The Rebuttal Phase of the Hearing began with
DOE's first witness, DR. DENNIS W. POWERS

Dr. Powers has a Ph.D. in geology. He worked for Sandia National Laboratory from 1975-1983. While at Sandia, Dr. Powers was responsible for site characterization, geology and geophysics. He has also worked on low-level waste disposal at Ward Valley. Dr. Powers was an Assistant Professor of Geology at the University of Texas from 1983 to 1988. Since 1988, Dr. Powers has been a private consultant as a geologist.


Dr. Phillips says the WIPP site is inadequately studied. The WIPP studies are extensive and divided into three phases. During the first phase (1975-1976), the DOE conducted the site selection. During the second phase (1976-1983), the DOE conducted the WIPP site characterization and preliminary design validation program to check to see if the rocks underground were as expected. From 1984 to the present (the third phase), the DOE has focused on the long-term phenomena for the Performance Assessment.

Two major techniques were used in the geophysical study phase. These techniques were the resistivity studies and the seismic reflection studies. The RESISTIVITY STUDY covered the Land Withdrawal Area and approximately 1-mile around that border. About 10,000 measurements were taken. The SEISMIC REFLECTION STUDY covered the surveys that were conducted and focused closely on the facility in order to examine the continuity and structure of the beds. Twenty-one potash drill holes were bored around WIPP (the P-series wells). Fifteen holes were drilled specifically to study dissolution features. These drill holes included drill hole ERDA 10 in order to study deep dissolution and 6 drill holes in Nash Draw in order to study shallow dissolution. Eighteen locations were drilled to study hydrology and many pads have multiple holes (the H-series wells).

Other boreholes were drilled to study specific features other than dissolution. In 1981, the MICROGRAVITY SURVEY focused on the northern area of the Land Withdrawal Area. This survey technique responded to density variations of the rocks and changes in elevation. Sinkholes have low densities.

Geophysical logs were brought to the surface from the boreholes. A geological log is created when a geologist on-site logs the cuttings that are returned to the surface in the drilling fluid. The log does not show a perfect picture. Sending electronics down a drill hole may make various measurements. Because salt rocks are highly soluble, the DOE had to be sure the site was in an area where solution from the surface would not attack the underground site.

The Exploratory Shaft, now called the Salt Handling Shaft, and the Ventilation Shaft, now called the Waste Handling Shaft, were sunk during the Site and Preliminary Design Validation (SPDV) Phase. The facility horizon was selected and the DOE studied the formations in the shafts. The DOE checked to see if the geology matched their expectations. The shafts allowed good underground observation.

Now the DOE is continuing the characterization of the hydrology of the WIPP site, testing for Performance Assessment and looking at the interactions between the drillholes.

There is no karst in the Rustler. There is no karst at the WIPP site. There is karst in Nash Draw and in other areas of the Pecos Valley.

The DOE has never denied that WIPP-33 is in a karst area. The 1977-78 drilling was done because of concerns about nearby karst features. The DOE concluded that instead of being deep-seated features, they were higher up. The drilling of WIPP-33 was done to determine what its features were due to. The DOE did not need to turn WIPP-33 into a monitoring well. H-6 was already drilled nearby at the northwest corner of the WIPP site.

Dr. Phillips claimed that WIPP-14 is a sinkhole. Several locations of low gravity anomalies were found during the Microgravity Survey at WIPP-33, WIPP-13 and WIPP-14. However, WIPP-14 has a normal stratigraphic sequence. The rocks above the Rustler are responsible for its low density reading. The Geophysical Log for WIPP-14 shows a normal stratigraphic sequence. Dr. Phillips said there was mud at WIPP-14. When drilling, the circulating fluid carries everything up to the surface that the drill bit breaks up below. When drilling through soft mudstone, the cuttings do not come up so nicely and so are labeled mud. But the Geophysical Log shows the rocks that were expected to be there. Anhydrite One is in the "mud, mud, mud" interval. There is no mud-filled cavern. The Basic Data Report for WIPP-14 shows no caverns and the same normal stratigraphic sequence as in WIPP-34. There is a bulk density spike in the Log that is Anhydrite One. The same spike is present in the Log for WIPP-34. The density and gamma signatures are typical of this unit.

