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4.4 Central Nevada Test Area

The existing environmental conditions of the Central Nevada Test Area are described in this section.

The Environmental Restoration Program activities at the Central Nevada Test Area would not have the potential to impact waste management, transportation, socioeconomics, or occupational health and safety. Therefore, development of a detailed baseline for these issues is not warranted. A brief explanation as to why these issues are not described is as follows:

  • Waste ManagementNo waste management facilities exist at the Central Nevada Test Area. Any waste generated during the course of Environmental Restoration Program activities would be transported to either the NTS or a permitted hazardous waste facility.

  • TransportationNo public roads currently exist at the Central Nevada Test Area. Access to the site during Environmental Restoration Program activities would only generate a minor amount of traffic on local roads. Transportation of investigation-derived and remediation-generated waste is discussed in Section

  • SocioeconomicsNo new facilities will be located at the Central Nevada Test Area.

  • Occupational Health and SafetyAny environmental restoration activities occurring at the Central Nevada Test Area would be required to comply with applicable DOE orders and directives concerning occupational health and safety as described in Section 4.1.11 .

4.4.1 Land Use

The closest permanent habitation to the Central Nevada Test Area is the Hot Creek Ranch, located 16 km (10 mi) southwest of surface ground zero. The nearest population center is the town of Tonopah, located 97 km (60 mi) southwest of surface ground zero.

The Central Nevada Test Area is located in the north-central part of Hot Creek Valley, a remote desert area in south-central Nevada, 97 km (60 mi) northeast of Tonopah, in Nye County, Nevada, and 52 km (32 mi) northeast of Warm Springs, Nevada (Figure 4-57 ). A portion of this area is also within the Toiyabe National Forest. The Central Nevada Test Area was obtained by the Atomic Energy Commission for the purpose of developing potential alternative sites for nuclear testing activities. Several emplacement holes were drilled in anticipation of future events; however, Project Faultless was the only nuclear test conducted at the Central Nevada Test Area. The event was conducted on January 19, 1968, at a depth of 975 m (3,200 ft), and had a yield of approximately 1 megaton (DOE, 1994a). Public Land Orders and Withdrawals.

The Central Nevada Test Area consists of two non-contiguous areas that were withdrawn by Public Land Order 4338; 640 acres for the Project Faultless detonation, and Public Land Order 4748 (1,920 acres) for a total of 2,560 acres. (SAIC/DRI, 1991). Although surface is not controlled, subsurface access is restricted by the DOE. Land Use Designations.

Site-support activities, such as movable trailer modules for use as offices, dining facilities and dormitories, tanks, power lines, underground cables, and an airstrip existed only temporarily at the Central Nevada Test Area during preparation, testing, and demobilization. Demobilization activities began in 1973, when all facilities except the Base Camp, Control Point, Noname Hill, and the airstrip were removed. Numerous drillholes used for subsurface soil and groundwater sampling were plugged; however, four wells have been left open for hydrologic monitoring on the site (DRI, 1988). Aside from this long-term hydrologic monitoringsite, land use is confined to cattle grazing and recreation. Site-Support Activities.

Site-support at the Central Nevada Test Area is described in this section.

FACILITIESThere are no existing facilities at the Central Nevada Test Area.

SERVICESServices described at the Central Nevada Test Area are law enforcement and security, fire protection, and health care.

Law Enforcement and SecurityNo security is provided at the Central Nevada Test Area. Law enforcement is provided by the Nye County Sheriff’s Department.

Fire ProtectionFire protection for the Central Nevada Test Area is provided by the U.S. Bureau of Land Management.

Health CareNo health care facilities currently exist at the Central Nevada Test Area.

UTILITIESThe Central Nevada Test Area does not contain utility systems.

COMMUNICATIONSNo communication systems are currently located at the site. Airspace.

The Central Nevada Test Area is not located beneath any special-use airspace used for DOE or defense-related purposes.

