Simulated changes in ground-water levels related to proposed development of Federal coal leases, San Juan Basin New Mexico

The effects of coal-related ground-water withdrawals on potentiometric surfaces of aquifers in the San Juan Basin, New Mexico, were estimated. A previously published steady-state finite-difference digital model was converted to a transient-state model by changing boundary conditions and adding storage coefficients. No calibration of the transient-state model was attempted. Predicted drawdowns with a minimum amount of coal development combined with other kinds of development were as great as 2,000 feet. As much as 300 feet of additional drawdown were simulated for the maximum amount of coal development. Drawdowns near pumping wells are not predicted. (USGS)