Grant: Discovery Grants Program - Individual

In Northeastern Ontario, communities rely on regional-scale Precambrian shield watersheds for many ecosystem services including water provisioning, flood mitigation, and aquatic habitat sustainability. These `working watersheds' are, however, experiencing impacts from a wide range of stresses including climate and land use change. The study of the cycling of water through our watersheds is critically important to improving our ability to predict the impact of human activities on these freshwater resources. While computer models are primary tools that help predict future impacts on water resources they come with large uncertainties. Field-based water cycling studies in which we trace the movement of water can generate important insights into how water is stored and released to our waterways, which in turn can improve these computer models. A new approach using the seasonal variation in isotopes of oxygen and hydrogen of water to estimate the proportion of streamflow moving quickly versus slowly from land to water (young water fraction) now offers better accuracy for larger watersheds with complex landscapes. This, combined with technology that has reduced the cost and improved accessibility of laboratory analysis means we can generate new evidence of important hydrological processes at scales directly relevant to watershed management and decision making. The new knowledge we generate by tracing water is strongly complimentary to the study of pollution in the landscape, including Chloride from road salt application. With recent reporting of increasing Chloride concentrations in lakes and groundwater at many locations across the province of Ontario, we will combine tracing water movement with study of Chloride mobilization in tributaries along the northshore of Lake Nipissing. Lake Nipissing and its 13,000 km2 watershed are part of an important headwater tributary that flows into Georgian Bay, providing drinking water to local municipalities and First Nation communities, home to a First Nation's fishery and a premier recreational angling destination. Findings from this research program will support both regional interests in the longterm sustainability of Lake Nipissing's aquatic habitat and build new insight into regional-scale hydrology in mixed landuse Precambrian Shield catchments.