Removing the Confusion Over Droughts and Floods: The Interface Between Scientists and Policy Makers

Droughts and floods, as precipitation excesses, are quite different natural hazards, and each costs the United States more than $1 billion in losses annually. At the impact and policy levels, confusion arises from an inability to define droughts suitably and to identify flood losses in a quantitative way, unaffected by population changes, land use shifts, and other socioeconomic factors. Examples from Illinois research are used to show how relationships can be developed between generally understandable precipitation values and drought or flood losses in various economic sectors and land use areas. Then, the time and space variations of the events can be objectively assessed by using the precipitation data, providing meaningful scientific-engineering definitions for use by decision makers.