Citizens For Alternatives to Radioactive Dumping

Mescalero caliche
DOE states that the Mescalero caliche is “extremely impermeable” to rainwater infiltration (Comment No. 273.X.B.4, p. 28). DOE claims that since the Mescalero caliche began to form, climatic conditions “have not varied enough to remove the caliche.” (Comment No. 273-I-5, p. 5). DOE made similar statements to EPA, saying that “Mescalero caliche is typically present beneath the sand” (EPA Docket # A-93-02, Item # III-B-3, pp. 58-59), that it “covers the WIPP area as a hard, caliche crust” (Id., p. 43), and that Mescalero caliche “is expected to be continuous over large areas” (CCA, p. 2-60). To the contrary, the Mescalero caliche is not a barrier to rainwater infiltration. Up to 15% of the Mescalero caliche has been dissolved away, leaving surficial sands in direct contact with fractured sandstone (Phillips, 1987, pp. 89-92, 99-108) or siltstone (Phillips, 1987, pp. 139-155).

Caliches are essentially limestones, composed of calcium carbonate, a readily soluble material. If available moisture is sufficient, they may develop karstic landforms such as sinkholes, solution pipes, and discontinuous drainage. Much of the cemented caliche caprock may be practically impermeable, preventing infiltration of rainwater into underlying formations. However, soil water reaching the impermeable layer will migrate along the caliche surface until it finds an opening, perhaps a fracture, or a hole created by a taproot, where the water will again move downward, enlarging the opening by solution as it does so; or it may collect in depressions on the caliche surface and initiate dissolution there (Phillips, 1987, pp. 62-66, 70-72). The result is a perforated caprock that funnels water into the karst in much the same way as sinkholes (Phillips and Snow, 1998, p. 7).

Direct Testimony: Exhibit 16

Extending into the southwestern part of the WIPP site is a karst valley one mile long, 200 to 1000 feet wide, and nine feet deep (Phillips, 1987, Figure 34) [Exhibit 12. Olive (1957, pp. 351-358, cited by Phillips and Snow, 1998, p. 8) calls them solution-subsidence troughs, formed by collapse of surface rocks into underground caverns. With each collapse, the underground streams establish new channels along nearby fractures. Thus the troughs are not the result of the collapse of a single cavern but of several.

Trench exposures in the karst valley (Phillips, 1987, pp. 139-155) revealed fifteen solution pipes, 1 to 14 feet in diameter, most of them passing entirely through the caliche caprock (Phillips, 1987, Table 2). The largest of the solution pipes displays collapse in the Dewey Lake Redbeds, probably due to deep-seated solution processes (Phillips, 1987, Plate 6) [Exhibit 13]. Some of the solution pipes are floored by caliche and hold water, at least for a time; mesquite bushes thrive at these locations, and so they are called “flower-pot structures.” (Phillips, 1987, Plate 10) [Exhibit 14]. In other places the caliche is mostly gone, leaving widely separated caliche remnants exposed in the trenches (Phillips, 1987, Plates 8 and 9) [Exhibit 15 and Exhibit 16]. In some places, solution activity has leached much of the carbonate, leaving the caliche surface pockmarked with solution pits (Phillips, 1987, Plate 12) [Exhibit 17]. In some of the solution pipes, all that remains of the caliche is a powdery dissolution residue exposed in the walls of the trenches (Phillips, Plates 7 and 14) [Exhibit 18 and Exhibit 19]. In others, there is no carbonate remaining; solution processes are complete (Phillips, 1987, Plate 13) [Exhibit 20]. Of the total spatial extent of the backhoe trenches, 15.3% of the caliche surface is missing, and another 4.5% consists of Direct Testimony: Exhibit 19 flower-pot structures floored by caliche (Phillips, 1987, pp. 153, 155). A smooth, continuous, impervious caliche surface cannot be expected in buried caliche profiles; the effect is more like holes in Swiss cheese (Phillips, 1987, Plate 11) [Exhibit 21]. After heavy rainstorms, water runs along the caliche surface until it disappears into the solution pipes. Some of the water then finds its way through joints and feeder channels in the Dewey Lake Redbeds to solution channels in the Rustler Formation (Phillips, 1987, pp. 155-158).

DOE also states that the caliche has not collapsed, except along the margins of Nash Draw (Comment No. 273-I-5, pp. 5-6). To the contrary, surface collapse is visible at the WIPP-33 sinkhole, where a caliche escarpment stands 2 to 3 feet above the rim of the depression and 30 feet above the floor of the depression. Moreover, the WIPP-33 borehole found 40 feet of alluvial fill above the Dewey Lake Redbeds; thus, the structural relief of the WIPP-33 depression is 70 feet (Phillips, 1987, pp. 87-89). Backhoe trenches at the foot of the caliche escarpment revealed solution-enlarged fractures in Gatuna sandstone, where water has dissolved the carbonate cement (Phillips, 1987, Plates 2 and 3) [Exhibits 22 and 23].

Backhoe trenches were also excavated at the WIPP-14 sinkhole, which straddles the northern boundary of the WIPP site. The WIPP-14 sinkhole is 600 feet in diameter and nine Direct Testimony: Exhibit 24 feet deep (Phillips, 1987, Figure 64) [Exhibit 24], with five ephemeral water courses draining into it, and fifteen feet of alluvial fill within it. There is no evidence of surface collapse, although such collapse could be obscured by up to ten feet of sand that has accumulated on the rim of the depression (Phillips, 1987, pp. 183-184) (Phillips, 1997a, p. 13) (Phillips, 1998a, pp. 4, 20). Hand augering revealed a structural depression, six feet deep, in the caliche surface (Phillips, 1987, Figure 65, Exhibit 25). Gleyed sediments were observed in trench exposures, indicating that the depression had been ponded in the past, when perched water accumulated in the depression. The caliche is extremely leached and degraded, leaving only remnants pockmarked with solution features (Phillips, 1987, Plates 18-21) [Exhibits 26 and 27]. Photographs of core reveal that the Santa Rosa sandstone at WIPP-14 is leached, broken and crumbled, presenting no barrier to rainwater infiltration (Boxes 1-6, Cores 1-26) [Exhibits 28-33].

Direct Testimony: Exhibit 28

Resistivity Survey
It comes with poor grace for DOE to mention the resistivity survey (Elliot Geophysical Company, An Experimental Detailed Resistivity Survey of Known or Suspected Breccia Pipes and Sinkholes, Eddy County, New Mexico, 12/22/76). Completed in 1976, the resistivity survey has never been published. It is not available in the public reading rooms, was not provided to the EPA, and even now government attorneys are attempting to strike it from the record in the Federal Court of Appeals in Washington, D.C.

The resistivity survey included 9880 measurement stations and 391 line miles of resistivity profiles that thoroughly covered the WIPP site. The resistivity survey was transmitted in triplicate to George B. Griswold on December 22, 1976. A follow-up report was transmitted in triplicate to Dennis W. Powers on December 29, 1977, together with eleven maps and resistivity profiles without which the text is of little use. CARD was unaware of them until they were referenced in the CCA (pp. DEF-40, DEF-41). On December 24, 1997, CARD submitted a formal request to Sandia National Laboratories asking for the reports and maps. On January 12, 1998, we were informed by Sandia that: (1) the original study is available in the Sandia central files; (2) the follow-up study is available in the public reading rooms; and (3) the maps and resistivity profiles are not available. CARD has since obtained the maps and resistivity profiles from other sources. Ironically, we have received two inquiries from DOE contractors wanting to obtain them from us (Phillips, 1998b, pp. 5-6).

