River corridor systems in snow-dominated, mountainous regions often express complex biogeochemistry and river water nutrient indicators as a function of hydrologic exchange variability and snowmelt conditions. Watershed ecological control points (ECPs) (e.g. hyporheic zones, riparian hollows, stream bed bedrock fractures) are important for solute and nutrient processing at small scales, yet can have major impacts on large scale watershed exports. A major motivating factor for our work is a decadal time series which display declines in inorganic nitrogen over time as well as down the watershed network, indicating the importance of the passive versus active transient nature of these ECPs[1]. We investigate a loose-coupling strategy for hyporheic systems that allows river gross primary productivity (GPP), hillslope runoff, and bedrock contributions to augment hyporheic zone function. We apply this model to the hyporheic zone along the East River, Colorado [2]. Across the hyporheic zone and floodplain, we measured surface and subsurface gases, geochemistry, isotopes, and used this data to constrain our model in the presence of transient hydrological flow conditions. A Bayesian approach was used for the river model that allows GPP, respiration, and diffusion parameters to vary with season, constrained by radiation, barometric pressure, water depth, temperature, pH, DIC, and atmospheric CO₂. These river simulations were used as boundary conditions to test the dynamic nature of the hyporheic zone in response to projected future temperature and atmospheric CO₂ representing carbon emission futures, and to compare future and current hyporheic zone processingThe reliance of active versus passive ECPs on the timing of meltwater infiltration, including the possibility of a longer vernal window under future climate change indicates the importance of ECPs as controls of river-based indicators of river corridor hydrobiogeochemical function.