WIPP-14 was not turned into a test well. The objective was to test the theory that the gravity anomaly at WIPP-14 was a shallow feature. When that was discovered and it was determined that the Rustler was not involved, there was no need to turn WIPP-14 into a test well.

When the shafts were mapped, Dr. Powers observed siltstones, claystones, and mudstones and well established bedding planes that were fully consistent with what was to be expected. There was no brecchiation and no dissolution residues. The un-named lower member rocks showed well-exposed bedding planes that showed deposition in the original environment and no disturbance by dissolution. Washouts are a consequence of drilling with fluid in soft rock and are not indicative of karst. Water does not seep into the shaft from mudstones in the un-named lower unit. There was no open fracture in this interval. The Culebra was seeping some water and wetting the surface. This water came down the shaft and dissolved halite back several inches giving the appearance of an open fracture.

Dr. Phillips said isopach maps show a thinning of the Rustler from east to west across the site. Dr. Powers disagrees. Dr. Powers mapped the Exhaust Shaft and mapped the Rustler again, including the mudstone members. Again, Dr. Powers found well-deposited mudstone features that were undisturbed. There is a minimal amount of salt dissolution in the Rustler since the sediments were deposited. Dr. Phillips said most scientists accepted the extensive character of dissolution in the Rustler. This was the consensus early on when they did not know much about the WIPP site. Only Dr. Barrows and one other person mapped the shafts.

THE SANTA ROSA FORMATION The Santa Rosa Formation is 2 formations above the Rustler. Water was recently found in the lower Santa Rosa. This water, however, is of recent origin and is caused by the construction and operation of the WIPP surface facilities. This water was not there prior to construction because in 1978 a series of boreholes at the site showed that the Santa Rosa Formation was dry. When the first shaft was mapped it showed that the Santa Rosa Formation was dry, but in 1988 the DOE started to see water in the air intake shaft. The only source for this water is runoff from the construction. Within the Land Withdrawal Area water has only been encountered once in the Santa Rosa Formation at drill hole H-5 (in the northeast area.)

There are no indications of water or moist zones in the northern Land Withdrawal Area. In the center and southern areas it is possible to see damp areas in the drillholes and shafts. There is no flow into the drill holes. Further to the south, there is water in the Dewey Lake Redbeds especially at WQSP-6 and -6A. Between 160-180 feet bgs (below ground surface) there are fractures filled with gypsum. In the west and southwest the cementation and gypsum veins are removed at successively lower areas. Some wells like WQSP-6 have water. Some shafts have damp and moist zones. There is confusion with the Santa Rosa Formation because the water sits on top of the Dewey Lake Redbeds, but this is not part of the Dewey Lake Redbeds. Dr. Phillips said that at H3b3, just south of the repository, there was a stream of water in this interval and feeder channels to the Rustler. Dr. Barrows disagrees. The Dewey Lake Redbeds is not saturated. The Culebra is the most transmissive unit.


Dr. Powers is not a hydrologist. Dr. Powers is not a hydrogeologist. He is not a PA or PE. Some years 50 percent of Dr. Powers' business is non-DOE. Some years, it is zero. Dr. Powers is also participating in an external review panel for the proposed Yucca Mountain Nuclear Waste Repository.

