Thursday, January 7, 2010

Voss comments on Sutra and its application in the Shenandoah Valley

Cliff wrote me last night and gave me permission to share his e-mail on the blog. Click the comment below. The USGS wrote cool structural geology solid modeling tools for the Shenandoah Valley project. This underscores that solid modeling is a significant research topic in and of itself. Many of the codes that handle these problems are understandably proprietary, but the result is that they are a bit black-box to the research community.
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1 comment:

  1. John R. Hoaglund, III, Ph.D.January 7, 2010 at 12:18 PM

    Hi John

    We did some interesting work to model 3D anisotropy. Have you seen the article by Yager, Voss and Southworth in Hydrogeology Journal?
    http://www.springerlink.com/content/42527x186nr51794/?p=47e6392ffcb64318966824247bfe6d47&pi=1

    [abstract in P.S. below]

    Our ArgusONE SutraGUI has some software for specifying structure in cross sections that the GUI turns into a 3D pattern.

    […]

    Dick Yager has subsequently used Sutra to model the Newark Basin - but the anisotropy there is simpler than in the Shenandoah Valley. I am not sure that the report is finished, but you can contact him ryager@usgs.gov if you are interested.

    Good wishes!
    Cliff
    [ P.S. ]
    Comparison of alternative representations of hydraulic-conductivity anisotropy in folded fractured-sedimentary rock: modeling groundwater flow in the Shenandoah Valley (USA)
    Richard M. Yager1 , Clifford I. Voss2 and Scott Southworth2
    (1) US Geological Survey, 30 Brown Road, Ithaca, NY 14850, USA
    (2) US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192, USA
    Received: 7 September 2007 Accepted: 27 December 2008 Published online: 25 January 2009 (Hydrogeology Journal)
    Abstract A numerical representation that explicitly represents the generalized three-dimensional anisotropy of folded fractured-sedimentary rocks in a groundwater model best reproduces the salient features of the flow system in the Shenandoah Valley, USA. This conclusion results from a comparison of four alternative representations of anisotropy in which the hydraulic-conductivity tensor represents the bedrock structure as (model A) anisotropic with variable strikes and dips, (model B) horizontally anisotropic with a uniform strike, (model C) horizontally anisotropic with variable strikes, and (model D) isotropic. Simulations using the US Geological Survey groundwater flow and transport model SUTRA are based on a representation of hydraulic conductivity that conforms to bedding planes in a three-dimensional structural model of the valley that duplicates the pattern of folded sedimentary rocks. In the most general representation, (model A), the directions of maximum and medium hydraulic conductivity conform to the strike and dip of bedding, respectively, while the minimum hydraulic-conductivity direction is perpendicular to bedding. Model A produced a physically realistic flow system that reflects the underlying bedrock structure, with a flow field that is significantly different from those produced by the other three models.
    Keywords USA - Fractured rocks - Numerical modeling - Bedrock structure - Anisotropy


    .....................................................................................................
    C l i f f o r d I . V o s s
    Research Hydrologist - National Research Program
    U.S. Geological Survey
    431 National Center
    Reston, VA 20192 USA
    Telephone: 703-648-5885
    Telefax: 703-648-5274
    Email: cvoss@usgs.gov
    .....................................................................................................
    Executive Editor * * * Hydrogeology Journal
    International Association of Hydrogeologists - IAH
    .....................................................................................................

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