Assessment of Eutrophication Control Programs Using an Ecological Model for a Dimictic Lake

An ecological model of Lake Yunoko, a dimictic lake, was developed to assess various programs for eutrophication control. A multi-component dynamic model for nutrients in the bottom sediment-water system was incorporated into the model, a one-dimensional water temperature-water quality-ecological model. Good agreement between the model calculations and observed nutrients, chlorophyll-a, and dissolved oxygen concentrations in the water and nutrient concentrations in the bottom sediment was noted. The agreement between the model calculations and the measured nutrient flux from bottom sediment during the summer stagnation period was good. The effectiveness of sediment dredging, artificial circulation, and reduction of external phosphorus loading as eutrophication control programs on chlorophyll-a, PO₄₋P, and dissolved oxygen concentration in the water was assessed using a calibrated model.