Summary

EPA is issuing a notice of proposed action under the Clean Water Act. EPA is proposing to issue a National Pollutant Discharge Elimination System (NPDES) permit renewal (No. NN0030345) to Navajo Engineering and Construction Authority (“NECA”) for the discharge of flushing, hydrostatic testing and disinfection water from the Navajo Nation Municipal Pipeline Project (“NNMPP”). The NNMPP involves the construction and installation of twenty-nine (29) miles of 24-inch diameter polyvinylchloride pipeline, pumping stations, and ancillary facilities beginning from Farmington, New Mexico, to Shiprock, New Mexico, in order to deliver potable water to the Navajo Nation.

Upon completion of pipeline installation, NECA proposes to perform flushing and hydrostatic testing/disinfection of new facilities and parts in the NNMPP prior to placing them into service. Approximately 3.5 million gallons of potable water provided by the City of Farmington and the Navajo Tribal Utility Authority’s storage tank will be used during the flushing phase and will be discharged to the head gate of the Hogback Irrigation Canal (herein referred to as Outfall 001.) NECA will next perform hydrostatic testing and disinfection on the pipeline in sections, using approximately 3.8 million gallons of potable water and discharging to the Yellowman Lateral of the Hogback Irrigation Canal (herein referred to as Outfall 002.) The discharge flow rates are 3,525 gallons per minute and 500 gallons per minute at Outfalls 001 and 002, respectively. The Hogback Irrigation Canal is approximately 17 miles long and is a tributary to the San Juan River. The irrigation canal is not utilized from November to beginning of April. Any sampling and monitoring under the proposed permit will be performed at both Outfalls 001 and 002 prior to entry into the receiving waters.

***Please bring the foregoing notice to the attention of all persons who would be interested in this matter. ***