Acid Precipitation Model for Seepage Lakes

Abstract

The Trickle‐Down model has been developed and applied to Vandercook Lake, Wisconsin, for an acidic deposition assessment. Three years of field data were simulated. Field data of lake stage and groundwater level at the nearshore piezometer were used for hydrological model calibration. Field alkalinity and pH data were used for alkalinity/pH model calibration. Hydrological budget calculations showed that almost all of the water in the lake came from precipitation falling directly on its surface. Alkalinity budget calculations indicated that 76% of the alkalinity produced came from internal processes, and the remainder of the alkalinity (24%) was supplied from groundwater inputs. Model results were within one standard deviation of field data for alkalinity at all times except the winter period of 1981–1982. Simulations of a doubling of the acid deposition to Vandercook Lake indicate that an acidification of the lake would occur over a 5–20 yr period.