Geochemical analysis and modeling for an artificial aquifer recharge study in the shallow zone squifer near Pojoaque, New Mexico.

An artificial aquifer recharge project is currently being evaluated as a component of the Pojoaque Basin Regional Water System as part of the Aamodt Litigation Settlement Act. The purpose of the project is for aquifer storage, with later retrieval as drinking water. The total diversion of San Juan Chama Project Water (SJCPW) for this project is approximately 4,000 acre-feet per year. It should be noted that some of the SJCPW would be treated and put directly into the drinking water system. The goal of this project is to extract the SJCPW from the Rio Grande and pump it into two arroyos, the Arroyo Jocona and an unnamed arroyo. The hope is that the water will reach the shallow aquifer via infiltration. The United States Geological Survey (USGS) performed a geophysical study of the two above-mentioned arroyos near Pojoaque, New Mexico to determine the lithology if SJCPW will infiltrate through the vadose zone and into the shallow aquifer system. The USGS also drilled four borings and completed monitoring wells in two of the borings. The wells were used to collect water levels and water quality samples. After performing analysis of the groundwater, using both an inductively couple plasma (ICP) and ion chromatography (IC) instruments, and analysis of the sediments using acid digestion and a batch extraction, it was determined that several analytes exceed the United States Environmental Protection Agency Drinking Water Standards. These analytes include aluminum, beryllium, fluoride, iron, and arsenic. All of these analytes are found at concentrations would most likely be able to be treated using standard modern water treatment techniques