4.4.2 Transportation

No public roads currently exist on the Central Nevada Test Area. Access to the site during environmental restoration activities would generate only a minor amount of traffic on local roads and the immediate regional highway (U.S. Highway 6), which are currently under-used. In 1993, U.S. Highway 6 near Warm Springs carried an average of 145 to 210 vehicles per day. This traffic volume is far below the two-way vehicle capacity of U.S. Highway 6 at this location, which is approximately 1,700 vehicles per hour.

Figure 4-57. Central Nevada Test Area and surrounding area

4.4.3 Socioeconomics

The majority of DOE/NV workers, including those assigned to projects at the Central Nevada Test Area, live in Clark or Nye counties (DOE, 1994b). An analysis of socioeconomic conditions in Clark and Nye counties is presented in Section 4.1.3 .

4.4.4 Geology and Soils

Physiography, geology, and soils are addressed in this section for the Central Nevada Test Area. Physiography.

The Hot Creek Valley is within the Basin and Range Physiographic Province. See Section for a description of this province. The valley is about 113 km (70 mi) long on its north-south axis and varies in width from 16 to 32 km (10 to 20 mi). The Project Faultless site is in the north-central portion of the valley (AEC, 1973b). The Hot Creek Range lies immediately to the west and rises to an elevation that is 1,219 m (4,000 ft) above the site. Geology.

The mountains immediately west of the site are composed of volcanic rocks interlayered with sedimentary units (Stewart and Carlson, 1978). The thick alluvial fill of Hot Creek Valley displays little evidence of the structural framework or stratigraphy of the valley; therefore, the primary source of subsurface geologic data is the several exploratory holes that were drilled in the area. The Project Faultless emplacement hole (UC-1) penetrated alluvium from the surface to a depth of 732 m (2,400 ft). The alluvium is underlain by tuffaceous sediments and zeolitized tuff from 732 to 998 m (2,400 to 3,275 ft), which includes the total depth of the hole. The geologic media at the shot point consisted of tuffaceous sediments and zeolitized nonwelded tuffs (DRI, 1988).

The Project Faultless test, detonated in the saturated zone, created a large cavity. The estimated radioactivity at one minute after shot time was 3 x 1013 Ci. The event resulted in numerous surface fractures up to 2,743 m (9,000 ft) in length, with vertical displacement up to 5 m (15 ft) and horizontal offset up to 1 m (3 ft). The explosion resulted in the formation of an irregularly-shapedsubsidence block of approximately 372 m² (4,000 ft²), bounded by local faults in the surface ground zero area (DRI, 1988).

Although Hot Creek Valley has historically been the site of significant mineral production, most deposits have been fully developed and mining activity is now limited to a few small operations. According to (Kleinhampl and Ziony, 1984), historic production has included antimony, barite, gold, lead, silver, turquoise, uranium, and zinc. Most of this production came from two mining districts, the Morey District from 1866 to 1953 and the Danville District from 1866 to 1950.

Because of the proximity of Hot Creek Valley to the largest producing oil fields in Nevada (in Railroad Valley), there has been limited interest in oil and gas exploration. According to (Garside et al. 1988) and (Hess and Davis, 1995), only two oil wells have been drilled in Hot Creek Valley. The Hot Creek Federal No. 24-13 well was drilled in 1981 to a total depth of 3,361 m (11,028 ft). Although this well exhibited numerous gas shows below a depth of 2,710 m (8,890 ft), no oil was found, and no production came from the well. The other well, Warm Springs Federal No. 10-14, was drilled in 1981 to a total depth of 2,798 m (9,180 ft) with no reported shows of either gas or oil. Soils.

Soils most likely encountered at the Central Nevada Test Area range from rock outcrops and stony-cobbly alluvial fans to fine-loamy, and sometimes calcareous, soils (Cox et al., 1977). These are also referred to as Xerollic Durargids, Xerollic Durarthids, and Typic Durargids.

4.4.5 Hydrology

This section contains the discussion of surface water and groundwater conditions at the Central Nevada Test Area. A discussion of wells in the vicinity is also presented in this section. Surface Hydrology.

