Fighting floods

the Institute of Hydrology (ih), England, has developed a hydrological radar system which combines weather radar and rain gauges to estimate rainfall over river catchments in the past, as well as forecasts of future rain. Data is fed into the River Flow Forecasting System (rffs) which provides forecasts of possible river flooding across a region. The system can be applied to any river network. New models, relevant to a specific area can be easily added. This versatile system is currently used for forecasting river flows throughout Yorkshire in Glasgow ( nerc News , Summer 1997).

As it is impossible to protect fully against flooding, an early warning system is vital. Much of the information needed for flood warnings is collected automatically from river gauges, tide monitors, rain gauges and the instruments at tidal barriers. The rffs receives the data by telephone links and feeds it into models for catchment runoff, channel flow routing, and tides. If the system suggests that flooding is likely, the Environment Agency issues flood warnings and thus protects life. Property can also benefit from this warning as the radar system allows river and tidal control systems to be activated at critical points.

Floods have caused damage and distress on a wide scale killing nearly 2,00,000 people in the last ten years. ih is investigating three main aspects of flooding -- flood estimation, flood forecasting and flood estimation, flood forecasting and flood-risk mapping. The work is funded mainly by the ministry of agriculture, fisheries and food and the environment agencies.

ih is also developing a flood-risk mapping on a national scale. Such mapping is essential for engineers and planners when considering new developments. More accurate mapping requires hydrologists, engineers, surveyors and cartographers. The new methods will enable engineers and planners to make decisions, and help protect lives and economies at risk of flooding.