Interpreting high-frequency sensor data to quantify spatial and temporal variability in the source and transport of water and solutes at the catchment scale

Abstract:

In light of past, present, and future pressures placed on freshwater resources for both anthropogenic and natural uses, there is growing recognition that there is an urgent need to think of and manage groundwater and surface water as a single resource. Quantifying this resource requires a watershed-scale perspective. The myriad of hydrologic and biogeochemical processes taking place in watersheds occurring at different spatial and temporal scales are integrated and reflected in the quantity and quality of water in streams and rivers. Collection of high-frequency water quality data with sensors has provided new opportunities to disentangle these processes and quantify sources, transport, and retention of water and solutes in the coupled groundwater-surface water system. Here we provide examples of how high-frequency water quality data have been used to quantify spatial variability in the importance of groundwater in sustaining streamflow in the Colorado River Basin and temporal variability in groundwater contributions of nitrate to surface waters, and retention of that nitrate, in the Chesapeake Bay watershed. Additionally, we suggest that high-frequency water quality data can be used to inform and improve interpretation of patterns in discrete water quality data.