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Drought Discussion and Planning
Department of Renewable Resources
University of Wyoming
When discussing drought the first problem that comes up is that every person in the room is likely to have a different interpretation of what drought means. A definition of drought depends on expectation and emphasis. If a little time is spent at the start of a conversation to clarify an understanding of these two elements of drought, then I find the discussion usually goes much more smoothly.
Expectation implies anticipation of normal; if precipitation is dramatically below expectation a drought is declared (e.g., the Society for Range Management definition of drought is less than three-quarters of the average annual precipitation amount). Many people develop their management plans around what is "normal" and they calculate "Norma" as the arithmetic mean (i.e., summing annual precipitation data and dividing by the number of years). This is NOT an appropriate way to calculate "Norma" because annual precipitation data in Wyoming is usually highly skewed (e.g., many dry years and a few very wet years). The degree of skewness generally increases as the climate becomes drier because occasional meteorologic conditions produce unusually heavy rainfall for a few years of the record. The correct way to calculate "normal" is to use the median (i.e., the mid-point of the data set, where half of the years are wetter and half are drier) or the mode (amount of precipitation that occurs most often in the data set). This also applies to calculating things dependent on precipitation such as "normal" forage production. As you can see, if normal is calculated correctly, we would not hear the oft-stated comment that "in this country we are in a drought most of the time" -- such a statement is nonsense because it implies that the speaker has a skewed perception of the amount of precipitation that can be expected. It follows that the person would also have a skewed expectation of things related to precipitation such as normal forage production or stocking rate. Obviously such fundamental misperceptions can be dangerous. Drought is an inevitable part of climate fluctuation and should be considered as a recurring, albeit unpredictable, environmental feature which must be included in planning.
Emphasis refers to what is most important to the manager. In rangeland settings, the amount of precipitation is not as important as how that translates to forage and drinking water availability. Depending on the snowmelt and rainfall pattern characteristics, it is not unusual to have plenty of forage but no water in streams or stockponds (i.e., a hydrologic drought) or no forage but plenty of drinking water available (a forage drought). Management response to these two different types of drought should be quite different. Because hydrologic drought is much more prevalent on Wyoming rangelands than forage drought, a proactive response to planning for hydrologic drought would be to maintain/develop water sources to keep livestock dispersed on the landscape as long as possible, thereby delaying the time when they forced to retreat to the limiting few permanent water sources on the landscape. Another prudent action would be for the rancher and land management agency to agree on (and obtain pre-approved ecological and archeological site clearances) where water could be hauled when a hydrologic drought exists. These sorts of actions should be taken before a drought begins allowing for planning and follow-through actions to occur in the context of risk management instead of waiting and dealing in an ad hoc matter with crises.
Droughts are a natural part of climate and are certain to occur, therefore droughts should be expected. It is disingenuous to use the unpredicability of drought as an excuse for inadequate planning decisions that have failed to take rainfall variability into account. Exposing the land to accelerated erosion hazard should be viewed as a managerial failure, instead of making drought a scapegoat for faulty land management policies.
Since droughts are certain to occur it would seem obvious that every government allotment management plan and every ranch plan should have a serious strategy developed for responding to the various types of drought. Very few plans do. Why? Policy-makers and land managers persist in treating drought as a quirk of nature because if they accept the challenge of developing substantive drought management plans, then they implicitly accept responsibilities associated with the development and implementation of proactive responses to drought. These are difficult responsibilities to bear because the costs of planning for drought are fixed and occur now while the costs of degradation from drought are uncertain and occur later. Therefore it is in the interest of many who profess to be committed to sustainable land management to characterize the consequences of drought as something exceptional, thereby portraying drought as a temporary, climatic aberration. Consequently, each time a serious drought occurs it is handled as an abnormal event and not taken seriously in planning once expected rainfall patterns resume. As a professional society interested in sustainable rangeland management it seems that we need to step up to the plate and be more forthright in advocating for substantive drought management planning and then, of course, require follow through with the plan implementation for private and government lands. To create and environment that will allow these plans to succeed, market risk management planning is also needed along with development of more proactive risk management policy of state and federal government.
One benefit of World Wide Web is that information on climate and water supply is much more accessible than ever before. One problem with the World Wide Web is finding the information. Agencies such as the National Oceanographic and Atmospheric Administration (NOAA) have made great strides in recent years in reporting and getting better at forecasting relevant information, thereby undercutting the excuse that lack of information fosters hopeful inaction. Below are some of the sites that I find most useful in characterizing various aspects of drought.DROUGHT STATUS