heavily modified water bodies.
Point source discharges remain a major threat, the Agency's analysis shows. Some 40% of rivers and 68% of estuaries are at risk because of them. Diffuse nitrogen inputs threaten 46% of rivers and 15% of groundwaters. Another 30% of groundwaters are "probably at risk".
The figures are considerably worse than in Scotland, presumably reflecting the higher population density and greater area of intense agriculture south of the border.
The water industry in England and Wales is also much less favourably placed than Scottish Water to meet the investment required by the Directive. Scottish Water's investment plans will allow for investment from 2006, while south of the border companies will have to wait until the fifth asset management period in 2010.
This will leave only five years to implement measures and achieve good ecological status - a considerable challenge.
The Directive requires DEFRA to submit the corrected river basin characterisations for the whole of the UK to the European Commission by March 2005.