ANALYZING NATURALLY-INDUCED STRESSES TO DETERMINE THE STORAGE COEFFICIENT OF THE ARBUCKLE-SIMPSON AQUIFER

The water yielding capacity of a confined aquifer is represented by its storage coefficient. The storage coefficient and transmissivity are the essential hydraulic parameters required as input for groundwater management and flow models. The standard method for determining the aquifer storage coefficient is through pumping tests, however these are costly and site specific. Mechanical forcing of the aquifer by ocean tides, earth tides, and pressure fluctuations in the atmosphere stress the aquifer and cause water level fluctuations. The tidally and barometric pressure-induced water-level fluctuations within a well are a function of the aquifer hydraulic parameters, well parameters, natural stress frequencies and amplitudes. The well water-level fluctuations were analyzed to determine the specific storage and storage coefficient of the Arbuckle-Simpson aquifer. Data from 14 wells of variable depths and variable time intervals were employed for the analyses. The data vary with depth in an aquifer that is greater than 1000 m thick in places. The average values of the specific storage and storage coefficient are 1.11E-5 m-1 (3.32E-6 ft-1) and 0.124 respectively.