One of the cornerstones of drought planning is to develop a local drought history. A local drought history should include information about both climatology and impacts.
Climatology provides benchmarks about a location’s climate, such as the drought of record. The drought of record is the drought remembered as having the greatest impact on a region. Most of us are not consciously aware of how much the climate fluctuates from one decade or century to the next. One way for reservoir managers, municipal water suppliers, and other planners to compare their expectations with reality is to examine their region’s drought of record. But caution is necessary here: Although the weather conditions could recur, the impacts would likely be very different. For most of the country, the drought of record was 30 to 60 years ago, and population concentrations and water use patterns have shifted substantially since then.
Specifically, climatology answers crucial questions such as:
- How much precipitation normally occurs and what time of year is it most abundant?
- How often does drought occur in this region?
- How severe have the droughts been?
- How widespread have the droughts been?
- How long have the droughts lasted?
Knowledge about historical drought impacts helps describe a location’s vulnerability to drought. It also helps determine the kinds of measures that planners and policymakers need to implement to prevent impacts from recurring.
Important questions about drought impacts include:
- What hydrological, agricultural, and socioeconomic impacts have been associated with the various droughts in the past? (The Impacts Checklist may be helpful.)
- Who are the major water users in the community, state, or region?
- Where does our water supply come from and how would the supplies be affected by a drought of record?
- What would happen if the drought of record occurred here now?