No comparable measures were available for the US and Canada. Biological water quality. Over 90 per cent of rivers and canals are classified as being in 'fair' or 'good' condition by the Environment Agency. An assessment of the quality of water based on various chemical and biochemical measures. Total renewable freshwater water availability in Britain is about 76 billion cubic metres.
Availability fluctuates according to weather patterns there but is no apparent long-term change.
Total use decreased by approximately thirty per cent between 1980 and 1995, from about 13 to about 9 billion cubic metres. Water quality has been gradually improving in the UK since measures began. As with air quality, this is in part because of regulatory restrictions on emissions. However, levels of phosphorus and nitrogen may still be higher than is desirable in certain areas. One reason for this is subsidies to agriculture, which encourage the overuse of nitrogen and phosphorus fertilisers.