AWWA ACE58146

Dealing with the curtailment of water supplies during drought is frequently the most refractory problem faced by water utility management. The timing, duration, and severity are always uncertain. Drought contingency plans of progressive water utilities are marked by four consistent and dominant characteristics. First is an accurate evaluation of the dependable yield of available supplies which reflects the vagaries of nature, environmental constraints, operating limits of facilities, and interdependence among sources of supply. The second hallmark is that water requirements are projected with technologies that fully reflect the potential variation in demand. The third characteristic of a sound drought contingency plan is that the increasing severity of drought and reduction in available supply is matched with measures to reduce water demands. The fourth, and final, single characteristic is that the plan has flexibility in application as all conditions during a drought can't be predicted beforehand. A drought contingency plan based on the "drought of record" provides useful guidance, but any subsequent drought will have a different pattern and require a different response. Approaches for and characteristics of drought contingency plans are illustrated in this paper through two case studies. First is a Midwestern city of 225,000 residents using alluvial groundwater for supply. Second is an Eastern utility with four reservoirs for supply. Includes tables, figures.