The 3 wells, C2505, C2506 and C2507, show a water saturated horizon in the lower Santa Rosa Formation/Upper Dewey Lake. This is the horizon from which water is seeping into the exhaust shaft. Dr. Powers does not agree. There is not a lack of attention to the possible route of transport through the Dewey Lake Redbeds. The Dewey Lake Redbeds do not contain potable water at the WIPP site. Dr. Powers stated that the Dewey Lake Redbeds at the site has no water, though there is water south of the WIPP site in the Dewey Lake Redbeds. This water is not a transport path. However, when looking at the reports for the 3 wells, Dr. Powers agreed that the 3 wells had water levels that stayed steady for more than 600 days. Dr. Powers thinks that the water is recently seeped-in water. Dr. Powers does not think that it is groundwater because the quality of the water has a wide variation of salinity and the water quality is not like other groundwater in the area. However, when looking at the report for the 3 wells, water near the exhaust shaft was found to contain less than 10,000 total dissolved solids (TDS). If water contains less than 10,000 TDS, it is considered to be potable water. Dr. Powers said that when some of the water is running off the asphalt on the surface, it is not encountering salt and thus has a low TDS. There are other wells "near" the exhaust shaft that do have a high TDS content. Dr. Powers does not agree that only the 3 wells were tested for hydrological characteristics. The water is sitting perched on the Dewey Lake Redbeds and is only about 6" or 1 foot into the Dewey Lake Redbeds.

Dr. Powers agreed that the United States Geological Survey (USGS) said the salt was dissolved after deposition, and not as facies exchange. Dr. Powers also agreed that Lowenstein disagreed with his hypothesis in 1987 after his exhaust shaft mapping, but before his facies exchange report. However, Dr. Powers said Lowenstein's work was limited. Dr. Powers could not give any names of scientists who did not work for Sandia Labs or the DOE who agreed with his theories on dissolution.

Dr. Powers did not include Dr. Phillips' dissertation in his bibliography of 941 reports written on WIPP from 1972 - 1990.

WIPP-33 is not 3/4 of a mile [3,960 feet] from the WIPP site, but only 2425 feet from the western boundary. When WIPP-33 was drilled, it was within the WIPP site (Zone 4) - before the boundaries were reduced.

The Basic Data Report for WIPP-33 shows drilling time marked in minutes/feet. There are 5 points marked where the time is listed as zero minutes/vertical feet. This demonstrates that the drilling equipment dropped abruptly in the Rustler. In the Dewey Lake Redbeds, however, the time is rapid, but not zero minutes/vertical feet. This evidence indicates cavities or caverns. Lost circulation of drilling fluid was also noted. However, the stratigraphic profile of the entire hole was noted as "normal." In the case of WIPP-33, the statements that the stratigraphic sequence was "normal" do not mean that no caverns were encountered in the drilling process.

The Basic Data Report stated that the drillers found a normal stratigraphic sequence. In both wells this means that the sequence of the stratigraphy was normal. Under "Drilling Time," the WIPP-14 Basic Data Report states "no data." Dr. Powers does not know why no data was noted under "Drilling Time." The original Drill String Log indicates that the Caliper Log showed no drops in equipment, but it does not show any drilling times either. Elliot Geophysical Company did the Resistivity Survey. Their report refers to the sinkhole, which is the depression later drilled as WIPP-14. Elliot Geophysical concluded that it was an ordinary sinkhole due to solution caverning. This report is not published. It was not listed in the bibliography. The report is not in the reading rooms. The Elliot report was not provided to the EPA. Dr. Powers does not know why. The lithologic description in the Basic Data Report reports "mud" 5 times, totaling 71.4 vertical feet of mud, or mud with gypsum and anhydrite. Dr. Powers said that the Geophysical Log shows clearly that this is a mudstone and anhydrite interval. What is described as mud is really mudstone. Even though the drillers describe other layers as mudstone instead of mud, they were not able to give the proper description of the 71.4 feet as mudstone because they probably did not get mudstone chips back when they were drilling. However, the spike that Dr. Powers testified to before does not cover the whole 71.4 feet.

The Basic Data Report shows the drilling time. WIPP-34 was drilled near WIPP-14, but to the west. WIPP-34 was drilled first.

The H6C Lithologic Log states 4 times that mud was found in the Tamarisk and that it is 50-80% of the lithology described. The Lithologic Log states that mud was found 3 times in the lower un-named member and that it is 70-90% of the lithology described.

