Hydrogeologic and geochemical characterization and evaluation of two arroyos for managed aquifer recharge by surface infiltration in the Pojoaque River Basin Completed

In order to provide long-term storage of diverted surface water from the Rio Grande as part of the Aamodt water rights settlement, managed aquifer recharge by surface infiltration in Pojoaque River Basin arroyos was proposed as an option. The initial hydrogeologic and geochemical characterization of two arroyos located within the Pojoaque River Basin was performed in 2014 and 2015 in cooperation with the Bureau of Reclamation to evaluate the potential suitability of these two arroyos as sites for managed aquifer recharge through surface infiltration. There are several favorable characteristics of the two arroyos, including the channel capacity for managed flows, evidence of local recharge and a geochemical and mineral environment that suggests that storing water diverted from the Rio Grande is not likely to lead to high concentrations of metals from the local geology. However, the low storage-potential of the channel deposits and shallow bedrock, along with the need for significant infrastructure to retain applied water at the site, present challenges to using the arroyos for long-term water storage.