The Watershed Analysis Risk Management Framework (WARMF) was applied to calculate the total maximum daily load of total phosphorus discharged to a reservoir without violating the water quality criteria of 20<space>μg/l of chlorophyll-a (algae). In addition to a hydroelectric plant at the dam, the reservoir has a thermal power plant on the shore. To simulate the impact of the thermal power plant, WARMF withdraws 113 cms of cooling water from the lake bottom, adds heat to it, and discharges the thermal effluent to the reservoir surface. The circulating water brings the hypolimnion water, which is typically rich in nutrients but low in algae, to the epilimnion. The surface water is enriched in phosphorus but diluted with respect to algae concentration. For the example case, the dilutional effect on algae was found to be more significant than the stimulatory effect of phosphorus. As a result, the total maximum daily load of phosphorus was higher with a thermal power plant than without. Policy makers can learn, through this type of scientific analysis, about the impacts of a thermal power plant and make rational decisions about phosphorus TMDL.