H6 is within the WIPP site in the northwest corner. The Log was not published in any Basic Data Report. Dr. Powers could not say why.

The H3B2 handwritten Log found mud 3 times in the Forty-Niner and describes dissolution residue. The Log states that dissolution residue in the Tamarisk is from a previously existing halite unit.

B-25 is near the center of the WIPP site. The Geologic Drilling Log states that circulation of drilling fluid was lost on numerous occasions. A memo from the USGS to the WIPP Project Office gives monthly measurements on the B-series wells (12 wells). The memo shows water levels; therefore, the wells were not dry. Dr. Powers stated that he would have to look at each of the B-wells to see where the water was stratigraphically.

The Site and Preliminary Design Validation (SPDV) Ventilation Shaft Geotechnical Data Report states 3 times that there were washouts in the Rustler Formation and that there were open fractures in the Magenta. The report shows the location of the liner plate at the bottom of the Culebra. The report also states a number of times that open fractures in the lower un-named member (12 fractures) had no fracture filling at all and some others were partly filled and partly open.

Sandia Report 79-7110, entitled "Core Study of the Rustler Formation over the WIPP Site," states that solution residue was found in WIPP-19 at numerous intervals. Dr. Powers does not agree with the Sandia Report's conclusion. Dr. Powers' report, which he co-authored, is entitled "Deformation of Evaporites Near the WIPP Site." Dr. Powers' report has an isopach map showing a greater thickness of the Rustler in the southeast and dissolution of halite beds in the Rustler progressing from east to west across the site. The report was written before he mapped the shafts and for that reason Dr. Powers no longer agrees with his report.

A list of reports was presented to Dr. Powers. All of the reports describe a westward thinning of the Rustler through dissolution. Dr. Powers disagrees with all of the reports, even though some of the reports were written and published after the mapping of the shafts. Dr. Powers said that none of the authors did any research, except for the Lowenstein report. The Lowenstein report found late stage alteration in every member of the Rustler.

In summary, Dr. Powers said that the halite members in the Rustler were deposited in a salt lake/lagoon environment mainly to the east of the WIPP site and were surrounded by large mud flats with soil features. There is no significant dissolution of salt at the WIPP site. However, as Dr. Powers said before, he can cite no published reports other than those from DOE or Sandia that agree with him.

Although Sandia/USGS Basic Data Reports for ERDA-6 through -9, etc. (12 wells) all identified dissolution residues in the Rustler, Dr. Powers disagrees with all of those reports. Also, the Basic Data Reports for P1, P4, P12, P13, P14, H11, H14, H16, H18, W11, W12, W13, W14, W18, W19, W33, W34 and DOE2 all found anhydrite converted to gypsum. Dr. Powers said there are probably more.

H-3 is 400 feet south of the WIPP waste panels. The USGS summary shows the top of the Salado at 820 feet bgs (below ground surface) and the top of the salt at 823 bgs. How could there be an anomalous borehole with no halite in the Rustler within a salt depositional environment if there is no dissolution in the Rustler? Didn't Dr. Powers say that where the halite is absent in the Rustler it is due to lack of deposition, not dissolution?

How can there be a pocket of no salt surrounded by salt? Dr. Powers cannot answer the question because he may not agree with the questioner's (Dr. Phillips) premise. Dr. Powers has prepared different maps that show things differently. Dr. Powers disagrees with Dr. Phillips' boundaries that he has drawn of the halite.

In H3 the 1988 report noted that the south, south-central area was the margin of the depositional extent of halite and if there is dissolution, this is where it would be. For the Tamarisk, this is very close to where the depositional edge is. The margin of salt deposition is not dissolution residue, though there is some dissolution along the edge. Dr. Powers places this edge to the east of H3 and there is halite for 1 to 2 miles to the west, except in H3.

If you looked across the whole region you would find different rocks even though they were all deposited at the same time. This is because there was a lake, beach, and further inland rivers and river deposits that were each different.

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