Lac St. Cyr was one of the first water bodies in Alberta to receive river water diversions. Since the 1950’s this lake has supplied water to the town of St. Paul. In 1978 Lac St. Cyr began receiving water diversions from the North Saskatchewan River during the winter months to re‐establish historic lake levels.
The lake was modeled from 1983‐1986, 1991 and 1995, using an empirical eutrophication model called BATHTUB, which produces steady‐state nutrient calculations. The results obtained for 1995 have been set as the standard calibration levels for each subsequent analysis.
The water quality of the North Saskatchewan River improved over this time, resulting in the improvement of the lake’s water quality. This study shows that Lac St. Cyr has reached a steady state with the current nutrient levels reflecting that of the river.