USE OF A RESERVOIR WATER-QUALITY MODEL TO SIMULATE GLOBAL CLIMATE CHANGE EFFECTS ON FISH HABITAT

A case study was conducted on the potential impacts of climate change on fish habitat in a southeastern reservoir. A reservoir water quality model and one year of baseline meteorologic, hydrologic, and inflow w ater quality input were used to simulate current reservoir water quali ty. Total adult striped bass habitat, defined by specific quantitative temperature and dissolved oxygen criteria, was simulated. Daily reser voir volumes with optimal, suboptimal, and unsuitable temperature and DO were predicted for the year. Output from recent runs of atmospheric general circulation models (GCMs), in which atmospheric carbon dioxid e concentrations have been doubled, was then used to adjust the baseli ne inputs to the water quality model. New sets of input data were crea ted for two grid cells for each of three GCMs. All six climate scenari os are predicted to cause overall declines in the available summer str iped bass habitat, mostly due to lake water temperatures exceeding str iped bass tolerance levels. These predictions are believed to result f rom the consensus among GCM scenarios that air temperatures and humidi ty will rise, and the sensitivity of the reservoir model to these para meters. The reservoir model was found to be a promising tool for exami ning potential climate-change impacts. Some of the assumptions require d to apply GCM output to the reservoir model, however, illustrate the problems in using large-scale grid-cell output to assess small-scale i mpacts.