Application of a lake-watershed model for the determination of water balance

A lumped-parameter, lake-watershed response model has been developed for the Wabamun Lake system and used to assess the role of groundwater in the water balance of the lake. Wabamun Lake, located in central Alberta, Canada, has a surface area of 78 km2. The surrounding watershed has an area of 263 km2 and is covered by a thin layer (0–15 m) of glacial sediments, which in turn overlie bedrock deposits of sandstone, siltstone, shale and coal. Good agreement has been achieved between the monthly observed and the monthly predicted lake stages for a 26 yr record, with a maximum difference of less than 0.25 m. In addition, the simulation of lake chemistry, including specific conductance, Cl− and K+, is in good agreement with the observed data. On the basis on the simulations, the main hydrologic components contributing water to Wabamun Lake are direct precipitation (43.1–59.8%) and surface-water inflow (36.8–48.3%). Outflow from the lake occurs primarily through evaporation (46.5–57.5%) and the groundwater system (35.0–43.5%). Groundwater discharging to Wabamun Lake (1.3–8.6%) and surface water draining from the lake (0.0–18.5%) are minor components in the water balance of Wabamun Lake.