Groundwater-lake interactions: II. Nearshore seepage patterns and the contribution of ground water to lakes in central Alberta

Abstract

Seepage flux was measured with seepage meters placed along transects from the lake shore to 30–110m offshore in 10 lakes in central Alberta during May–August 1986. In the study area, the predominant surficial deposit is glacial till which is underlain by sedimentary bedrock. Seepage flux into the lakes ranged from 3 × 10 −10 to 2 × 10 −7 ms −1. Seepage out of the lakes was recorded at only one of 92 seepage meter sites. At one lake, seepage was measured fortnightly along transects at two locations, from May to August 1986; seepage patterns were consistent throughout that period. In the nearshore region of six of 10 lakes, seepage flux to the lakes decreased with distance from shore. Deviations from that pattern were probably a result of: (1) spatial variability of seepage flux within a small area of lakebed; (2) intertill sand and gravel lenses near the lake; (3) preglacial bedrock channels of sand and gravel underlying some of the lakes. Ground water was the major source of water (49% of total inflow) to one lake; at the other lakes, ground water was a relatively small component (10%) of total inflow.