Drought is a hazard that defies a universal definition. Typically, drought is a shortage of water associated with a deficiency of precipitation. However, water shortages can also be induced by humans. Perhaps it is easier to think of drought as being a function of supply versus demand.
Drought occurs when a normal amount of moisture is not available to satisfy an area’s usual water-consuming activities. Drought is a frequent visitor to our semiarid state. The most significant impacts which typically confront the state are related to such water intensive activities as: agriculture, wildfire protection, municipal usage, commerce, tourism, recreation, and wildlife preservation. A reduction of electric power generation and water quality deterioration are also potential problems.
Idaho’s arid climate predisposes it to periodic drought. Some areas of the State, however, have a greater potential for drought than others. The Idaho Department of Water Resources reports that based on analysis of historic stream flow records, southeastern Idaho and the upper portions of the Snake River Plain appear to have the highest probability for persistent, severe stream flow deficits.
In 1977, the worst single year on record, a severe water shortage occurred throughout Idaho and the west. Area ski resorts were closed much of the season. A lack of winter snowfall resulted in the lowest runoff of record at most gages in the State. Irrigation ditches were closed well before the end of the growing season and crop yields were below normal. Domestic wells in the Big and Little Wood River Basins became dry early in April 1977 and many shallow wells in six western Idaho counties became dry in June. This year of drought led to a Federally Declared Disaster for nine counties in Idaho. Cyclical patterns of moisture and precipitation would seem to indicate that Idaho will continue to experience drought.