Drought Frequently Asked Questions
Q: What is Drought?
A: Drought is a prolonged period of below-average precipitation severe enough to negatively impact the environment and human activities. Drought is a natural occurrence and Arizona is especially sensitive to drought, since water is scarce here even during average years. Population growth continues to increase demand for water. Drought can impact domestic water supplies, ranching and farming production, vegetation, forest health and wildlife populations.
Q: Is Arizona currently in a drought?
A: Arizona has been in some stage of drought since 1994, according to statewide precipitation patterns. Drought conditions can have an impact on Arizona's water supplies. Unlike hurricanes and tornadoes, drought does not cause immediate, visible results; however, it can be as devastating as any other natural disaster. Arizona's current short-term and long-term drought conditions are available here. Current drought declarations are available here.
Q: How does Arizona plan for drought?
A: Arizona has been actively planning for and addressing drought conditions and impacts through several avenues: drought working committees, water use reporting requirements, Colorado River shortage preparedness and the Arizona Water Initiative. Read more about Arizona drought planning efforts here.
Q: How do we know when the drought is over?
A: Based on statewide precipitation patterns the current drought in Arizona started in mid to late 1990s. In order for this drought to be over, a series of above average precipitation events, especially during winter and specifically in the form of snow, are needed; one wet winter is not enough to rehydrate the soil and vegetation, which have been receiving less than average precipitation for over 20 years. Snow is specifically important because it functions as a natural water reservoir, storing water on top of the mountains in the winter when there is less demand for it, and gradually releasing it in the form of runoff during spring and early summer, when water demand is higher. Snow and the steady runoff it provides is often more beneficial than rain, which is often more temporary, in recharging streams and groundwater.
Q: What are the methods for determining drought status?
A: The Monitoring Technical Committee uses percentile values for precipitation and streamflow to determine drought status in each of Arizona’s watersheds. Arizona’s long-term drought status map, updated quarterly, incorporates 24-, 36- and 48-month precipitation and streamflow percentiles from multiple gages in each of Arizona’s major watersheds. To arrive at these values, precipitation and/or streamflow totals for each period (24, 36, 48 months) are compared to a 40-year historical record. For more information see these resources:
Q: If it rains where I live, why does the drought map still reflects drought in my area
A: Water resources in Arizona are diverse and can arrive from hundreds of miles away; such is the case with the Colorado River water. Water in the Colorado River are generated by snowmelt runoff from mountain ranges that can be located in as far as Colorado and Wyoming states, upper in the Colorado River Basin. Even water supplies that are generated within the state can originate much further than the place of consumption- either located deep underground (in the form of groundwater) or generated by snowmelt from mountains located tens of miles away from Central Arizona, where most of the state's residents live and work. Therefore, precipitation in one's local area may have little to no effect on the water that ends up pouring from one's tap.
Q: How drought status for adjacent watersheds can differ by two or more drought categories?
A: Occasionally, the drought status of adjacent watersheds on the long-term drought status map will differ as much as three drought categories, as seen in the southwestern corner of the sample map. This is because each watershed reflects the average for the precipitation stations within that watershed, and most of the watersheds have very few gages. The sharp boundaries are misleading, as the drought does not end at a watershed boundary. Rather, the impacts gradually transition from one watershed to another. Eventually, when we are able to use gridded data for calculating the Standardized Precipitation Index, the boundaries between drought categories will be more gradual and less stark.
Q: Why aren't there statewide restrictions on water use in Arizona?
A: Though there are no statewide water use curtailments, during shortage conditions, some local areas may have ordinances that ensure that unreasonable use of water resources is prevented and conservation of water is accomplished. Furthermore, regulations for both surface water and groundwater assert that water should only be used for beneficial purposes. Additionally, various users in active management areas have restrictions on the volume of groundwater that may be withdrawn, the maximum groundwater withdrawal rate, and/or conservation requirements based on the particular water-using sector.