Analysis of percipitation and saturated thickness of the Texas Ogallala Aquifer

The Ogallala Aquifer is an important source of groundwater for agricultural and municipal supplies on the Texas High Plains. It is widely recognized that water levels in the aquifer are declining at an average rate of about one foot per year. Declining aquifer water levels are a result of water extraction occurring faster than aquifer recharge. Although the water levels of the aquifer are declining, the rate of decline fluctuates year-to-year and it seems reasonable to assume that variations in annual or seasonal precipitation contribute to the variability in the rate of decline. The precipitation rates affect the amount of water extracted by producers for irrigating crops. To address this problem, the objective of this thesis was to determine if precipitation has an effect on the rate of water extraction from the Ogallala Aquifer. This study compares the annual change in saturated thickness with precipitation data for the study area to determine the relationship between aquifer drawdown and precipitation. Well data for the Ogallala Aquifer were acquired for 1990 to 2008 for 10 counties on the Southern High Plains. The well data were used to calculate saturated thickness and rate of decline for each year. The saturated thickness was compared with annual and seasonal precipitation totals for each year. The results from this study found that annual precipitation amount has a statistically significant effect on the rate of decline of saturated thickness of the Ogallala Aquifer in Texas. Furthermore, seasonal precipitation will have a greater effect on the rate of decline of saturated thickness than annual precipitation.