Lyon County Utilities - Crystal Clear Water System Arsenic Mitigation Project
BACKGROUND
The Crystal Clear Water System (CCWS) is located off US Highway 95A in Lyon County, approximately 6 miles east of Yerington. The CCWS was started in 1966 by Nick and Shirley Nadel and incorporated as a privately owned water system. Bill and Diane Brandt purchased CCWS several years ago. Ownership of the system transferred to Lyon County Utilities Department (LCUD) on June 1, 2006.
CCWS owned 3 wells: North Well, Middle Well and South Well. Currently, 2 of the wells are used for public consumption and potable use. The South Well is off-line and not in use. There is no treatment process. Water is pumped and stored in pressure tanks before being sent into the distribution system.
There are two water storage tanks (pressure tanks) and two pressure zones in the system. All of the wells are located in the lower pressure zone (Zone 1 - El Rancho Estates); along with the 12,000-gallon pressure tank that stores water from the two wells. Water is lifted from Zone 1 to Zone 2 (South View Estates) via an underground pressure tank. Zone 2 is supplied by the underground, 1,600-gallon booster pressure tank located near South View Estates. The system does not have enough capacity to protect against fires although some fire hydrants (some simply sitting in the ground but not connected to the system) can be seen in the subdivision.
The well facilities are poorly constructed and do not meet State standards. Water from the wells is generally of good quality; however, arsenic, a Primary Drinking Water constituent, exceeds the drinking water standard of 10 micrograms/Liter (µg/L) (also referred to as parts per billion [ppb]) in both wells. The concentration of arsenic in the water is 42 - 47 µg/L. In September 2006, the State Environmental Commission granted CCWS an exemption from the arsenic compliance requirement until January 23, 2009. The water has a relatively high silica content which interferes with some arsenic treatment technologies. The average concentration of fluoride in the production wells is 2.67 milligrams/Liter (mg/L) (also referred to as parts per million [ppm]) - above the secondary maximum contaminant level (MCL) of 2 mg/L. Due to excessive fluoride content, individual defluoridation units were installed in December 1980 with provisions that they would be maintained by CCWS. These units were never been maintained and were not being used.
The CCWS does not meet all storage requirements. The system is served by a 12,000-gallon pressure tank, which has been leaking. The existing distribution system is made up primarily of 6-inch pipe; however, little was known about the distribution system with respect to pipe material, location of valves, and general condition. Some customers complain about pressure problems, and there are numerous, existing undersized and dead end lines.
The booster pressure tank that serves Zone 2 is not in good condition. Shortly after the LCUD took possession of the system, there was a severe failure in the booster station where the inlet piping expanded under extreme pressure and separated from the pump. The booster station was severely damaged and required significant repairs.
Some initial preliminary planning and investigation of the system was completed for the CCWS by LCUD. LCUD conducted field work to gather information on the condition of system components. In order to apply for match funding from the USDA, a detailed PER including updated information on system condition, alternatives analysis, a project scope and cost estimate, and an environmental report was completed in May 2007 and is on file with the Division of Environmental Protection, Office of Financial Assistance (NDEP, OFA) and the Bureau of Safe Drinking Water (BSDW).
Installing and operating treatment for arsenic and fluoride at the well head for the small number of active connections was not a preferred alternative based on both initial construction and continued operation and maintenance costs. The residents and the utilities operations staff also rejected the idea of point-of-use reverse osmosis (POU-RO) units. Without 100% community buy-in, the POU-RO system is not a viable option. The POU-RO systems are a good choice for a very small water system with little or no growth potential; however, this area does have the potential for future growth.
The PER included an arsenic study of water throughout the Yerington area and found that wells located near the CCWS have arsenic levels exceeding the MCL. The wells studied were only in the valley and generally shallow. The possibility of finding a new source, free of arsenic and fluoride at greater depth, was not investigated.
Due to the proximity of the CCWS to the City of Yerington, consolidation of the systems appeared to be a viable, non-treatment alternative for the CCWS. Yerington has pilot tested centralized arsenic treatment for its water system and plans to have treatment installed by the required compliance date - currently January 2011. A transmission main from Yerington to CCWS would be approximately 6 miles long and would be located along Highway 95A. In addition to an arsenic and fluoride compliant water supply, the CCWS also had identified the need for appropriate water storage and replacement of the water mains and appurtenances.
PROJECT DESCRIPTION
Lyon County Utilities applied for a grant under the AB 198 program to assist with the arsenic mitigation and distribution system project. The grant was originally approved by the Board for Financing Water Projects on August 23, 2006, for an amount not exceed a total of $2,663,635 (approximately 68.1% of eligible project costs estimated to be $3,911,500). The scope of this project is to install a transmission line and booster pump from the City of Yerington to a new storage tank near the Crystal Clear subdivision. In addition, water mains, services, and other appurtenances within the Crystal Clear service area will be replaced.
The City of Yerington and Lyon County Utilities Department agreed to transfer ownership of this new pipeline and system components to the City after the project is complete. The inter-tie will give the City the opportunity to have a more efficient cost because the efficiency of utilization is spread over a wider population base. The Board advocates cooperation and planning between water purveyors so that the per customer cost of constructing infrastructure and the water rates that the customers are paying remain affordable.
PROJECT STATUS
The project was bid in October 2008 with the bid being awarded to Campbell Construction. A majority of the new water mains and services are complete within the subdivision. The new storage tank has been constructed and is now in the process of being coated. Campbell Construction will soon complete the transmission between the City of Yerington and the new tank at Crystal Clear. When the booster station and PRV are installed, the system will be ready for start-up. The planned project completion is July 2008.
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