Rio Grande High-Resolution Riparian Groundwater Models

SSP&A developed a suite of groundwater models for the shallow riparian groundwater environment along the Rio Grande to support analysis of restoration options and river conveyance efficiency.  This project was conducted to support the Endangered Species Act Collaborative Program for the Middle Rio Grande, with goals related to fisheries, wetlands and interstate stream compact obligations.  This multiple year project was completed in January 2008, with the development of eight fine-mesh, three-dimensional groundwater models from Cochiti Dam to Elephant Butte Reservoir.  The shallow riparian groundwater models represent physical processes relevant to assessing shallow groundwater conditions and exchanges between surface water and shallow groundwater within the river floodplain.  Using input from existing regional surface- and groundwater models, the models developed in this study can be used to analyze transient interactions between flow conditions in the river (and drains) and the shallow groundwater under various conditions that may occur in future years.  Modeled interactions include seepage from the river, interception of shallow groundwater by drains, recharge to shallow groundwater from flooded overbank areas, and water depletions due to open water evaporation and riparian evapotranspiration.  The models can be structured to provide surface water-groundwater interactions with time steps of hours or days, to track responses to flood waves and recession.