Estimating Transmissivity From the Water Level Fluctuations of a Sinusoidally Forced Well

141 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998.These new methods were tested using generated and field data. Using the generated data, the new methods reproduced the known values of T, even when modest levels of noise were included. For the field data, the amplitude and damping ratios were determined, and transmissivity was estimated. These data were also analyzed with the frequency domain approach of Rojstaczer (1988). The estimates of T determined using nonlinear regression, time series analysis, and Rojstaczer (1988) were consistent in the absolute and relative magnitude for both wells. However, the estimates of transmissivity determined with these three methods were generally lower than the values determined by field methods (slug tests, pump tests, and a packer test). These differences in T may be explained by differences in the radius of investigation of each test and the geologic heterogeneity. Testing these new methods with additional field data is suggested. Atmospheric tides and earth tides can cause the water level in a well to oscillate in a sinusoidal fashion. Two new methods for estimating transmissivity (T) from the analysis of these water-level oscillations were developed. The goal of this thesis was to improve upon the available methods for analyzing these data by developing a simplified, time-domain solution.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD