Area 5 Site Characterization Project: Report of hydraulic property analysis through August 1993

Abstract

Table 2. Standard methods in use by the DRI Water Analysis Laboratory (Rcno, NV). Parameter Standard Method i i pH EPA-600/4-79-020, Method 150.1 Specific Conductance EPA-600/4-79-020, Method 120.1 Alkalinity USGS, Method 1-2030-85 Chloride EPA-600/4-79-020, Method 325.1 Sulfate EPA-600/4-84-O17, Method 300.0 Sodium EPA-600/4-79-020, Method 273.1 Potassium EPA-600/4-79-020, Method 258.1 Calcium EPA-600/4-79-020, Method 215.1 Magnesium EPA-600/4-79-020, Method 242.1 Silica USGS, Method 1-2700-85 Bromide EPA-600/4-84-O 17, Method 300.0 Nitrate and Nitrite EPA-600/4-79-020, Method 353.2 I I Water Content Analysis Water content on weight and volume basis was determined for Pilot Well and Science Trench boreholes. Data are presented in Appendix A. Water content profiles from the three Pilot WeUsillustrate that water content values are very low and do not change much through the unsaturated zone. There is only a slight increase in water content with depth and a very significant increase, as would be expected, near the water table (Figures 3 and 4). Ploaed vertical profiles from the Science Trench boreholes indicate that water content values are also very low and constant throughout the approximately 120 ft of alluvium penetrated. The only noticeable trend is a slight increase in water content with depth (Figures 5 and 6). Soil Bulk Density Bulk density is an input parameter for numerical simulations of fluid, heat, and solid transport. Bulk density data arepresented in Appendix A. Plots of bulk density vs. depth forthe Science Trench boreholes (Figure 7) show no consistent trend within or between boreholes except for a slight increase in bulk density with depth in the upper 20 ft of each borehole. This increase may be a sampling artifact. No consistent trend in bulk density with depth was identified in the Pilot Well boreholes (Figure 8). Soil Water Potential Depth profiles of water potential data from the Pilot WeUs and the Science Trench bo,'eholes are summarized in Appendix A. Physical and hydrologic data for Ue5PW-2, Ue5PW-2A, Ue5PW-2B and Ue5PW-2C. Depth Total Gfrav. Bulk Vol. Water Sample Borehole Interval Potential Water Density Water Potential ID No. fit) CX-2 (KPa) Content (gr/cm3) Content Filter P. (IGUa)

Deep arid system hydrodynamics 2. Application to paleohydrologic reconstruction using vadose zone profiles from the northern Mojave Desert

“…Temperature profiles measured in the PW series wells indicate a local geothermal gradient of 11–14°C km −1 , which fall on the low end of the range of measured geothermal gradients in the Great Basin [ Davisson et al , 1994; Blankennagel and Weir , 1973]. Hydraulic property analyses completed on samples from the 3 boreholes (PW‐1, PW‐2, and PW‐3) that penetrated the entire vadose zone include gravimetric water content, water potential, bulk density, saturated hydraulic conductivity, water retention, porosity and grain size distribution [ Estrella et al , 1993; REECo , 1994]. Table 1 provides a summary of the measured site characteristics, soil properties and hydraulic parameters.…”

“…Thus matric potential and water potential are used interchangeably in this discussion. Chloride concentrations were obtained from Estrella et al [1993]. Only data from core samples, as opposed to cuttings, are used in this paper.…”

“…The wells are positioned on the apexes of an equilateral triangle, separated from each other by approximately 1.6 km. PW‐1 and PW‐2 are positioned on a relatively old pediment surface, whereas PW‐3 was drilled further up on an alluvial fan [ Estrella et al , 1993]. The UE6 wells are in Yucca Flat.…”

Fate and transport processes controlling the migration of hazardous and radioactive materials from the Area 5 Radioactive Waste Management Site (RWMS)

“…The values reported in Table 3 used groundwater to prepare the equilibrating solution, which may directly affect the experimental results. Estrella et al, (1993) reported that the ionic strength of the soil solution is much higher than that of the groundwater at Area 5. An increase in ionic strength decreases the thickness of the diffuse double layer ((DDL) -distance over which the solution concentration is affected by the colloid charge), which in turn can affect adsorption.…”

“…At low water content, sorption sites of the inorganic surfaces can effectively sorb organic compounds, however, at high water content, sorption of organic compounds is controlled by soil organic matter. Adsorption of a number of organic and volatile organic compounds (VOCs) has been found to be greater as soil moisture decreases (Hance, 1977;Bailey and White, 1964;Yaron and Saltzman, 1977;Estrella et al, 1993;Steinberg and Kreamer, 1993). Studies have shown that soil water content drastically inhibits vapor-phase sorption given that the solubility of the tested gas in water is low.…”