|
...the directional components of an arbitrary flow direction, and the intralayer distances upon which these calculations are based, may become functions of the angle of dip. Modeling these systems, where bedding and/or bedding-plane partings are known to influence ground water flow (Burton et al. 2002), requires the physical rotation with dip of the transverse anisotropy in hydraulic conductivity, and depending on the model grid, may require the rescaling of intra-aquifer distances along dip. Bedding-parallel hydraulic conductivities, [K.sub.x], are determined from the analyses of in situ aquifer tests and/or lab tests in the plane of bedding. Intralayer distances between solution points (nodes) in the model are determined in the horizontal plane, usually from maps. Typically, the modeler assigns both the bedding-parallel hydraulic conductivity and the map distances to layer within the model, assuming the principal conductivity directions in the plane of bedding, and the locations corresponding to the nodes of the grid, both lie in the horizontal plane. Bedding-orthogonal hydraulic conductivities, [K.sub.y], are determined from the analyses of in situ packer tests and/or lab tests in the plane perpendicular to bedding. Interlayer distances are commonly determined from vertical stratigraphic separations between aquifers; the vertical spacing between nodes may either be fixed or vary according to the thickness of the aquifer. Typically, the modeler assigns both the vertical stratigraphic separations and the bedding-orthogonal hydraulic conductivity to the vertical direction in the model, assuming the vertical direction corresponds to the principal conductivity direction perpendicular to the plane of bedding. However, in structural terrains at the scale of a ground water or reservoir model, the principal conductivity directions may not be aligned with the model axes and thus the directional components of an arbitrary flow direction become functions of the angle of dip, rotating the principal directions with the regional and/or local fold-controlled bedding. Depending on the choice of model grid, the intralayer distances also may become functions of the angle of dip. The typical approach then fails to characterize the flow properly within the medium and error is introduced to the model calculated heads and flows. This paper outlines corrections that can be made to ground water models to rescale intralayer distances and characterize the transverse anisotropy related to the structural dip of bedding.
Model coordinate systems commonly require solution of the...
NOTE: All illustrations and photos
have been removed from this article.
More articles from Ground Water
Using temperature to test models of flow near Yucca Mountain, Nevada., September 01, 2003
Looking for additional articles?
Search our database of over 3 million articles.
Looking for more in-depth information on this industry?
Search our complete database of Industry & Market reports by text, subject, publication
name or publication date.
About Goliath
Whether you're looking for sales prospects, competitive information, company
analysis or best practices in managing your organization,
Goliath can help you meet your business needs.
Our extensive business information databases empower business
professionals with both the breadth and depth of credible,
authoritative information they need to support their business
goals. Whether it be strategic planning, sales prospecting,
company research or defining management best practices -
Goliath is your leading source for accurate information.
|
