1. Spatial and temporal variations of infiltration rates and fast preferential flow in the near-surface zone depend on topography. Near-surface fast infiltration and migration of radionuclides in the unsaturated zone occur in surface depressions. Despite the low level of contamination detected in groundwater, the appearance of Chernobyl radionuclides confirms the presence of localized, preferential, radionuclide transport though the unsaturated zone.
2. Rapid groundwater contamination around Chernobyl might not be associated directly with the near-surface zones of preferential flow.
3. Section 13 of the Yucca Mountain Site Description (DIRS 151945-CRWMS M&O 2000) contains a more complete discussion of DOE’s natural analog study.

They said, "Oh, no. It’s not going to contaminate the groundwater. It’s going to be contained." These bombs are going off, they create these lasts pops underneath and that bomb is so hot, it just melts everything around it. There’s no problems here.

1. Although the consolidated rock commonly has very low permeability, and very low rates of groundwater flow, the entire groundwater system, valley-fill and bedrock, should be treated as one integral system.
2. Though vertical gradients exist between the valley-fill aquifers and consolidated bedrock aquifers, on a regional scale, the potentiometric levels are similar enough that all water level data, regardless of well construction, can be used to define regional potentiometric levels.

As described in the EIS, contaminants that may eventually escape from the repository would most likely move in thin vertical plumes through flow tubes beneath the repository. This flow model would tend to reduce the amount of contaminant dispersion and dilution compared to a model in which these contaminants would mix on a large scale with groundwater flow in the saturated zone. Dilution of contaminants is a process that would occur in the natural environment at Yucca Mountain. DOE has incorporated this process into the models of the long-term performance of the repository based on the best understanding of the site.

1. Results of extensive underground exploratory studies and investigations of the surface environment.

2. Consideration of features, events and processes that could affect repository performance over the long-term.

3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.

4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.

5. Parameter distributions that represent the possible change of the system over the long term.

6. Use of conservative assessments that lead to an overestimation of impacts.

7. Performance of sensitivity analyses.

8. Use of peer review and oversight.

The "250 to 480 acre-feet values" from the Draft EIS represent the range of expected water demand for the repository during the operational period, and not the perennial yield values. Section 4.1.3.3 of the EIS discusses the projected water demand.

• The presence of water within the proposed repository that is of recent origin (less than 50 years) indicates that ground water is percolating through the mountain at a rate that violates the DOE’s own standard for an acceptable repository site.

• At least 33 seismic faults lie close to, or within, the site. 621 earthquakes of magnitude 2.5 or greater have occurred within 50 miles of the site over the last 20 years, including a 5.6 level quake centered just 12 miles from the site in 1992. A magnitude 5 or 6 earthquake at the site could dramatically raise the water table beneath the repository, flooding the chamber and leading to a corrosive breakdown of the disposal canisters and a possible steam explosion, thereby releasing plutonium and other waste products into the air and ground water.

The intent of Table 3-18 of the Draft EIS is to show a general difference between water from the volcanic aquifers and water from the carbonate aquifer. The DOE believes this is achieved in the table without providing more complicated detail. Although lateral differences in chemical quality of water in the volcanic aquifers at Yucca Mountain are observed, other than the pronounced difference from water in the carbonate aquifer noted in the EIS, little difference in chemical or isotopic character has been noted relating to stratigraphy of the volcanic rocks.

1. An update of the assessment of the performance of the repository for the period after closure
2. A description of the postclosure monitoring program
3. A detailed description of measures to regulate or prevent activities that could impair the long-term isolation of the waste, and to preserve relevant information for use by future generations

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

Only the water quantity for the low thermal load is given here. What is the quantity for the intermediate and high thermal loads, and why were the data not given?

What would be "sufficient quantities of water" for DOE to collect? There are more than a few places in the ESF that dripped water.

Is perched water found only below the proposed repository horizon?

Why wasn’t Chlorine 36 also used here, along with tritium?

1. The fact that the water is perched between the repository horizon and the water table indicates a barrier to flow. In this case, the perching layer possesses less matrix permeability and has a smaller fracture density than the overlying rocks
2. The age of the perched water is thousands of years. The perching layer appears to impede the downward flow of water so that the water has aged substantially (thousands of years) in its current location. This increased residence time provides greater potential for diffusion and sorption of radionuclides released from a breached repository.

Define and quantify "relatively rapid water movement."

Define and quantify "very small amounts" of fallout. What is the basis for the assumption of "very small amounts" of fallout?

Give the best estimate of groundwater travel time, not just less than 10,000 years.

The Draft EIS should discuss more fully the fluid inclusion work on the calcite and opal veins and coatings underway at UNLV. The Draft EIS contains a brief discussion of the controversy over evidence that hydrothermal activity may have occurred at Yucca Mountain in the past and could reoccur during the lifetime of the repository. The text gives the misleading impression that this matter has been resolved in DOE’s favor as a result of a NAS review of the issue. In fact, the issue is the subject of an ongoing joint study being implemented by the University of Nevada Las Vegas, DOE, and the State of Nevada. Preliminary indications from data and analysis emerging from this study indicate that fluid inclusions found in calcite-silica deposits at depth within the exploratory tunnel at Yucca Mountain are of hydrothermal origin. Work is ongoing to confirm this finding and to discover the age of the fluid inclusions. The outcome of this study has significant implications for the suitability of Yucca Mountain as a repository site and for the viability of the Proposed Action as described in the Draft EIS.

Provide the actual feet/mile or meters/kilometer for the slope of the water table east of the Solitario Canyon fault.

The use of the word "probably" in the third paragraph on this page does nothing but cause one to doubt the veracity of the statement.

The statement that the groundwater pathway beneath Yucca Mountain is southerly conflicts with Figure 3-13 and other figures used in various DOE presentations that show an initial eastward flow of the groundwater, then down Fortymile Wash.

Define and quantify the term "small" as used in the sentence regarding the volume of water pumped from USW VH-1.

