Ground-water hydrology and subsurface migration of radionuclides at a commercial radioactive-waste burial site, West Valley, Cattaraugus County, New York

Abstract

Test holes and wells 12 Stratigraphy and general groundwater movement at the burial site 14 Physical and hydraulic properties of the till 20 Physical and mineralogical properties 20 Hydraulic conductivity 20 Anisotropy 2 3 Fractured zone 23 Lenses of sorted material 23 Extent and continuity 23 Hydraulic conductivity 29 Equivalent hydraulic conductivity of the till 29 Groundwater flow at the burial site 30 Flow within the till 30 Flow within the underlying lacustrine unit 32 Computer simulation of groundwater flow 33 North trenches 37 Page Groundwater flow at the burial site Continued Computer simulation of groundwater flow Continued South trenches Limitations and results Seepage from trenches to nearest streams Seepage through a hypothetical permeable layer Estimated traveltime Recharge to trenches Correlation of precipitation with water-level rises in trenches Effects of additional cover over trenches 1 through 5 on water levels Infiltration of precipitation through cracks in cover Cracks caused by settling of waste Cracks caused by seasonal drying of cover Chemistry of trench water Sampling methods Composition of trench water Radionuclide migration from trenches Outward migration Downward migration-42 4*; 46 47 48 Notation for Selected Radionuclides Notation 3H HTO "C 60Co 40R 22Na 85Sr 90gr 133Ba l34Cs 137Cs 241Am 238pu 239.240pu Element Tritium (hydrogen) Tritium (hydrogen in form of water) Carbon Cobalt Potassium Sodium Strontium Strontium Barium Cesium Cesium Americium Plutonium Plutonium Atomic weights 3 3 14 60 40 22 85 90 133 134 137 241 238 239,240 ALTITUDE DATUM The term "National Geodetic Vertical Datum of 1929" (NGVD of 1929) replaces the formerly used term "mean sea level" to describe the datum for altitude measurements. NGVD of 1929 is derived from a general adjustment of the firstorder leveling networks of both the United States and Canada. For convenience in this report, the datum is referred to as sea level.

The interaction of ground water with prairie pothole wetlands in the Cottonwood Lake area, east-central North Dakota, 1979–1990

“…Hendry (1982) reported values of about 10 -5 to 10 -7 cm sec -1 for field tests of till in southern Alberta. Prudic (1986) reported hydraulic conductivity values of 10-s cm see-t for clayey till in New York, and Bradbury et al (1985) reported values of 10 -9 cm sec -j for clayey till in northern Wisconsin. Both of the latter studies were of till that has a higher clay content than the till in the north-central prairies.…”

Importance of Unsaturated Zone Flow for Simulating Recharge in a Humid Climate

“…Neglecting unsaturated zone processes is not considered appropriate in arid regions, where the thickness of the unsaturated zone can reach hundreds of meters and water recently recharged at the top of the unsaturated zone may not ever reach the water table given current climate conditions. Furthermore, there are notable examples where the unsaturated zone was explicitly included in watershed scale transient models in humid climates (Freeze 1972a, 1972b; Prudic 1981; Winter 1983; Smith and Hebbert 1983; Lee 2000; Vanderkwaak and Loague 2001; Jones et al 2006). However, when the unsaturated zone is included, these efforts commonly used a fully coupled saturated‐unsaturated flow approach based on Richards’ equation (Richards 1931; Freeze 1971; Reeves and Duguid 1975; Frind and Verge 1978; Yeh 1987; Vanderkwaak 1999; Panday and Huyakorn 2004).…”

Ground-water flow and transport modeling of the NRC-licensed waste disposal facility, West Valley, New York

“…Downward water flow rates are thus on the same order as the hydraulic conductivity of the till. Under these low flow rates diffusion becomes the dominant transport mechanism for water dissolved radionuclides (Prudic, 1986). However, an alternative pathway may exist whereby contaminants migrate laterally through the fractured, upper layer of the till.…”

“…As the disposal pits fill with water, contaminants could move upward into the upper fractured zone and from there travel laterally through this more permeable zone to nearby streams or other exposure points. A number of groundwater modeling studies of the FDA and adjacent state-licensed disposal areas have been conducted previously (Prudic, 1986;U.S. DOE, 1986;Bergeron and Bugliosi, 1988).…”