The phreatic or potentiometric surface is assumed to be level prior to pumping.
Pumping test data can also be used to calculate a radius of influence, which is the distance at which there is negligible change in the phreatic or potentiometric surface between static and pumped conditions.
Aquifer thickness 26 m Height of static potentiometric surface above the top of the aquifer 85 m Drawdown at 20-m radius 35 m Drawdown at 100-m radius 5 m Aquifer medium mixed sand hydraulic conductivity = 2 x [10.
Rettman (1983) measured the water levels in the Evangeline in the Kingsville area during 1982 and found a large cone of depression in the potentiometric surface which occurs below Kingsville.
The specific objectives of this study were to: (1) simulate the potentiometric surfaces computed by Groschen (1985); (2) determine the effects of groundwater withdrawals from uranium mining operations on the potentiometric surface of the Evangeline aquifer; (3) test several boundary conditions used by Groschen (1985) in a 38-row by 38-column grid model and determine the appropriate use of the boundary conditions; and (4) determine if there may be any significant dewatering of the Evangeline Aquifer due to in situ leach mining operations at the Kingsville Dome plant (currently in restoration phase).
The potentiometric surface as defined by Groschen (1985) is the elevation at which groundwater levels would stand in tightly cased wells.
The fluid flow for the Evangeline Aquifer in the study area was modeled to examine the following: (1) the transient-state effects on the potentiometric surface for the years 1983-2020; (2) the effects that potential pumping from uranium mining operations at the Kingsville Dome would have on the groundwater resources in the future; and (3) the results of a sensitivity analysis on Groschen's (1985), no-flow boundary conditions on the east and south sides of the modeled area.
The steady state simulation was performed to simulate the initial potentiometric surface, and the steady-state model is calibrated to Groschen's 1901-1982 data.
Computer simulations were also conducted to determine the effects from the mining uranium on the potentiometric surface for high withdrawals at 9625.
Comparison of the computed potentiometric surface to Groschen's (1985) results, simulated with the use of Konikow & Bredehoeft's (1987) Method of Characteristics (MOC) simulation model, reveals no significant differences with the exception of increased drawdown at the eastern no-flow boundary (the zero elevation contour is closer to the eastern no-flow boundary).