Effects on streamflows and ground-water levels attributable to a proposed intermittent change in use and sites of withdrawal of 3 ,146 acre-feet of water from the Arikaree aquifer in central Platte County, WY, are assessed with a previously developed ground-water flow model. This water has been permitted for agricultural use by the State of Wyoming, and under the proposal would supplement, when needed, existing industrial surface- and ground-water supplies for the Laramie River Station of the Missouri Basin Power Project. Under a scenario wherein the supplemental industrial usage occurs in every 10th year commencing in 1980, the model predicts a cumulative streamflow-depletion rate in the Laramie and North Laramie Rivers of 7.7 cubic feet per second in the year 2020 compared to a rate of 6.9 cubic feet per second that is predicted if the intermittent industrial usage does not occur. Areas in which drawdowns relative to the simulated 1973 head configuration exceed 5, 10, 25, and 50 feet are predicted to be 107, 78, 38, and 2 square miles, respectively, in 2020 under the intermittent-usage scenario compared to corresponding areas of 104, 76, 36, and 2 square miles that are predicted if the intermittent industrial usage does not occur. (USGS).