The Central Nevada Test Area, located in Hot Creek Valley, is within the Great Basin hydrographic region. This region is characterized by the alluvium-covered topographically closed valleys and elongated north-south trending mountain ranges typical of the Basinand Range Physiographic Province. Hot Creek Valley is bordered by the Hot Creek Range on the west and the Pancake Range on the east. The topography of the region controls the surface water drainage (DOE/NV 1992), with the higher elevations receiving more precipitation than the lower elevations. Perennial surface waters are limited to low-discharge springs that travel a short distance before evaporating or infiltrating back into the ground (DOE, 1986). The Hot Creek Range hosts numerous springs that flow away from the site. The nearest spring to the site is 5 km (3 mi) away. No perennial streams cross the Central Nevada Test Area, and there are no permanent surface water bodies. Morey Canyon and South Canyon are prominent ephemeral streams that pass through the Central Nevada Test Area to Moore’s Station Wash, 2 km (1 mi) east of the site. Owing to the intermittent flows in these streams, there are no surface-water quality data from streams that cross the Central Nevada Test Area. Groundwater.

The hydrogeology of Hot Creek Valley is controlled in part by the basin-and-range topography. The valley is a long graben (an elongated depressed block of crust bounded by faults on its long sides) containing a sequence of Quaternary and Tertiary alluvial fill (up to 1,200 m [3,936 ft]) underlain by Tertiary volcanic rocks. The bounding ranges on either side of the valley contain Paleozoic carbonates overlain by Tertiary age volcanics (Thordarson, 1987). Boreholes close to the site penetrate approximately 610 m (2,001 ft) of alluvium underlain by tuffaceous sediments and volcanic rocks.

The watertable in Hot Creek Valley generally occurs within the alluvium, and groundwater flow is believed to follow the general direction of surface flow (Rush and Everett, 1966; Fiero, 1986). The depth to groundwater in wells drilled at the Central Nevada Test Area ranged from 66 to 168 m (215 to 551 ft) below land surface at the time of drilling in 1967. Recharge occurs in the higher mountain range to the west (Hot Creek Range), with ground water flowing toward the east-central part of the valley (Figure 4-58 ). Discharge is by evaporation in low portions of the valley (the area around Twin Springs Ranch), with a minor amount of subsurface flow out of Hot Creek Valley to Railroad Valley(Rush and Everett, 1966). Little information is available on water flow in the bedrock aquifers of the valley. Differences in hydraulic head, water chemistry, and temperature suggest that the alluvium and volcanics are distinct water-bearing zones (Dinwiddie and Schroder, 1971). Head values in the upper 340 m (1,115 ft) of the section indicate that groundwater movement is generally south to southeast. Head values measured in units 1,500 to 2,100 m (4,920 to 6,888 ft) below land surface reveal that the deep component of the flow system moves northeast and east to Railroad Valley. Evaluation of vertical head gradients indicates a potential for downward flow in the north end of the valley (in the immediate test area), while an upward potential for flow exists over the southern part of the valley. Dinwiddie and Schroder (1971) concluded that vertical movement is slow relative to lateral flow, based on the anisotropy of hydraulic properties.

The Project Faultless test occurred in the tuffaceous sediment section, but the resultant cavity extended into the overlying alluvium. The pre-event water-table level was predicted to be reached between the years of 1993 and 2018 (Thordarson, 1987), with recent measurements indicating the level is still depressed by about 50 m (164 ft), but rising at a rate of approximately 8 m/yr (25 ft/yr) (Chapman et al., 1994). Although radionuclide transport from the chimney was not expected until the pre-event water level was reached, logging in the post-shot hole at the site has revealed horizons of water outflow, which, if representative of conditions outside the chimney, suggests that transport could already be occurring (Chapman et al., 1994). The Long-Term Hydrologic Monitoring Program includes sampling of five wells and one spring in Hot Creek Valley. No contamination related to the Project Faultless test has been detected in samples from those wells.

