Reclamation Information Sharing Environment (RISE)

The Navajo-Gallup Water Supply Project will convey water from the San Juan River to the Navajo Nation, the Jicarilla Apache Nation, and the City of Gallup, New Mexico. One aspect of the NGWSP is the design and construction of the San Juan Lateral (SJL) water treatment plant (WTP). The SJL WTP will treat water from the San Juan River to meet Safe Drinking Water Act (SDWA) requirements. This project is intended to provide information to determine how monsoon events affect the influent water quality to the SJL WTP. Parameters that exceeded SDWA limitations during storm events include several total metals and total dissolved solids. No correlation was observed between discharge flow rate and turbidity or suspended sediment concentration (SSC) in the San Juan River near the proposed intake. Turbidity correlated to several total metals. Evidence suggests that when SSC was high during Storm Event 3, the turbidimeter incorrectly recorded decreasing turbidity. Without Storm Event 3 data, turbidity correlates to SSC. When the turbidimeter is recording values lower than its maximum recording limit, it may be used to predict SSC and some total metals. Dissolved metals did not correlate to turbidity, SSC, discharge, or total metals.