Nye County - Town of Gabbs Fluoride (& Arsenic) Mitigation PER
BACKGROUND
The Town of Gabbs is located in northwest Nye County, 30 miles south of the intersection of Highways 50 and 361. It is believed that the Gabbs Valley was named after William More Gabb, a paleontologist who was a member of a survey team back in the 1860s.
In the late 1920s, brucite (a magnesium bearing mineral) was discovered in the valley. Brucite grew slowly then boomed with the onset of World War II and the need for magnesium in the production of defense weaponry. The ore was transported to the Basic Magnesium, Inc. (BMI) plant in the town of Henderson south of Las Vegas. By the end of 1942, hundreds of workers and their families lived in new town sites named North Gabbs and South Gabbs. The Korean War and the opening of a new BMI plant in 1951 spurred the town's growth. Gabbs became the only city in Nye County on March 29, 1955. At that time, the area mines were still operating at full capacity and were the life-blood of the community.
The city fared well for many years and at its peak may have reached 1,000 residents. According to the 1970 U.S. Census, the population was 874. Since then, mining operations have been severely curtailed, and as of the 2000 census, it was the smallest city in Nevada having a population of 318. Gabbs' tax base could no longer sustain a municipal government and, for the first time in over 100 years, the state legislature disincorporated a municipality. On May 8, 2001, the city was unincorporated and once again became the Town of Gabbs.
 The Gabbs water system has one production well (Well No. 1) and one 500,000-gallon storage tank. Water is chlorinated at Well No. 1. The emergency well (Well No. 8) cannot be used as a back-up well without treatment due to high fluoride levels.
Water levels in Well No. 1 have been declining at an approximate rate of 3 feet per year since 1989. In that time, fluoride levels have increased and now exceed the State's Maximum Contaminant Level of 2.0 milligrams per Liter (mg/L also referred to as parts per million, ppm). Fluoride levels in Well No. 1 are currently 2.4 mg/L. Fluoride levels in Well No. 8 exceed 8 mg/L. The system is in violation of the state drinking water standard for fluoride and is currently on quarterly monitoring for arsenic. Nye County Public Works is responsible for the operation of the water and waste water facilities in Gabbs.
Nye County applied for a grant under the AB-198 program to assist with the PER for fluoride mitigation and distribution system improvements project for the Town of Gabba. The grant was originally approved by the Board for Financing Water Projects (Board) on March 14, 2007, for an amount not exceed $25,925 (85% of the eligible project costs estimated to be $30,500).
A PER (conforming to the requirements of the U.S. Department of Agriculture, Rural Utilities Service Bulletin 1780-2 - Preliminary Engineering Report - Water Facilities) for the Gabbs water system was completed in April 2008. The water system facilities were evaluated and generally found to be in good condition. The water distribution model developed for the system and calibrated with water pressure measurements taken by town maintenance personnel gives a good representation of the system.
The PER considered both treatment and non-treatment alternatives. Given the construction costs and increased operation and maintenance costs of treatment, the more favorable alternative is the drilling and construction of a new municipal production well. During the course of the PER, two sites were identified for test pumping and water sample analyses. These sites included an existing stock well called the "Holly Well" located in Lodi Valley approximately six miles northeast of the town and a domestic well located at the airport. Permission to access the "Holly Well" was denied by the rancher that owns the well. It is of note, however, that a sample taken from this well in December 2006 and analyzed at the Nevada State Health Lab showed an arsenic concentration of 9.0 micrograms per Liter (µg/L also referred to as parts per billion, ppb), below the current standard of 10 µg/L, and a fluoride concentration of 0.20 mg/L which is well below the standard of 2.0 mg/L. In December 2007, Carson Pump Company mobilized to the airport site to test pump the 6-inch, cased domestic well but could not produce water to obtain a sample.
The proposed capital improvement project to mitigate the fluoride issue includes a new, primary well and appurtenances on property owned by Nye County. Well No. 1 would then serve as a back-up or emergency well to the system. The estimated total cost of the new well, pump station, transmission line, and appurtenances is $998,664. Operating and maintenance costs should be similar to those paid for the current system. The Town of Gabbs has a wellhead protection plan created with the assistance of Nevada Rural Water and approved in December 2005. If a suitable location for a new well is found, a contaminate source inventory survey within 3,000 feet of the proposed well will be conducted and provided to the Bureau of Water Pollution Control, Groundwater Protection Branch for endorsement and subsequent inclusion in the Gabbs' Wellhead Protection Plan.
 Map of the Gabbs area & exploratory drilling locations.
Click Here or on image to the left to Expand View
The County and its engineering firm, Day Engineering, recognize that it is critical to ascertain production capabilities and associated water quality under stressed conditions to provide a more accurate evaluation of the aquifer characteristics. They reviewed available area well logs on file at the State Engineer's office and concluded that exploratory drilling in the alluvium and away from the eastern hills would be the most favorable location. The goal of this exploratory drilling is to determine both available water quantity and water quality. The Phase II project to this PER includes exploratory drilling and construction of a test well at the airport. Should that location not show favorable results, a second exploratory well would be drilled and constructed at the golf course for the purpose of both water quantity and quality testing.
The PER included additional findings and recommendations for improvements to the water system. These recommendations include: a transducer to measure the water level in Well No. 1; a surge anticipator valve at Well No. 1; functioning meters for all service connections; and the replacement of approximately 500 feet of 2-inch water main in north Gabbs to improve fire flow. It was noted that water use in Gabbs appears to be higher than in other rural communities that have similar amenities and vegetation.
Nye County applied for a PER Phase II grant under the AB-198 program to assist with the costs of drilling one exploratory well at the Gabbs airport. The grant was approved by the Board on June 19, 2008, for an amount not exceed $63,920 (85% of the eligible project costs estimated to be $75,200).
In December 2008, an exploratory well was drilled at the Gabbs airport to a depth of approximately 500 feet, and a monitoring well was constructed of PVC materials. While water quantity met expectations, the water quality did not meet the MCLs for either arsenic or fluoride. Nye County once again pursued permission to sample the Holly Well in Lodi Valley and was granted permission to do so in January 2009. The water quality results met the drinking water MCLs for both arsenic and fluoride. Nye County subsequently approved project funding to drill a second exploratory well; this time in Lodi Valley approximately 1 1/2 miles from the Town's Well #1. Results of that exploratory drilling should be available shortly.
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