Understanding Drought

Many people have many different ideas about what drought is. While drought is a normal part of climate changes that effects almost all climate zones, its characteristics vary according to region.



Drought is technically a deficiency of precipitation over an extended period of time. Without replenishing rains, areas experiencing drought can experience drinking water shortages, ground water shortages and more.



Drought is measured against an areas average balance of precipitation and evapotranspiration. If this measurement is below normal, the area is considered to be experiencing drought. Timing and climatic factors are also taken into consideration when an area is measured for normal conditions. Climatic factors include high temperature, high wind, and low relative humidity.



Drought is broken down into various terminologies. These terms include:



Meteorological Drought - This type of drought is defined on the basis of the degree of dryness (in comparison to some "normal" or average amount) and the duration of the dry period. As mentioned above, there are a number of considerations to take when determining what is normal or average in any given area. Other definitions may relate actual precipitation departures to average amounts on monthly, seasonal, or annual time scales.



Agricultural Drought - This type of drought links various characteristics of meteorological (or hydrological) drought to agricultural impacts. The focus with this definition of drought looks at rain shortages, soil water deficits, reduced ground water and reservoir levels and such. Agricultural drought measurements looks at how crops are affected, how topsoil can be deficient in moisture which in turn hinders germination, and how subsoils are deficient in moisture.



Hydrological Drought - Hydrological drought is associated with the effects of periods of precipitation (including snowfall) shortfalls on surface or subsurface water supplies (i.e., streamflow, reservoir and lake levels, ground water). Yes, drought is measured not only by rain but also snowfall. To measure this type of drought, watersheds or river basin scales are measured as is ground water and reservoir levels. Hydrological drought measurement results are not shown as quickly as agricultural drought. Measurements take longer to show problems compared to obvious results that agricultural drought can show such as stream flow and soil moisture. Agriculturalists can discern drought quite quickly while hydrologists may take longer to prove hydrological drought.





Measuring an area and comparing it to its drought history is another important form of data collection. While today scientists can gather information through weather stations, they can also look at climate conditions through tree-ring analysis and paleo-climate records. Such records have shown drought occurring throughout the United States throughout time. There is even evidence of what is called mega-droughts, that is droughts extending past 20 years. These droughts are shown in 1000 A.D. and 1300 A.D. The problem with droughts from then and now is the amount of people living in the United States and their water use.





Drought conditions not only stress water supplies but also agriculture, energy production, increase fire risk, affect water and air quality and species preservation.





While scientists cannot determine exactly when a region will experience drought, they do know it does occur over and over and can occur at any time - thus making everybody take a new look at how water, now, should be used.



Carolyn Boden is a marketing consultant at Belvedere, Texas hill country land for sale real estate community. They sell beautiful hill country acreage located west of Austin near Hamilton Pool. For more information please visit http://www.belvedereaustin.com.