Outflow from Bull Shoals Lake and other White River reservoirs supports a cold-water trout fishery of substantial economic yield in north-central Arkansas and south-central Missouri. The Arkansas Game and Fish Commission has requested an increase in existing minimum flows through the Bull Shoals Lake dam to increase the amount of fishable waters downstream. Information is needed to assess the impact of increased minimum flows on temperature and dissolved-oxygen concentrations of reservoir water and the outflow.A two-dimensional, laterally averaged, hydrodynamic,
temperature, and dissolved-oxygen model was developed and calibrated for Bull Shoals Lake, located on the Arkansas-Missouri State line. The model simulates
water-surface elevation, heat transport, and dissolved-
oxygen dynamics. The model was developed to assess the impacts of proposed increases in minimum flow from 4.6 cubic meters per second (the existing minimum flow) to 22.6 cubic meters per second (the increased minimum flow). Simulations included assessing the impact of (1) increased minimum flows and (2) increased minimum flows with increased initial water-surface elevation of 1.5 meters in Bull Shoals Lake on outflow temperatures and dissolved-oxygen concentrations.The increased minimum flow simulation (without
increasing initial water-surface elevation) increased the water temperature and dissolved-oxygen concentration
in the outflow. Conversely, the increased minimum
flow and increased initial water-surface elevation (1.5 meters) simulation decreased outflow water temperature
and dissolved-oxygen concentration through time. However, results from both scenarios for water temperature and dissolved-oxygen concentration were within the boundaries of the error between measured and simulated water column profile values.