Monitoring of waters intended for abstraction

The National Rivers Authority (NRA) monitors rivers for many different purposes. Routine monitoring for specified national and international purposes only serves to categorize the water in the general sense and is unlikely to detect short term quality aberrations. Where rivers support potable abstractions additional monitoring may be required to supplement the more routine data collection. Experience on the River Dee which straddles the North Wales and English border indicates that it is possible to construct a monitoring system that offers a high degree of protection against adverse quality changes but that such protection is both costly and complex and cannot guarantee absolute protection against all foreseeable events. Improved pollution control, the establishment of catchment inventories and protection zone status for sensitive areas may be effective in reducing the risk further. Cooperative investment in monitoring by the NRA and the Water Companies is very effective although differing expectations and standards can produce problems.