Ten-Year Forecasts of Water Quality in Lake Michigan Using a Deterministic Eutrophication Model

摘要

A dynamic, deterministic lake eutrophication model was used to forecast changes in Lake Michigan water quality over a ten-year simulation period. Emphasis was placed on changes in epiliminon phytoplankton biomass and in whole-lake total phosphorus concentration in response to changes in input phosphorus loads and to variations in winter conditions. Constant-condition simulations corresponding to current, increased, and reduced loads and to mild, average, and severe winters were used to establish bounds for the projected changes in water quality. Monte Carlo-type simulations were used to estimate the variance associated with the projections. Given the assumptions and limitations inherent in the modeling process, water quality in Lake Michigan is projected to improve slightly (reduced concentrations of phytoplankton and total phosphorus) over the next ten years. Year-to-year variations are significant, however, and will depend on loading and winter conditions. The variation in the projected values associated with the assumed fluctuations in loads and winter conditions is approximately 20 percent. 25 references, 20 figures, 4 tables. (ERA citation 09:029294)