222893e

INTERNATIONAL COOPERATION ON WATER SCIENCES AND RESEARCHSharing water observations: turning localdata into global informationDr Harry Dixon, Professor John Rodda and Professor Alan Jenkins,Centre for Ecology and Hydrology, UK; Professor Siegfried Demuth, United Nations Educational Scientificand Cultural Organization; and Ulrich Looser, Federal Institute of Hydrology, GermanyMinimizing risks of losses or injury to individuals,businesses and communities is a shared goal of scientificinstitutions, public and private enterprises andgovernment. In terms of natural hazards, some of the mostserious sources of risk emanate from floods, droughts and tropicalstorms. To combat these and similar events it is vital tomeasure their severity, frequency and extent, to record thesedata, then to apply and disseminate them.Data describing the freshwater environment are employed for a greatvariety of practical purposes which have changed with time. Floodprevention was one of the earlier uses of rainfall and river flow datawhile the development of canals, hydropower and reservoirs followed.Control of water pollution required water chemistry measurements andthese are also needed with observations of rainfall, run-off and groundwaterlevels for water resources management. Evaporation and soilmoisture measurements are valuable for irrigation. Robust, lengthy andvaried hydrometeorological measurements are central to global changestudies. Employing reliable data to forecast, predict andunderstand hydrological processes reduces risk in each ofthese contexts: risk of failure through inadequate designand risk of financial loss.Collecting reliable and representative hydrometeorologicaldata, however, is difficult. The naturalenvironment is hostile to instruments; conditions arecontinually changing. Measurements of extremes, suchas heavy rainfalls and flood peaks, are particularly problematical.They are best made over long time periods andpoint measurements should be representative areally.With the advent of observations from satellites andweather radar the problem of spatial coverage has beeneased, but such technologies do not currently offer thelevels of accuracy required for many uses. As a result,ground-based measurements of the water cycle remainsome of the most essential environmental data collectedaround the world. At the core of such water data lieImage: Rivers Agency, Northern IrelandRiver flow gauging on the River Blackwater in Northern Ireland during a flood event in November 2009[ 304 ]