Flow dynamics and connectivity of meandering streams and shallow aquifers: an observational study in northern New Mexico

Both the hydrologic response and the fate and transport of solutes at the watersheds scale are strongly influenced by stream-aquifer connectivity and its dynamic nature. The bidirectional feedback between these two systems changes over several spatio-temporal scales, requiring a complex, multi-variable observational network that captures the dominant processes taking place and the response to changes in hydrologic forcing. With this in mind and to better understand the dynamics of these systems and the effects that intra-annual weather variability has on physical and chemical processes, a monitoring network was installed at a meander bend of the East Fork of the Jemez River in the Valles Caldera National Preserve, a snow-dominated watershed in northern New Mexico. This work summarizes a year of observations of the temporal and spatial variability of the groundwater-surface water interactions with the aid of spatio-temporal patterns of water level, temperature, and electrical conductivity measured in the meander bend and vertical fluxes estimated with piezometers, subsurface thermal records, and distributed temperature sensing in the channel. A three-dimensional model is used to consolidate the data collected and draw general conclusions.