Private wells in Hot Creek Valley are believed to be completed in the upper part of the alluvium section. They are used for domestic, farming, and stock-watering purposes. The perennial yield of Hot Creek Valley is estimated at 7 x 106 m3 (5,500 acre-feet) (Rush and Everett, 1966). Some springs in the area have elevated temperatures and chemical characteristics that indicate they could be discharge points for deeper, regional flow systems. The sparse data indicate that groundwater quality is generally good, although salinity increases in the natural discharge area near Twin Springs Ranch (Rush and Everett, 1966).

Figure 4-58. Hydrogeologic features of the Central Nevada Test Area

4.4.6 Biological Resources

The scientific names of plants and animals mentioned in this section are given in Section 2.0 of Appendix E, Biological Resources. The Central Nevada Test Area is at an elevation of about 1,861m (6,104 ft). This site and the rest of Hot Creek Valley has vegetation typical of the Great Basin region. The valley bottom is dominated by big sagebrush, with scattered rabbitbrush and Indian ricegrass. At the slightly higher elevations in the big sagebrush, with scattered rabbitbrush and Indian ricegrass. At the slightly higher elevations in the foothills surrounding the valley, sagebrush, pinyon pine, and juniper form an open woodland (EG&G/EM, 1993a). The most common plants found at the springs and wells in this valley and the surrounding mountains are sedges, rushes, and desert saltgrass. Disturbed sites in the valley are dominated by exotic weeds, such as halogeton, goosefoot, Russian thistle, and tansy mustard.

Animal species are probably similar to those found on the Tonopah Test Range. Mule deer are year-round inhabitants (BLM, 1993), and wild horses, pronghorn, and mourning dove are known to use springs in the area (EG&G/EM, 1993a).

No current federally threatened, endangered, or candidate plant or animal species are known to occur on the Central Nevada Test Area, although bald eagles and peregrine falcons may be rare migrants. The U.S. Fish and Wildlife Service published the latest list of candidate plants and animals on February 28, 1996 (61 FR 7596). Prior to this, 10 vertebrate species, 1 invertebrate species, and 5 plant species that were identified as potentially occurring at this site were classified as candidates (Mendoza, 1995b) and were addressed (Table 4-30 ). The updated Notice of Review has removed all of these species from candidate status. The western burrowing owl, 1 of over 20 state-protected birds, may occur at this site.

Five Category 2 candidate plant species may occur in the vicinity of the test area (Cooper, 1993; EG&G/EM, 1993a). None of these species was found within the test area during a survey in 1993 (EG&G/EM, 1993a); however, sanicle biscuitroot was found just south of the site. Sanicle biscuitroot is not endemic to this site and may be found throughout the southern half of Nevada, and in scattered populations in California (Blomquist, et al., 1995).

4.4.7 Air Quality and Climate

This section includes description of air quality conditions at the Central Nevada Test Area, including climatology, meteorology, and ambient air quality.

CLIMATOLOGY AND METEOROLOGY Meteorological measurements are not available at this site. However, based on climatological maps of temperature and precipitation (Ruffner, 1980), temperatures would be 1 to 2 °C (2 to 4 °F) cooler than those on the Tonopah Test Range Section 4.2.7 ). Mean annual precipitation is estimated to be about 20 cm (8 in.). Wind speed and direction characteristics are similar to those that occur on the Tonopah Test Range.

AMBIENT AIR QUALITYThe Central Nevada Test Area is located within Nevada Intrastate Air Quality Control Region. Ambient air quality has not been monitored for criteria pollutants at the Central Nevada Test Area. However, because of the lack of significant pollutant emission sources, the air quality is good. Air Quality Control Region 147 is designated unclassifiable/attainment for all criteria pollutants.

4.4.8 Noise

The acoustic environment of the Central Nevada Test Area and surrounding areas can be classified as uninhabited desert or small rural communities. Noise measurements have not been taken at the Central Nevada Test Area. The major sources of noise would be associated with prevailing meteorological conditions, such as wind. Traffic on U.S. Highway 6, which is 11 km (7 mi) to the southeast, would not have a significant acousticimpact at the Central Nevada Test Area. The only projects anticipated for the Central Nevada Test Area are Environmental Restoration Program projects that would not create loud noises nor would they be affected by loud noises.