Santa Rosa Sandstone
DOE states in its RCRA application that “little or no water” was encountered in the Santa Rosa sandstone, and that eleven of twelve observation wells completed in the Santa Rosa were dry (Appendix E.1, p. E1-23). To the contrary, Dr. Lokesh Chaturvedi has testified orally and in writing at these hearings that the Santa Rosa sandstone produces water in the WIPP exhaust shaft, at three boreholes drilled in 1996 within 215 feet of the exhaust shaft, and in eleven of twelve monitoring wells located within the fenced area (DOE/WIPP 97-2219, p. 23) (DOE/WIPP 97-2278, p. 69). CARD has reviewed the same reports and hereby incorporates by reference the written statement submitted by Dr. Chaturvedi at these hearings on March 2, 1999, insofar as it pertains to the Santa Rosa sandstone and the Dewey Lake Redbeds (pp. 8-10), with a single correction, that the water-saturated horizon in the WIPP exhaust shaft is in the range of 20 to 70 feet below the surface. CARD also requests that the videotape shown by Dr. Chaturvedi at these hearings on March 2, 1999, showing groundwater flowing into the WIPP exhaust shaft from the Santa Rosa sandstone and the Dewey Lake Redbeds, be entered into the record.

Dr. Chaturvedi notes that additional boreholes would be necessary to define the areal extent of the water within the Santa Rosa sandstone. Because the Santa Rosa pinches out south and west of the WIPP shafts, such boreholes would have to be drilled to the northeast. There is evidence of fluid-bearing properties in the Santa Rosa to the northeast of the WIPP shafts. In 1974 there was lost circulation of drilling fluids in the Santa Rosa sandstone at test well AEC-7, located 3.8 miles northeast of the WIPP site, at a depth of 84 feet below the surface. The well was subsequently completed to the Rustler-Salado contact (USGS memo, G. A. Dinwiddie to W. S. Twenhofel, 07/10/74), and now is cased to the Culebra dolomite (Phillips, 1998a, Table 1). In May 1978 water was found in the Santa Rosa sandstone at test well H-5c, in the northeastern corner of the WIPP site, at a depth of 220 to 225 feet below the surface. The well was subsequently completed to the Rustler-Salado contact (USGS memo, Jerry W. Mercer to William P. Armstrong, 07/07/78). In November 1979 the USGS proposed to drill another test well at the H-5 hydropad in order to evaluate the Santa Rosa for fluid-bearing properties (USGS memo, W. S. Twenhofel to William P. Armstrong, 11/09/79). The testing was never done.

DOE states that groundwater in the Santa Rosa is “isolated and discontinuous,” and “perched or semiperched” (Comment No. 273.X.5, p. 21). EEG personnel disagree with this statement, finding that a continuously sloping water table can be mapped in the Santa Rosa and upper Dewey Lake (cross-examination of Lokesh Chaturvedi at RCRA hearings, 03/04/99). There is not enough data to say definitively where the groundwater is perched and where it is not, or to model the Santa Rosa as a potential migration pathway. (Id.)

DOE reports an hydraulic conductivity ranging from 0.44 ft/day to 15.5 ft/day at the three boreholes nearest the exhaust shaft (DOE/WIPP 97-2278, p. 1). The highest reported hydraulic conductivity in the Culebra dolomite within the WIPP site is 3.8 ft/day at H-6 (Phillips, 1998a, Table 1). Thus it cannot be stated unequivocally that the Culebra dolomite is the most transmissive hydrologic unit above the WIPP repository (cross-examination of Lokesh Chaturvedi at RCRA hearings, 03/04/99), DOE's statements to the contrary notwithstanding (Comment No. 273.X.A.7, p. 23).

It is interesting that DOE states that the Santa Rosa sandstone “is less than two feet thick” (Comment No. 273.X.5, p. 21). This is illustrative of DOE's lack of understanding of WIPP site geology. The Santa Rosa is 16 feet thick at the WIPP exhaust shaft, 100 feet thick at AEC-7, and 217 feet thick at H-5c.