   Is the Drought Over? - June 8, 2005 Jeff Schalau, County Director, Associate Agent, Agriculture & Natural Resources Arizona Cooperative Extension, Yavapai County Our generous winter and spring precipitation brought some temporary relief to the drought conditions we’ve been experiencing in north central Arizona. Above average streamflow, mostly from snowpack in northern New Mexico, has eased the hydrologic drought conditions in the Colorado River drainage. Lake Powell storage will continue to increase through July, but both Lake Powell and Lake Mead are currently well below capacity. Now brace yourself: summer season forecasts are predicting above average temperatures and below average precipitation through the summer for the Arizona. The above information comes from the May 2005 Climate Outlook published by the University of Arizona Climate Assessment for the Southwest (CLIMAS). The CLIMAS Project is located within the Institute for the Study of Planet Earth, is one of several initiatives that have been funded as pilot projects by the National Oceanic and Atmospheric Administration's (NOAA) Office of Global Programs. Each month, a new Climate Outlook is published and available on-line at: www.ispe.arizona.edu/climas/. These monthly reports integrate several sources of research-based information and observations to create an interesting and understandable publication. CLIMAS researchers warn us that we are very likely still in the midst of an extended drought period. Drought has been described in various ways, but most climatologists characterize drought in four different ways: meteorological, agricultural, hydrological, and socioeconomic. The first three characterizations deal with ways to measure drought as a physical phenomenon. The fourth deals with drought in terms of supply and demand, tracking the effects of water shortfall as it ripples through socioeconomic systems. Below are detailed descriptions. Meteorological drought characterizes a decrease in precipitation from normal over some period of time for a given geographic region. Meteorological drought is region-specific and requires a thorough understanding of regional climatology. It cannot be use to compare widely disparate regions of the world to one another (i.e. tropical areas to temperate areas). Agricultural drought occurs when there isn’t enough soil moisture to meet the needs of a particular crop at a particular time. Agricultural drought happens after meteorological drought but before hydrological drought. Agriculture is usually the first economic sector to be affected by drought. Hydrologic drought is most often defined in terms of reduction of streamflow, reduction in lake/reservoir levels, or lowering of ground-water tables. There is a time lag between lack of rain and less water in streams, rivers, lakes, and reservoirs, so hydrological measurements are not the earliest indicators of drought. When precipitation is reduced over an extended period of time, this shortage will be reflected in declining surface and subsurface water levels. Socioeconomic drought occurs when physical water shortage starts to affect people, individually and collectively. Or, in more abstract terms, most socioeconomic definitions of drought associate it with the supply and demand of an economic good. Drought impacts also influence wildfire risk. In Arizona, a wet winter translates into increased wildfire risk in the desert areas due to increased fine fuels from herbaceous vegetation. Extended dry periods increase wildfire risk at the higher elevations. A drier than average summer will increased wildfire risk in north central Arizona, but for now the greatest wildfire risk is still in the desert. Understanding our climate and how affects us is crucial to our ability to create sustainable communities in the arid southwest. We need to conserve and value our water resources at all times. We should continue to utilize xeriscape principles, water harvesting, mulching, and efficient irrigation methods. I also encourage you to visit the CLIMAS Web Site mentioned above. One final note: I will not be able to make my scheduled office hours in the Cottonwood office on June 20. My next scheduled date for office hours is July 5 between 9 AM and 4 PM. The University of Arizona Cooperative Extension has publications and information on gardening and pest control. If you have other gardening questions, call the Master Gardener line in the Cottonwood office at 646-9113 ext. 14 or E-mail us at mgardener@verdeonline.com and be sure to include your address and phone number. Find past Backyard Gardener columns or submit column ideas at the Backyard Gardener web site: http://ag.arizona.edu/yavapai/anr/hort/byg/. |