What type of general groundwater flow patterns changes would be expected from pumping more than 0.72 million cubic meters from the western portion of Jackass Flats? Although the Draft EIS states that the changes would be "small," the changes expected and any impacts from these changes should be discussed here.

The last sentence of this section should state that the rate of water movement through the unsaturated zone can be from 50 years to thousands of year, not less than 100 years to thousands of years, as stated in this section.

1. The need for the repository


2. Alternative sites to Yucca Mountain, or


3. Non-geological alternatives

1. A statement that such information is incomplete or unavailable.
2. A statement of the relevance of the incomplete or unavailable information to evaluating reasonably foreseeable significant adverse impacts on the human environment.
3. A summary of existing credible scientific evidence that is relevant to evaluating reasonably foreseeable significant adverse impacts on the human environment.
4. The agency’s evaluation of such impacts based upon theoretical approaches or research methods generally accepted in the scientific community.

To be in compliance with NEPA, DOE is required to consider effects of credible alternative models in the Draft EIS. While the Draft EIS recognizes differing viewpoints regarding groundwater flow and references the State of Nevada-funded studies of Lehman and Brown, 1995, there has been no evaluation of the impacts. (See Attachment U to these comments for an expanded discussion of this topic.)

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

Inyo County, California testified before DOE on the long-term threat that the Yucca Mountain repository poses to regional groundwater supplies and to communities east of Owens Valley. Studies conducted by Inyo County and Nye and Esmeralda Counties in Nevada point to the existence of a continuous aquifer running from beneath Yucca Mountain south to Tecopa, Shoshone and Death Valley Junction. These studies indicate that water flowing beneath Yucca Mountain flows generally south to become surface water and groundwater flowing into Death Valley that is used for commercial and domestic purposes and supports natural habitats. Some of these springs also support populations of a number of threatened or endangered species.

The DEIS does not contain a hydrogeologic cross-section--a basic tool for evaluating the potential impact of contaminates on groundwater--to help evaluate potential groundwater migration from the proposed repository into the Amargosa and Death Valleys. The EIS should include the cross-section as well as maps showing water level isocontours. Without this information, potential environmental impacts to groundwater in California cannot be reasonably assessed. In addition, the DEIS’ characterization of the carbonate aquifer in the vicinity of Yucca Mountain is insufficient. It appears that only a single well completed in this aquifer was tested. This method does not provide reliable data on groundwater flow direction or aquifer hydraulic conductivity. More field data are needed to enhance the computer-modeling effort. Without the actual parameters of the aquifer, it is difficult to judge the model’s reliability for predicting the fate and transport of radionuclides 10,000 years into the future.

DOE based the selection of the proposed repository block in large part on the lack of mapped surface faults in this part of Yucca Mountain. In light of the close association of the detection of chlorine-36 with mapped surface faults, DOE does not anticipate the presence of many undiscovered fast paths. Continued chlorine-36 sampling in the cross drift that would extend above the repository has not identified additional fast paths. The fast paths identified to date have been factored into the Total System Performance Assessment for the repository.

The Draft EIS was developed using the best available information for hydrochemical and geochemical characterization. Many experiments are ongoing and some of the resulting data are included in the EIS. DOE recognized that the saturated zone requires additional characterization in order to fully evaluate the effects of faults on flowpaths and the relationships between the alluvial/valley fill aquifer, volcanic aquifer, and carbonate aquifer systems. DOE initiated a Cooperative Agreement with Nye County to address a number of the characterization uncertainties mentioned in this comment and has included the available data into the Final EIS. The Nye County program is described below.

The upper volcanic aquifer shown in Figure 3-15 does not occur at the site (Topopah Spring Welded Unit - host rock for the repository). However, because the upper volcanic aquifer occurs down-gradient of the site, the EIS should address the potential pathway of contaminated plume across different hydrogeologic units, including aquicludes and faults.

The discussion about groundwater admits to uncertainties about the groundwater flow system in the region of the repository. The text does not address the on-going work being conducted by Nye County that will presumably reduce some of that uncertainty.

Although DOE has improved its understanding of the hydrologic system, uncertainties would remain given the time frame of concern (waste isolation for thousands of years). If the site was approved, DOE would institute a performance confirmation and testing program, elements of which would address the hydrologic system. The purpose of this program would be to evaluate the accuracy and adequacy of the information used to determine whether the repository would be expected to meet long-term performance objectives. The performance confirmation program, which would continue through closure of the repository (possibly as long as 300 years), would offer a means to further understanding of the hydrologic system and reduce uncertainties.

DOE believes that these findings do not indicate that the Yucca Mountain site should be declared unsuitable for development as a repository. Most of the water that infiltrates Yucca Mountain moves slowly through the matrix and fracture network of the rock, and isotopic data from water extracted from the rock matrix indicates that residence times might be as long as 10,000 years. Furthermore, after excavating more than 11 kilometers (8.4 miles) of tunnels at Yucca Mountain for the Exploratory Studies Facility, DOE determined that only one fracture was moist (there was no active flow of water). This observation has been confirmed in test alcoves that are not subject to the effects of drying from active ventilation.

DOE’s original 1984 site suitability guidelines (10 CFR Part 960) have been superseded by Yucca Mountain-specific guidelines (10 CFR Part 963) promulgated by DOE in 2001. Even though 10 CFR Part 960 no longer applies to Yucca Mountain, DOE believes that information and analyses do not support a finding that the site would have been disqualified under the groundwater travel time disqualifying condition at 10 CFR 960.4-2-1(d). Under that condition, a site would be disqualified if the expected groundwater travel time from the disturbed zone (the area in which properties would change from construction or heat) to the accessible environment would be less than 1,000 years along any pathway of likely and significant radionuclide travel. The definition of groundwater travel time in 10 CFR 960.2 specifies that the calculation of travel time is to be based on the average groundwater flux (rate of groundwater flow) as a summation of travel times for groundwater flow in discrete segments of the system. (In this case, the geologic and hydrologic subunits comprising the unsaturated and saturated zones.) As a practical matter, this definition provides for the consideration of the rate at which most of the water moves through the natural system to the accessible environment.

DOE’s original 1984 site suitability guidelines (10 CFR Part 960) have been superseded by Yucca Mountain-specific guidelines (10 CFR Part 963) promulgated by DOE in 2001. Even though 10 CFR Part 960 no longer applies to Yucca Mountain, DOE believes that information and analyses do not support a finding that the site would have been disqualified under the groundwater travel time disqualifying condition at 10 CFR 960.4-2-1(d). Under that condition, a site would be disqualified if the expected groundwater travel time from the disturbed zone (the area in which properties would change from construction or heat) to the accessible environment would be less than 1,000 years along any pathway of likely and significant radionuclide travel. The definition of groundwater travel time in 10 CFR 960.2 specifies that the calculation of travel time is to be based on the average groundwater flux (rate of groundwater flow) as a summation of travel times for groundwater flow in discrete segments of the system. (In this case, the geologic and hydrologic subunits comprising the unsaturated and saturated zones.) As a practical matter, this definition provides for the consideration of the rate at which most of the water moves through the natural system to the accessible environment.

1. The fact that water is perched between the repository horizon and the water table indicates a barrier to flow. In this case, the perching layer possesses less matrix permeability and has a smaller fracture density than the overlying rocks.
2. The age of the perched water is thousands of years despite exhibiting a geochemical and isotopic signature that supports an interpretation of relatively rapid surface-to-depth recharge (tens to hundreds of years). In other words, the perching layer is so effective in impeding the downward flow of water that the water has aged substantially (thousands of years) in its current location. This increased residence time affords greater opportunity for diffusion and sorption of radionuclides that are potentially released from a breached repository.

DOE’s original 1984 site suitability guidelines (10 CFR Part 960) have been superseded by Yucca Mountain-specific guidelines (10 CFR Part 963) promulgated by DOE in 2001. Even though 10 CFR Part 960 no longer applies to Yucca Mountain, DOE believes that information and analyses do not support a finding that the site would have been disqualified under the groundwater travel time disqualifying condition at 10 CFR 960.4-2-1(d). Under that condition, a site would be disqualified if the expected groundwater travel time from the disturbed zone (the area in which properties would change from construction or heat) to the accessible environment would be less than 1,000 years along any pathway of likely and significant radionuclide travel. The definition of groundwater travel time in 10 CFR 960.2 specifies that the calculation of travel time is to be based on the average groundwater flux (rate of groundwater flow) as a summation of travel times for groundwater flow in discrete segments of the system. (In this case, the geologic and hydrologic subunits comprising the unsaturated and saturated zones.) As a practical matter, this definition provides for the consideration of the rate at which most of the water moves through the natural system to the accessible environment.

The long-term performance assessment calculations in Chapter 5 include neptunium-237. As the comment says, this is the most significant radionuclide, in terms of dose, in the 10,000- to 1-million-year period. Expected human health impacts in Chapter 5 (which include the contribution to dose from neptunium-237) for the first million years after repository closure would decline with distance from the repository (for example, see Section 5.4.2). Chapter 3 acknowledges that a small amount of groundwater might move beyond the primary groundwater discharge point at Alkali Flat (Franklin Lake Playa) to discharge in the Furnace Creek area of Death Valley. Even if this was the case, impacts in the Furnace Creek area would be less than the low impacts described in Chapter 5 for Franklin Lake Playa because impacts would decline with distance from the repository.

"DOE has collected groundwater–level data from wells at Yucca Mountain and in neighboring areas on a routine basis since 1983, and has used the levels to which water rises in wells—called the potentiometric surface—to map the slope of the groundwater surface and to determine the direction of flow. Based on these and other data, groundwater in aquifers below Yucca Mountain and in the surrounding region flows generally south toward discharge areas in the Amargosa Desert and Death Valley (Figure 3-13)."

However, Figure 3-13 (p.3-38), which is modified from D’Agnese, et al., shows a question mark on the groundwater flow arrow from the Amargosa Desert area towards Death Valley NP [National Park]. Figure 32 in the referenced D’Agnese, et al. report (1997) is essentially identical to Figure 3-13 in the draft EIS, except that D’Agnese’s Figure 32 does not have the question mark on the subject groundwater flow arrow.

"Some zones within the central corridor (of the Regional Carbonate Aquifer) are highly transmissive, as indicated by large spring discharges that are fed by parts of the aquifers having imperceptibly sloping water tables, and by geologic mapping of ancestral flow paths. The highly transmissive zones may act as large-scale drains, collecting water from adjacent, less transmissive rock that underlies most of the study area."

He goes on to state:

"Results from tests of carbonate-rock aquifers throughout eastern and southern Nevada indicate that within 10 miles of regional springs, aquifers are an average 25 times more transmissive than they are further away."

The springs at Ash Meadows and Death Valley are high volume, constant discharge springs known to be supported by the regional aquifers. If Dettinger’s observations are correct, then the areas surrounding them are typified by accelerated groundwater transmissivities. This occurrence is further supported by the recent discovery of subterranean amphipods being discharged from the groundwater aquifers at Death Valley. The presence of these organisms necessitates the occurrence of open space fractures or voids at some considerable distance from the springs. These fractures would result in enhanced groundwater flow.

Sparse potentiometric data indicate that a divide could exist in the Funeral Mountains between the Amargosa Desert and Death Valley. Such a divide would limit discharge from the shallow flow system, but would not necessarily affect the deeper carbonate flow system that could contribute discharge to the Furnace Creek area (DIRS 100465-Luckey et al. 1996). Geochemical, isotopic, and temperature data indicate that water discharging from springs in the Furnace Creek area is a mixture of water from basin-fill aquifers in the northwestern Amargosa Desert and the deeper flow in the regional carbonate aquifer (DIRS 101167-Winograd and Thordarson 1975). The groundwater in the northwestern part of the Amargosa Desert originates in the Amargosa River drainage in Oasis Valley and from the eastern slope of the Funeral Mountains, both of which are west of the flow paths that extend south from Yucca Mountain. Even if part of the flow from Yucca Mountain mixed into the carbonate pathway that supplies the Furnace Creek springs, it would be too little to affect the springflow chemistry noticeably. Considering the small fraction of water that would infiltrate though the repository footprint (approximately 0.2 percent or less) compared to the total amount of water flowing through the basin and the large distances involved [more than 60 kilometers (37 miles) from the source], any component from Yucca Mountain in this very long and complicated flow path would be diluted to such an extent that it would be undetectable.

Groundwater flows in aquifers below Yucca Mountain are generally to the south. Therefore, radionuclides and toxic chemicals, if introduced to the groundwater either by a short-term catastrophic event (e.g., earthquake, flood) or through long-term (i.e., more than 1,000 years) degradation of the waste storage containers, could eventually migrate to environmentally sensitive areas such as Ash Meadows NWR [National Wildlife Refuge]. A recent study found that the plutonium compound PuO₂, once thought to be the most stable form of plutonium waste, can be oxidized by water making it more soluble and increasing the risk of groundwater contamination from storage facilities (Haschke et al. 2000).

1. The need for the repository


2. Alternatives sites to Yucca Mountain, or


3. Non-geological alternatives

1. A statement that such information is incomplete or unavailable.
2. A statement of the relevance of the incomplete or unavailable information to evaluating reasonably foreseeable significant adverse impacts on the human environment.
3. A summary of existing credible scientific evidence which is relevant to evaluating reasonably foreseeable significant adverse impacts on the human environment.
4. The agency’s evaluation of such impacts based upon theoretical approaches or research methods generally accepted in the scientific community.

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

Addressing the commenter’s concerns about radioactive leaks from the repository affecting surface-water springs, the assessment of long-term repository performance described in Chapter 5 does not address such a scenario primarily because there are no springs along the groundwater flow path between Yucca Mountain and Alkali Flat, which is the area farthest from the repository for which DOE estimated impacts. In addition, the use of spring water would not represent a higher risk to water users than that assumed for the groundwater exposure scenario examined by DOE. That scenario includes residents using and consuming groundwater and consuming crops and livestock watered with groundwater. Finally, springs in Death Valley that may discharge some water from the Yucca Mountain area are farther from the repository than Alkali Flat. As a consequence, potential contaminant levels and exposure impacts in Death Valley would be lower than those estimated at Alkali Flat (modeling shows that doses resulting from contaminant releases would be within the regulatory limits established by EPA in 40 CFR Part 197).

The Yucca Mountain Site Description (DIRS 151945-CRWMS M&O 2000) cites reports that contain the results of in-place stress tests at and near Yucca Mountain. That document also summarizes estimated in-place stress at the repository level and the results of more recent testing in the Drift Scale Test block. Section 11 of the Site Description describes the integrated system response to the heat generated by emplaced waste. That section considers the part of the natural system, the near-field environment zone, that thermal effects would permanently alter. Although the far-field environment could have slightly elevated temperatures, it would remain essentially unaltered (DIRS 151945-CRWMS M&O 2000).

7.5.3.2 (9791)
Comment - EIS001888 / 0376
[Clark County summary of comments it has received from the public.]

This contaminated tritium was from the nuclear explosions that would explode into the air, the contamination would come down, fall on the surface and then with the rain water that was falling on the mountain would be carried 500 feet below the surface of the ground. The water is moving through Yucca Mountain. Friends of mine went out to Yucca Mountain just a couple weeks ago, about a month ago, actually, and took a tour of the Yucca Mountain, and where the gentleman was talking about where they’re heating up the rocks, there is water pouring out of those rocks.

There are puddles of water on the floor, condensation all over the tunnel, and the people at Yucca Mountain were trying to shield it, trying to put up these aluminum shields to hide that water so that it would go around these shields and underneath the walkway so that the people walking through there couldn’t see the water.

The quotation above reflects lack of objectivity in the DOE’s handling of the controversy. First, experts who conducted the review for the DOE may hardly be called "independent," since all these scientists were promoting the "non-inundation" scenario for years.³ Second, it is unfair and misleading not to mention written opinions of three truly independent experts from the Europe (selected for their outstanding scientific expertise in fluid inclusions and non-involvement in the Yucca Mountain studies),⁴ attached to the report. All three reviewers concurred in the opinion that the fluid inclusion work is of high quality, and interpretations are reasonable.

Finally, a DOE-sponsored verification fluid inclusion research project presently underway at University of Nevada at Las Vegas, UNLV, has already (as of July, 1999) confirmed the presence of the two-phase fluid inclusions, yielding elevated homogenization temperatures in secondary calcite and quartz from ESF.

1. The USGS geologists inferred elevated, up to 120ºC, temperatures for paragenetically early secondary silica from ESF on the basis of stable isotopic studies.⁶

2. Based on yet another method, structural studies of calcite, Mary Beth Gray with co-authors (contractors to NRC) concluded that calcite in fault rock in the ESF were formed at elevated temperatures (probably, 150-200ºC), and there have been more than one event of calcite deposition (Gray et al. 1998).

3. Terry Else with co-authors (1999) have found viable moderately thermophilic calcite-depositing bacteria (temperatures of habitat 40-60ºC) in calcite sample that yielded homogenization temperatures of 35-50ºC; adjacent bedrock tuffs did not contain such bacteria.

4. Preliminary data on stable isotopic gradients in surficial calcite at Yucca Mountain suggest the progressive evaporation, CO₂ degassing and perhaps cooling -- features consistent with travertine origin and inconsistent with pedogenic origin of these deposits (Dublyansky and Szymanski 1996; Dublyansky et al. 1998). Prof. John Valley, who evaluated this work for the U.S. NWTRB [Nuclear Waste Technical Review Board], concurred with this interpretation (with one reservation that the presence of these trends needs to be verified).⁷

1. There presently exists significant body of evidence, indicating that inundation of the repository zone by upwelling hot waters.

2. The ages of these events are presently not known with certainty; extensive preliminary data indicate, however, that they occurred intermittently between 9 million years and 8 thousand years ago.

3. Based on the present evidence, it is reasonable to conclude that the probability of occurrence of inundation is greater than the 1 x 10^-8 per year DOE level of concern, which means that the hydrothermal hazard probabilistic analysis must be carried out.

4. Potential consequences of inundation of the repository filled with high-level nuclear waste may be disastrous for the environment and people.

5. Draft EIS does not consider the inundation scenario.

⁶"Delta-¹⁸O values of the silica phases quartz, chalcedony, and opal indicate that some of the early massive-silica-stage phases must have formed from heated water..." Whelan et al. 1998, p.21.

The DEIS consistently underestimates the potential of leaching from the site to adversely impact surface and groundwater in the region. The site drains into the Amargosa River system which drains an area of 3,100 square miles. The area encompassed by these water resources includes Death Valley National Monument as well as many small and growing communities in Nevada and California: Tecopa Springs, Pahrump and Amargosa Valley. Furthermore, the area is subject to flash flooding and volcanic activity which can alter the water courses in unexpected ways. The DEIS minimizes the possibility of high rainfall events and assumes that the meteorology in the area will remain stable for centuries. Such absurd assumptions cannot be used as the basis for a purportedly scientific assessment of the risks to water resources.

http://www.uark.edu/depts/agronomy/scott/research.html

you will find a set of draft papers that describe a new quasi-analytic exact solution to Richards’ equation for unsaturated flow. Saying that it is a "general" solution is my mistake, not Dr. Scott’s. The approach only works for inflow wetting fronts that are monotonic in space. Nevertheless, it works for a variety of boundary conditions, including constant head and constant inflow in both the horizontal and vertical.

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

In response to this comment, DOE has changed the term "steep gradient" to "large gradient."

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

Recent work (publications and draft papers on www.aquarien.com) in numerical methods for modeling the vertical unsaturated flow of water in porous media has uncovered previously unrecognized errors in standard methods. These errors may affect the validity and reliability of models that attempt to predict the flow of water and the transport of hazardous and nuclear waste on the scale of tens to thousands of years. The following questions and three-point grid test demonstrate how the common arithmetic mean of intergrid unsaturated hydraulic conductivity violates Darcy’s law for vertical unsaturated flow in all but a few trivial conditions, and can even violate the mathematical minimum-maximum principle for elliptic boundary value problems (steady-state flow problems). By contrast, a Darcian intergrid conductivity mean for the exponential pressure-conductivity relation solves such problems perfectly. The numerical examples in the appendix compare parallel models of a relaxing wet pulse in a long, vertical fracture, using the exponential pressure-conductivity relation. One model uses the arithmetic mean, and the other the analytic Darcian mean, with exactly the same adaptive time steps for both. The arithmetic mean model exhibits a dry spike that grows with the logarithm of time, and oscillations similar to numerical dispersion, both associated with space steps where the arithmetic mean can violate the min-max principle. By contrast, the Darcian mean model is smooth and well-behaved.

7.5.3.3 Seismicity

7.5.3.3 (369)
Comment - EIS000045 / 0002
The draft EIS does not consider the risk of a major subterranean plate shift despite the very recent history of seismic activity. It only considers the actual movement of the ground at the site and the effect it will have on the processing facility and the canisters. The effect of a major plate shift on the water table was not considered. The last 20 years of history shows that the ability to predict such occurrences is not reliable. An example would be (within that 20 years) The earthquake near Arco, Idaho. The valley floor dropped 5 feet or more, water from the under ground aquifer sprang up as springs and lakes that never existed prior. Waverly Person, chief of the US Geological Survey’s Earthquake Information Center, says "...There is no scientific way of predicting or forecasting." When speaking about earthquakes.

Response
DOE has maintained a network of water level monitoring boreholes in the area of the proposed repository site and the surrounding region since the early days of site characterization. Observations of water level elevation under normal conditions (that is, not transiently seismically influenced) indicate very minor changes (a few tenths of a meter) annually due to seasonal climatic variation in precipitation in this region. Several of the boreholes record water levels continuously or at short intervals (several times an hour), and thus have recorded the response of the water table to both local earthquakes (Little Skull Mountain, magnitude 5.6) and regional earthquakes (some as large as magnitude 7.3, such as the Landers, California, earthquake, on June 28, 1992) for almost two decades. In general, departures from long-term average water table elevation are minor, usually limited from a few centimeters to, at most, about 1 meter. These changes tend to be short-lived, with most monitored boreholes showing a return to pre-earthquake water levels within a few hours to a few days. In no instance has the network recorded any large permanent departures from pre-earthquake water levels.

DOE has gained additional confidence in this conclusion from other site characterization activities. Evidence from paleodischarge sites in the vicinity of Yucca Mountain and mineralogical data from deep boreholes at the site indicates that at no time in the geologic past has the regional water table been more than about 120 meters (390 feet) higher than it is at present. Given that the general elevation of the proposed repository would be at least 160 and up to 400 meters (520 up to 1,300 feet) above the present water table elevation, effects in response to earthquakes would be expected to be relatively minor and would not pose problems for repository safety.

7.5.3.3 (596)
Comment - EIS000127 / 0013
They consider earthquakes to be strong enough to completely demolish both the waste handling and the waste -- the other waste building that they plan on running the waste throughout there.

They figure both those buildings would collapse in an earthquake on top of the waste that’s in ‘em, and yet nothing is going to happen to a single one of those holes that they bored through that porous rock that’s full of all those holes -- all these fissures per meter. It’s not even considered at all.

