Abstract

A water budget is presented for the Powder Mountain region of Utah using a hydrologic equilibrium water-balance approach. The Powder Mountain study area includes eight adjacent sub-basins in Cache and Weber Counties. Data from the discrete basins collectively provide initial estimates of existing water budget conditions in the Powder Mountain region. The principal water budget components include: precipitation, runoff, spring discharge, evapotranspiration, bedrock underflow, and channel seepage. Methods used to construct the water budget are outlined and the calculations and assumptions are provided. This analysis is a conceptual level generalization based on limited site-specific data.

Placing a new stress on the Powder Mountain system from ground-water development will result in adjustments that may include removal of ground water from storage, capture of: discharge or “rejected” recharge, and increase in aquifer recharge.

Water budget analysis is a valuable tool for evaluating basin hydrology; however, aquifer recharge estimates should not be the basis for determining the size of sustainable ground-water developments. Aquifer sustainability is directly dependent upon the dynamics of the system and the ability of the aquifer to balance production with an increase in aquifer recharge, a decrease in discharge, or removal of ground water from storage. Water budget estimations should be flexible and updated as site-specific data are collected. Perhaps the best use of water budgets is to provide a framework for more detailed studies, locating gaging or monitoring stations, and computer simulations that assist with the goal of monitoring the resource.