Use of water isotopes and chemistry to infer the type and degree of exchange between groundwater and lakes in an esker complex of northeastern Ontario, Canada

Abstract. While interactions between groundwater and lake-water influence water chemistry, balance, aquatic organisms, biochemical cycles contamination levels, they remain a poorly studied component of lake hydrology. Identifying the controls at landscape level classifying lakes into categories based on their degree interaction with can provide insights lake's sensitivity vulnerability to environmental stressors. Such information also baseline conditions for comparison future changes that are important management conservation. To this end, chemistry isotopic composition were investigated in set 50 boreal located different elevations an esker system near Timmins, Ontario. Analyses focused stable ratios hydrogen oxygen specific conductance as indicators position respect groundwater. Both distinguished higher-elevation groundwater-recharge from lower-elevation groundwater-discharge lakes. Groundwater-recharge high-elevation characterized by enriched values low conductance. In contrast, isotopically depleted had higher occurred lower elevations. An intermediate group was defined (termed seepage lakes) water-chemistry characteristics compared recharge discharge Differences geochemistry field campaigns revealed upland showed evidence evaporative drawdown, indicating short-term climate, whereas little variation seasonal samples consequently would likely be affected only hydroclimatological greater duration magnitude.