Response
An extensive seismic hazard analysis was completed in 1998 involving 25 experts from industry, academia, and government. The expert assessments indicate that the geologic fault displacement hazard is generally low. Results of long-term performance assessments of the subsurface repository indicated no significant effects on waste isolation from earthquakes. The surface and underground facilities at Yucca Mountain are being designed to withstand ground motion from earthquakes. The analysis determined that an annual frequency of 1 10^-4, or the 10,000-year earthquake, is an appropriate level for preclosure design of structures that are important to safety. At Yucca Mountain, these structures will be designed to withstand horizontal ground motion with an annual frequency of occurrence of 1 10^-4. For the 10,000-year earthquake, the design motions are dominated by the contribution of a normal-fault type earthquakes of magnitude 6.3 with an epicenter within 5 kilometers (3 miles) of Yucca Mountain that respond to higher structural frequencies. At lower frequencies, contributions from strike-slip type earthquakes of magnitude 7.5 or greater events in Death Valley [within 50 kilometers (31 miles) of Yucca Mountain] are also important contributors to ground motions. The uncertainties in the magnitude and location of the earthquakes are incorporated into these analyses. DOE regards this annual frequency as appropriate and conservative because it reflects the annual probabilities of design ground motions for nuclear powerplants in the western U.S. In addition, surface facilities at Yucca Mountain pose less risk than nuclear powerplants. Table 4-36 of the EIS presents earthquake-accident scenarios that use an earthquake frequency of once in 50,000 years. This is roughly equivalent to an earthquake of 7 magnitude on the Richter scale within 5 kilometers of Yucca Mountain, with a mean peak ground acceleration of 1.1 g, where g is acceleration due to gravity (980 centimeters per second squared) at the waste-emplacement depth. These are very conservative calculations that give an indication of the maximum impact of such an event. Subsurface facilities would be built in solid rock. Because vibratory ground motion decreases with depth, earthquakes would have less affect on subsurface facilities than on surface facilities. Inspection of existing tunnels in the Yucca Mountain area has revealed little evidence of disturbance after earthquakes. Vibratory ground motion from earthquakes that might occur along faults in the Yucca Mountain region will propagate through the rock at wavelengths that are very long compared to the dimensions of emplacement drifts, boreholes, and fissures. For instance, a 1-Hertz seismic shear wave propagating with a velocity of 610 meters (2,000 feet) per second (an approximate value for the near-surface rocks) has a wavelength of 610 meters; a 10-Hertz wave has a wavelength of 61 meters (200 feet). Even wavelengths as long as 61 meters are much larger than the diameter of the proposed emplacement drifts and any previously drilled boreholes. This implies that significant strains associated with the passage of earthquake-excited seismic waves are not set up across the drifts or boreholes. An excavation tends to move as a unit and therefore the impact is minimal.

7.5.3.3 (724)
Comment - EIS000210 / 0002
It is my hypothesis that as greenhouse gasses continue to be added to the atmosphere over the next several hundred years, global climate change will be exacerbated by ever increasing severe weather events with very large water mass shifts geographically. So what? You might say ... What has that got to do with Yucca Mountain? Well, as the continental plates experience large mass load shifting, does it not stand to reason that there will be an increased incidence of seismic activity? But nuclear power does not produce any CO2, you might add; but it does produce Pu238 which may be released to the biosphere during a seismic cataclysm.

Response
DOE used several geophysical methods, including seismic reflection, gravity, and magnetic surveys, to characterize the subsurface geologic structure of Yucca Mountain. A single magnetotelluric line and several vertical seismic profiles provided supplementary information.

DOE conducted a 32-kilometer (20-mile)-long seismic reflection survey across Bare Mountain, Crater Flat, Yucca Mountain, Midway Valley, and Fortymile Wash. Where this regional profile crosses the repository site, the reflection data show a series of west-dipping normal faults that displace volcanic rocks and the Tertiary/pre-Tertiary contact at depth. DOE collected gravity data along geophysical survey lines and used them to interpret general regional structure and to aid in interpretation of the shallow structure at Yucca Mountain, such as the location and displacement of faults. The Department conducted ground magnetic surveys to infer fault locations and displacements. Because buried faults and geologic heterogeneities at Yucca Mountain are a concern for the long-term performance of the repository, DOE used magnetotelluric methods to detect and characterize these features.

DOE combined information from these geophysical studies with results from other field studies, included extensive surface mapping of geologic features and mapping in the Exploratory Studies Facility. In addition, boreholes provided information on the vertical and lateral distribution of hydrogeologic units, hydrologic properties of the rocks, thermal and other geophysical conditions and properties, chemistry of the contained fluids, pneumatic pressure, and water content and potential. Additional data for some of these parameters came from the excavations for the Exploratory Studies Facility and from boreholes drilled from the drifts or alcoves in the Exploratory Studies Facility.

Using this combined data set, DOE derived detailed geologic and hydrologic models to describe the spatial models of rock layers, faults, rock properties, and mineral distributions in the subsurface and to simulate three-dimensional fluid flow and support site-performance models of Yucca Mountain. For a more complete discussion of site-scale geophysical studies, see Section 4.6.5 of the Yucca Mountain Site Description (

Since the western Mojave desert faults are now "talking" to other faults the public needs to know the consequences. Further study is needed in this area immediately.

1. To address comments that criticized the omission of essential details of the criteria and methodology for evaluating the suitability of the Yucca Mountain site.
2. To update the criteria and methodology for assessing site suitability based on the most current technical and scientific understanding of the performance of a potential repository, as reflected in the DOE report, Viability Assessment of a Repository at Yucca Mountain (DIRS 101779-DOE 1998).

ⁱ In the Aug Las Vegas Review-Journal Steve Frishman stated that more than 600 earthquakes of magnitude 2.5 or more, large enough to feel if one is near the epicenter, have been measured within 50 miles of Yucca Mountain since 1910.

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

Define the "active life of the repository."

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

"DOE based the design on ground motion and fault displacement that could be associated with future earthquakes at Yucca Mountain on the record of historic earthquakes in the Great Basin, evaluation of prehistoric earthquakes based on investigations of the faults at Yucca Mountain, and observations of ground motions associated with modern earthquakes..."

Later in this section, it is stated that:

"DOE needs to complete additional investigations of ground motion site effects before it can produce the final seismic design basis for the surface facilities."

