Secondary porosity in a transient vadose zone

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5811829

Frederick, W T; Grasso, Jr, T X ^[1]

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1. Dames and Moore, West Valley, NY (United States)

The Western New York Nuclear Service Center is the site of low and high level radioactive waster buried in a series of trenches excavated in a 28 m thick, Lavery-age silty clay diamicton that exhibits a 6 meter thick transient vadoes zone where exposed at the surface. Hydrostratigraphy of this till includes a 0.25 m thick poorly developed macroporous soil, a 3.5 m thick weathered zone of densely spaced and randomly orientated horizontal and vertical fractures, a 2 m thick unweathered zone of intermittently spaced fractures exhibiting east-west orientations, and a massive 23 m thick unweathered till zone that exhibits isolated, east-west orientated fractures. Bulk hydraulic conductivity of this active flow zone decreases with depth from 10[sup [minus]5] to 10[sup [minus]8] cm/s. The specific discharge of vertically flowing groundwater in the massive till zone is 1.25 cm/yr. A water surplus in the recharge season saturates the fractured zone to grade with up to 7.37 cm/yr of net infiltration. Tritium and radionuclides from the waste trenches and surrounding soil matrix hydrodynamically disperse into the field-saturated fracture network that contains meteoric recharge water. A soil moisture deficit in discharge season produces a vadose zone of widened fractures that via capillarity enhances the diffusion of contaminants into the soil matrix. These enlarged connecting conduits laterally channel the excess infiltration from the recharge season and diffused contaminants to local lowlands and incised streams that truncate the unweathered till. The current vadose and phreatic zone flow study will be used in numeric simulations that will delineate the areal extend and temporal duration of these seepage faces and the time frame of possible surfaces water contamination.

• OSTI ID: 5811829
• Report Number(s): CONF-9303211--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

Related Subjects

052002* -- Nuclear Fuels-- Waste Disposal & Storage
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
540230 -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- (1990-)
58 GEOSCIENCES
580000 -- Geosciences
DEVELOPED COUNTRIES
FLOW MODELS
GEOLOGIC DEPOSITS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GROUND WATER
HYDRAULIC CONDUCTIVITY
HYDROGEN COMPOUNDS
HYDROLOGY
MANAGEMENT
MATHEMATICAL MODELS
MORAINES
NEW YORK
NORTH AMERICA
NUCLEAR FACILITIES
OXYGEN COMPOUNDS
PERMEABILITY
POROSITY
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE FACILITIES
RADIOACTIVE WASTE MANAGEMENT
SITE CHARACTERIZATION
USA
WASTE DISPOSAL
WASTE MANAGEMENT
WATER