Quantifying the spatiotemporal dynamics of recharge in a composite Great Lakes watershed using a high-resolution hydrology model and multi-source data

Abstract

Understanding the timing, location and rates of recharge is important for sustainable groundwater management and effective management of groundwater-dependent ecosystems. This paper explores the spatiotemporal distributions of large- and small-recharge events in a composite watershed in the Great Lakes region and examines the impacts of climate, land use/land cover, soils, and topography on simulated recharge. Novel aspects of the work include recharge estimation using an integrated hydrologic model and constraining the model using field observations of baseflows in both perennial and intermittent streams in the region as well as the United States Geological Survey (USGS) streamflows, groundwater heads, and satellite-based evapotranspiration (ET) products. Simulated high (low) recharge values were associated with high (low) elevations and regions of low (high) ET. The temporal dynamics of recharge are dominated by interannual climate variations, but are also affected by land cover types and soil types. Recharge occurred year-round in agricultural lands but intermittently in forested lands with both recharge and discharge occurring at different times within the same grid cell. Major recharge pulses were associated with spring snowmelt and also occurred in summer and fall and sometimes in late fall but there was considerable variability from year to year depending on the dominant land use and climate. Our approach based on the use of an integrated hydrologic model combined with multi-source data can be used in larger areas and is suitable for studying climate change impacts on groundwater resources.