Further, it is stated in this same section that:

"A recent study...claims that the crustal strain rate in the Yucca Mountain area are at least an order of magnitude higher than would be predicted from the Quaternary volcanic and tectonic history of the area. If higher strain rates are present, the potential volcanic and seismic hazards would be underestimated on the basis of the long-term geologic record. If the higher strain rates are confirmed, DOE will reassess the volcanic and seismic hazard at Yucca Mountain."

It would appear from these statements the DOE has potentially underestimated the potential volcanic and seismic hazards at the proposed site. The DOE acknowledges the need for additional studies before it is able to assess the effects of the earthquake hazard on the proposed repository. The NPS [National Park Service] is concerned what this deficiency might mean for the assessment of potential risks of release of radionuclides into the environment (specifically the regional ground-water flow system that underlies the proposed repository) and exposure to down gradient springs in Death Valley NP [National Park].

A diagram is needed for low-angle normal faults, such as in Calico Hills east, and Bare Mountain west, of Yucca Mountain.

With regard to the inherent uncertainty associated with geologic data, analyses, and models, and the confidence in estimates of long-term repository performance, Section 5.2.4 explains how DOE dealt with these issues. Briefly, DOE acknowledges that it is not possible to predict with certainty what will occur thousands of years into the future. The National Academy of Sciences, the Environmental Protection Agency, and the Nuclear Regulatory Commission also recognize the difficulty of predicting the behavior of complex natural and engineered barrier systems over long time periods. The Commission regulations (see 10 CFR Part 63) acknowledge that absolute proof is not to be had in the ordinary sense of the word, and the Environmental Protection Agency has determined (see 40 CFR Part 197) that reasonable expectation, which requires less than absolute proof, is the appropriate test of compliance.

1. Results of extensive underground exploratory studies and investigations of the surface environment.

2. Consideration of features, events and processes that could affect repository performance over the long-term.

3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.

4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.

5. Parameter distributions that represent the possible change of the system over the long term.

6. Use of conservative assessments that lead to an overestimation of impacts.

7. Performance of sensitivity analyses.

8. Use of peer review and oversight.

1. Results of extensive underground exploratory studies and investigations of the surface environment.
2. Consideration of features, events and processes that could affect repository performance over the long-term.
3. Evaluation of a range of scenarios, including the normal evolution of the disposal system under the expected thermal, hydrologic, chemical and mechanical conditions; altered conditions due to natural processes such as changes in climate; human intrusion or actions such as the use of water supply wells, irrigation of crops, exploratory drilling; and low probability events such as volcanoes, earthquakes, and nuclear criticality.
4. Development of alternative conceptual and numerical models to represent the features, events and processes of a particular scenario and to simulate system performance for that scenario.
5. Parameter distributions that represent the possible change of the system over the long term.
6. Use of conservative assessments that lead to an overestimation of impacts.
7. Performance of sensitivity analyses.
8. Use of peer review and oversight.

⁴Nevada Agency for Nuclear Projects. Earthquakes: magnitude 2.5 and Greater in the Vicinity of the Proposed Yucca Mountain Nuclear Waste Storage and Disposal Sites from 1976-1996. (Data Source: Council of the National Seismic System Composite Catalog, 1976 to present, Southern Great Basin Seismic Network) Nevada Nuclear Waste Policy News, Volume 7, Issue 1. Carson City, Nevada, July 1997.

A panel of recognized experts in volcanism reviewed extensive information on volcanic activity in the Yucca Mountain region to assess the probability of disruption of a repository at Yucca Mountain by a volcanic event. The results of the hazard assessment indicated that the aggregate expected annual frequency of intersection of the repository footprint by a volcanic event is 1.5 10^-8, or approximately 1 chance in 7,000 during the first 10,000 years after closure (1 chance in 70 million annually). This estimate was recalculated in Section 3.1.3.1 of the Final EIS to account for the current footprint of the proposed repository. The revised estimate increases to about 1 chance in 6,300 during the first 10,000 years with the current repository layout, considering both primary and contingency blocks (DIRS 151945-CRWMS M&O 2000). The rocks at Yucca Mountain were formed 7 to 15 million years ago by large silicic ash flows that were erupted during a period of intense tectonic activity. The volcanism that produced these ash flows is complete and, based on the geology of similar volcanic systems in the Great Basin, additional large volume silicic activity is unlikely. Less explosive and much smaller volume basaltic volcanism in the Yucca Mountain region began about 11 million years ago as silicic eruptions waned and continued as recently as 70,000 to 90,000 years ago (see Section 3.1.3.1 of the EIS).

Again, there is uncertainty associated with the age of the Lathrop Wells volcano. The latest activity could have been thousands of years more recent than the 75,000 year age indicated.

The estimated probability of a dike disrupting the repository during the first 10,000 years after closure has uncertainty associated with it. The expert panel members’ estimates of the annual probability ranged over about three orders of magnitude, and the probability indicated here represents an aggregation of the members’ estimates.

"...DOE convened the panel of recognized experts...to assess uncertainties associated with the data and models used to evaluate the potential for disruption of the potential Yucca Mountain Repository by a volcanic intrusion (dike). The panel estimated the probability of a dike disrupting the repository during the first 10,000 years after closure to be 1 chance in 7,000."

However, the draft EIS does not evaluate the effects from such a disruption occurring. No discussion is included as to the structural integrity of radioactive waste canisters if such an event should occur, and what such disruption might mean for the possibility of leakage and transport of radioactive constituents away from the proposed repository and into the regional groundwater flow systems.

7.5.3.4 (8828)
Comment - EIS000869 / 0009
Paragraphs one and two of S.4.1.3. Geology, address the lack of volcanic activity in the area. The Cascade mountain range was inactive until Mount St. Helens erupted in May 1980. There has also been increased volcanic activity worldwide. The assurances of "the chance of volcanic disruption ... during the first 10,000 years after closure would be 1 in 7,000" are probably similar to what residents of Mount St. Helens were told for years prior to the eruption. I believe that these are misleading numbers and assumptions on the geology of the Yucca Mountain area.

