Document Type


Publication Date

January 1984


This report describes the development, calibration and use of quantitative, predictive management model for the groundwater in the Utah portion of the Cache Valley in northern Utah. The quasi-three-dimensional finite difference computer model was adapted from the U.S. Geological Survey’s Trescott and Larson model and simulates the groundwater levels and flows in the groundwater basin. The variable spacing grid system is 23 nodes x 38 x 2 and represents the complex natural system by a simpler approximation with one unconfined and one confined aquifer and the appropriate boundary and initial conditions. River nodes, spring nodes, and constant head nodes were developed to simulate the real interactions of the aquifers with streams, springs and reservoirs. Evapotranspiration from the land surface is also represented by the program. The program was calibrated by adjusting the model parameters such as transmissivity, storativity, leakance, river nodes, spring nodes, etc. until the predicted values of head and flow were nearly the same as the observed conditions. Calibrations with 1969 conditions and then a transient-state comparison with the water level change maps of 1969 to 1972. The calibrated model was then exercised to predict the groundwater system response to various assumed scenarios of groundwater recharge and draft. Thus the model provides a tool to guide future groundwater development and management towards the best alternatives.