4.4.9 Visual Resources

The landscape character of the Central Nevada Test Area is typical of the Great Basin. Regional topography consists of mountain ranges arranged in a north-south orientation, separated by broad valleys. Because this site is located at the east base of the Hot Creek Range, scenic quality has been designated Class B. U.S. Highway 6, 19 km (12 mi) to the southeast, is the closest public highway. It has an average daily traffic of about 200 vehicles. Therefore, the sensitivity level would be low.

4.4.10 Cultural Resources

Archaeological research in the Central Nevada Test Area, and particularly in Hot Creek Valley, has documented the presence of significant cultural resources. Archaeological sites ranging from the early prehistoric period to historic mining and ranching sites are known. These sites have been identified, located, and evaluated by a variety of cultural resources surveys and excavations. A large gap exists in the archaeological database as the research conducted for the Project Faultless project was never incorporated in the statewide inventory. A large collection of between 20,000 and 30,000 artifacts, field notes, photographs, and other records on file at the University of Nevada, Las Vegas, indicates there are over 100 sites within the Central Nevada Test Area that have never been properly recorded (Edwards and Johnson, 1994).

Small bands of Western Shoshone people lived in the project area vicinity. Villages were located at Hot Springs and Twin Springs, while family camps were situated along Hot Creek and Tybo Creek (Steward, 1938 [Figure 4-48 ]). These groups harvested pine nuts in the southern part of the Hot Creek and Kawich Ranges. They often joined Kawich Mountain people for antelope and rabbit drives in Hot Creek Valley and the Kawich Mountains (Steward, 1938).

The Central Nevada Test Area includes three withdrawn areas of land totaling approximately 2,560 acres (SAIC/DRI 1988). Environmental restoration activities in the region of ground zero of the Project Faultless event have included sampling wells and springs up to 40 km (25 mi) from ground zero. Anticipated Environmental Restoration Program activities will include construction of wells. Thus, an area of potential effect for environmental restoration activities was created, and an overview of all recorded cultural resources and cultural resource surveys was performed.

RECORDED CULTURAL RESOURCES-Twenty-six cultural resource reconnaissance projects have been conducted in the area of potential effect. These projects and other recording projects have yielded just over 100 sites. Among the prehistoric cultural resources are two rock art sites, called stations. One of them, is called Moore's Station in (McLane, 1993:28) because of its proximity to that site. The other site is located in a rock shelter on Palisade Mesa. Prehistoric sites range from as few as four artifacts to extensive concentrations of artifacts and features. An additional site includes three large hearths and abundant flakes, flake tools, and groundstone. Most of the prehistoric sites that have been recorded in the area are smaller sites. The larger, more complex sites have a limited distribution and are in close proximity to water sources. A site found near Rattlesnake Springs includes groundstone and projectile points. Other sites in the area contain hearths and grayware pottery. Among the historic cultural resources are Moore's Station, Hobble Spring, Sixmile Well, a historic site, and Hot Creek Ranch. The latter has an additional site number assigned to the cemetery. Other historic sites in the area include the charcoal kilns located in Fourmile and Sixmile Canyons and the towns of Tybo and Morey (BLM, 1993). The charcoal kilns at Tybo are listed on the National Register of Historical Places. While the information contained in the U.S. Bureau of Land Management site files suggests that many of the other sites are eligible for the National Register of Historical Places, recommendations have not been made for most of them.

SITES OF AMERICAN INDIAN SIGNIFICANCEThe CGTO knows that there are a variety of culturalresources contained at the Central Nevada Test Area. Information about this area comes from previous ethnographic research (Steward, 1938) and recent archaeology reports (Edwards and Johnson, 1994). The area contains a number of cultural resources of special interest to the CGTO, including hot springs, cold springs, petroglyph panels, and more than 100 archaeology sites. Earlier archaeology research conducted by the University of Nevada, Las Vegas, collected between 20,000 to 30,000 artifacts. The simple fact that so many artifacts were recovered from this small area indicated the long-term involvement of American Indian people with this site. The CGTO has requested the opportunity to visit the area as part of this EIS in order to more fully understand its cultural significance. Until this site visit occurs, it is impossible to more fully assess the cultural significance of this area.