We don’t even go to visit it, but you know there’s been volcanic activity in this region many, many times.

Commenters also requested deterministic evaluations of both direct and indirect effects on the repository from volcanic activity.

The area was assessed as low risk, but there has been an important study since then. Geologist Brian Wernicke and colleagues conducted a study using the Global Positioning System (GPS). Between 1991 and 1997, they used the GPS to measure crustal expansion between two different satellites on Yucca Mountain. This study produced results very different than the results from previous studies. According to previous studies, the distance between the two satellites was not supposed to change at all. However, the distance between the two satellites changed 1.7 mm, showing that the movement of the Earth’s crust in this area is much greater than previously thought and accelerating. Wernicke suggested that the possibility of a volcano could be ten times higher than previously thought.

This section only briefly addresses Biological Resources and Soils, referring to the Environmental Baseline Files (TRW 1999k and TRW 1991). The discussion in this section omits the physical environment that, together with the biological components, comprise the ecosystem involved. Ecosystems are not discussed at all, and that level of ecological organization is ignored. The same is true for the discussions of Biological Resources related to transportation on pages 3-107 and 3-127. With respect to ecosystems, the Draft EIS states on page 3-59 that many of its studies for this aspect of the document "....did not use an integrated ecosystem approach and, therefore, are of little value for evaluating impacts of the repository." This deficiency negates the sufficiency and credibility of the biological and ecological aspects of the entire Draft EIS. Further discussion of this matter appears in Westman (1985), Wiesner (1995), Salk and others (1998), Caldwell (1998), Clark and Canter (1997), Ortolano (1997), Gilpin (1997), and Bartlett and Malone (1993), as well as in Attachments D, E, F, and N to these comments.

The fact that DOE did not address the ecosystem level of organization for the Draft EIS renders an accurate interpretation of ecological impact assessment impossible. Attachments [to this comment document] G, F, H, I, J, K, and L discuss this issue, as do Westman (1985), Bartlett and Malone (1993), Salk and others (1998), Wiesner (1995), Caldwell (1998), Clark and Canter (1997), Ortolano (1997), and Gilpin (1997).

This section addresses biological and soil resources for Yucca Mountain. No meaningful or substantive information is given and addressed, so the short section is meaningless.

In the summary EIS I just have a small passage, surface soil temperatures could increase by as much by as 5.4° Fahrenheit in dry soil at a depth of 3.3 feet, which could affect root growth and the growth of microbes or nutrient availability. Potential impacts from the repository on biological resources would consist of an increase of heat tolerant species and a decrease of less heat tolerant species.

DOE carefully reviewed relevant publications prepared by the Nevada Nuclear Waste Project Office and concluded that they generally dealt with site characterization studies or were not applicable to the level of analysis appropriate for this EIS.

Yucca Mountain is at the northern edge of the range for the desert tortoise (Gopherus agassizii) which is listed as threatened under the ESA. On July 23, 1997, the Service issued a biological opinion to DOE for programmatic activities associated with site characterization studies at Yucca Mountain (File No. 1-5-96-F-307R).

Commenters stated that the EIS, based on field surveys prior to further ground disturbance, should thoroughly examine the impacts to biological/natural resources during all phases of repository development. Commenters suggested that the analyses address: (1) critical habitats for threatened, endangered, and sensitive species, including impacts from radiation exposure during accident-free operations and from accidents.

In the same section the EIS states that although Native American representatives have identified several sites, areas, or resources in the vicinity of the repository, construction of the facilities would not have any direct impacts on these important places. However, DOE does recognize that construction and operation of the repository at Yucca Mountain would have continuing adverse impacts for Native Americans who view the past, ongoing, and future repository-related activities as an intrusion on a culturally important and sacred landscape. The Department would continue to interact with Native Americans to ensure that such adverse effects are minimized to the fullest extent possible.

• Section 3.1.6.1 (Affected Environment-Archeological and Historic Resources) states that a field survey of a 44-km² (11,000 acres) parcel was conducted. Clarifying information needs to be provided, including (i) the type of survey (e.g., walk-over); (ii) the percentage of coverage for the 44-km² area; (iii) the relationship of the survey area to the entire land withdrawal area; (iv) the relationship of this survey to the "additional archaeological surveys" conducted in Midway Valley, Yucca Wash, and lower Fortymile Canyon; (v) the extent and techniques used for these additional surveys; (vi) specification of the total survey area; and (vii) the extent to which sites have been identified for the complete land withdrawal area.

• Section 3.1.6.1 (Affected Environment-Archeological and Historic Resources) of the DEIS states that "826 archeological sites have been discovered in the analyzed land withdrawal area." This statement requires clarification. It is not clear whether the entire 600 km² parcel has been surveyed or whether the number of sites is on a smaller parcel of land. It is difficult to assess site density and cultural resources impacts without knowing the extent of the land area that has been surveyed.

• Section 3.1.6.1 (Affected Environment-Archeological and Historic Resources) states that limited test excavations were conducted at 29 sites. Clarification is required regarding the criteria used to select sites for testing and the representativeness of these sites for the potentially affected area.

1. Programmatic Agreement Among the United States Department of Energy, The Advisory Council on Historic Preservation and the Nevada State Historic Preservation Officer for the First Nuclear Waste Deep Geologic Repository Program, Yucca Mountain, Nevada. (DIRS 157145-Gertz 1988)
2. Research Design and Data Recovery Plan for Yucca Mountain Site Characterization Project (DIRS 103196-DOE 1990)
3. Environmental Field Activity Plan for Archaeological Resources (DIRS 103198-YMP 1992)
4. Branch Technical Procedures: Field Archaeology (DIRS 157150-DRI 1990)

• Avoid the impact altogether by not taking a certain action or parts of an action.

• Minimize impacts by limiting the degree or magnitude of the action and its implementation.

• Repair, rehabilitate, or restore the affected environment.

• Reduce or eliminate the impact over time by preservation or maintenance operations during the life of the action.

• Compensate for the impact by replacing substitute resources or environments.

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