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Water Supply of the Eastern Plateau Planning Area - Effluent and Contamination Sites

Surface water, groundwater and effluent are important water supplies for municipal, industrial and agricultural uses in the Eastern Plateau Planning Area. Effluent and contamination sites are discussed here.


More than 36,500 acre-feet of effluent is  estimated to be generated annually in the planning area (Table 2.1-9). The communities of Flagstaff, Flagstaff Ranch, Holbrook and Page use effluent for golf course and landscape irrigation. In 2006 and 2007 over 2,300 acre-feet of effluent was used in the Flagstaff area.  Reclaimed water is produced by both of the city’s wastewater treatment plants.  A total of 10 schools, eight parks, two cemeteries, three golf courses and a playing field at Northern Arizona University receive treated effluent. In addition, a large industrial user, SCA Tissues, which had been Flagstaff’s second largest potable water user, converted to 100% reclaimed water use in 2005, resulting in a potable water savings of more than 300 AFA (SCA, 2007). Flagstaff also has a reclaimed water hauling program that makes Class A+ and Class B reclaimed water available for non-potable uses at four sites located throughout the city (City of Flagstaff, 2008). A proposal to use Flagstaff effluent to make snow at the Snowbowl ski area has resulted in a multi-year court battle between a coalition of tribes and environmentalists and the owners of Snowbowl and the Forest Service that remains unresolved.

Other communities in the planning area discharge effluent to fields for agricultural irrigation or to support wetlands (see Table 2.1-9). The Town of Eagar provides treated wastewater at no cost to local hay farmers (Town of Eagar, 2005) and all Snowflake’s effluent is applied to a local rancher’s hay field.

Approximately 11,900 AFA of industrial wastewater is generated by the Catalyst Paper Mill (formerly Abitibi) near Heber and discharged to a dry lake where it is used to irrigate pasture. Effluent generation location, volumes and disposal method are shown in Table 2.1-9.

Click to view Figure 2.0-17

Contamination Sites

Environmental contamination sites may impact the use of some water supplies.  An inventory of Department of Defense (DOD), Resource Conservation and Recovery Act (RCRA), Superfund (Environmental Protection Agency designated sites), Water Quality Assurance Revolving Fund (state designated WQARF sites), Voluntary Remediation Program (VRP), Uranium Mill Tailings Remedial Action (UMTRA) and Leaking Underground Storage Tank (LUST) sites was conducted for the planning area.  Of these various contamination sites, VRP, UMTRA and LUST sites are found in the planning area.  Table 2.0-7 lists the contaminant and affected media at UMTRA and VRP sites.  The location of all contamination sites in the planning area is shown on Figure 2.0-17.

There are three active VRP sites with soil and groundwater contamination. PCE, TCE and fuel oil are found in groundwater at the Arizona Public Service (APS) Cholla Power Plant site. At Winslow, soil contamination is found at the La Posada Hotel site, located adjacent to a railroad station and equipment yard. The Georgia-Pacific Corporation site in Flagstaff is also a railroad site; the particular contaminants at this site are not known. The VRP is a state administered and funded voluntary cleanup program.  Any site that has soil and/or groundwater contamination, provided that the site is not subject to an enforcement action by another program, is eligible to participate.  To encourage participation, ADEQ provides an expedited process and a single point of contact for projects that involve more than one regulatory program (Environmental Law Institute, 2002).

Two UMTRA sites are located on the Navajo Reservation at Tuba City and Monument Valley. The former Monument Valley mill and tailings site covers approximately 83 acres.  Surface remediation was completed in 1994.  A nitrate plume with concentrations ranging from 44 to 1,030 mg/L extends approximately 4,500 feet north of the site. Uranium concentrations exceed the UMTRA standard of 0.044 mg/L at a site in the alluvial aquifer and in a well completed in the De Chelly formation that was contaminated from the overlying alluvium. Approximately 540 million gallons of groundwater in the alluvial aquifer are contaminated. The Department of Energy (DOE) will conduct pilot studies and continue with remediation, monitoring and enforcement strategies until contaminant concentrations have been reduced to acceptable levels. (DOE, 2007)

Table 2.0-7 Contamination Sites in the Eastern Plateau Planning Area

Uranium Mill Tailings Remedial Action (UMTRA) Sites
Tuba City Disposal Site Groundwater - Molybdenum, Nitrate, Selenium, Uranium and Sulfate
Monument Valley Processing Site Groundwater - Uranium, Ammonium, Nitrate and Sulfate
Voluntary Remediation Program (VRP) Sites
APS Cholla Power Plant Groundwater - Tetrachloroethylene (PCE), Trichloroethylene (TCE) and Fuel oil              Soil - Fuel Oil
La Posada Hotel Soil - Diesel fuel and Total petroleum hydrocarbons (TPH)
Georgia-Pacific Corp. Flagstaff Facility Soil and Groundwater - Unknown

The Tuba City site, located five miles east of Tuba City is a former uranium mill that created radioactive mill tailings that were conveyed to evaporation ponds at the site. Surface  remediation was completed in 1990. Seepage from the evaporation ponds contaminated groundwater in the N-aquifer. The original volume of contaminated groundwater was between 1.5 and 3 billion gallons.  Contaminants include molybdenum, nitrate, selenium, uranium and sulfate.  Active groundwater remediation is underway at the site using extraction wells and removal of contaminants (DOE, 2008b).

Widespread mining and milling of uranium ore on the Navajo Reservation beginning in the 1940s also resulted in a large number of abandoned uranium mines (AUMs) and dispersion of radiation and heavy metal contamination in soil and water.  In 1993, the Navajo Nation brought concerns about health risks associated with these mining activities to the EPA, DOE and Bureau of Indian Affairs (BIA).

In response, EPA initiated a study through the Superfund Program to assess human exposure to radiation and heavy metals from each known AUM on the Navajo Nation. By August 2007, EPA completed a study identifying 520 AUMs. In June 2008, the EPA, in partnership with DOE, BIA, the Indian Health Service and the Nuclear Regulatory Commission, finalized a five-year plan for cleaning up the abandoned uranium mining sites on the Navajo Nation. (EPA, 2008)

There are 260 active LUST sites in the planning area.  Fifty-seven sites are located at Flagstaff, 53 at Winslow, 37 at Holbrook, 29 at Show Low/Pinetop/Lakeside, 28 at Springerville/Eagar, 18 at Page, 11 at Heber and eight at Snowflake.


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