4.4.11 Occupational and Public Health and Safety and Radiation

Radioactivity was contained during the Project Faultless test and subsequent drilling and sampling activities (DRI, 1988). A surface radiological survey conducted prior to demobilization of the Central Nevada Test Area detected no radioactivity (AEC, 1973c). A post-shot reentry hole (UC-1-P-2SR) drilled into the chimney serves as a standpipe for measuring water levels and allows samples to be taken of the water entering the chimney. The detonation caused water levels to immediately drop to 646 m (2,120 ft) (Thordarson, 1987). Water levels were observed to fluctuate over time; however, levels did not begin to rise continuously until September 1974 (ERDA, 1977).

Long-term hydrologic monitoring, conducted annually by the EPA, continues at the Project Faultless site. Numerous drillholes were established prior to the shot detonation to measure the effects on localized hydrology (Figure 4-58 ). Many of these holes were subsequently plugged and abandoned. Two hydrologic test holes, HTH-1 and HTH-2, were left open for monitoring, and Well UC-1-P-2SR remains open to allow sampling from above the shot cavity (DRI, 1988). Four wells and two springs are monitored for tritium on a yearly basis. Two wells, HTH-1 and HTH-2, are used assampling points and are presumably located downgradient and within 1,494 m (4,900 ft) of the test site. An additional abandoned postdetonation hole (UC-1-P-1S) is periodically monitored (Chapman et al., 1994). In concert with multiple, ongoing groundwater monitoring programs, samples are analyzed for tritium, gross alpha, and gross beta radiation from one or more of the following sites: drill hole UC-1-P-2SR, drill hole HTH-1, HTH-2, Hot Creek Ranch domestic water supply well, 6-Mile Well, Blue Jay Springs, and Blue Jay Maintenance Station Well (DRI, 1988).

Tritium had not been detected in concentrations above background outside the chimney well until recently. Tritium (214 pCi/L) was detected in a water sample obtained from HTH-1 at 236 m (774 ft) in July 1992. The source of the tritium remains unresolved. The detection of tritium in HTH-1 could be the result of an earlier migrating pulse, recent surface recharge, or possibly inadvertent cross-contamination of the well (Chapman et al., 1994). Tritium concentrations in water samples taken from the reentry hole in 1976 varied with the depth of the sample. Results of the analysis ranged from a maximum value of 9.2 × 108 pCi/L at a depth of 789 m (2,590 ft), or 186 m (610 ft) above the detonation point, to a low of 2,200 pCi/L at 576 m (1,189 ft), or 399 m (1,310 ft) above the detonation point. Estimates made in 1977 indicated that radionuclides would not be expected to migrate away from the cavity region until water levels reached predetonation hydraulic equilibrium, estimated to be after 1997, based on average cavity fill rates (ERDA, 1977).

The preliminary Hazard Ranking System score (EPA’s ranking system for Superfund cleanup determination) for the Central Nevada Test Area is a low score of 3.54. This score is based primarily on the assumption of a low probability for the migration of radionuclides and that there are no human drinking water receptors in the vicinity of the Central Nevada Test Area (DRI, 1988). Recent field studies by the Desert Research Institute have revealed a more complicated hydrologic system than previously thought (Chapman et al., 1994). As a result, flow away from the cavity may have begun sooner than anticipated and the existing monitoringwells may not be ideally located to intercept potential contaminant plumes.

The Central Nevada Test Area is currently being investigated as part of the DOE’s Environmental Restoration Program. The DOE will evaluate the site in consultation with the state regulatory authority to determine what investigations may be required and what responses may be appropriate.

4.4.12 Environmental Justice

Existing demographic conditions for Environmental Justice are discussed in Section 4.1.12 . This discussion includes conditions for the Central Nevada Test Area.

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