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User's manual for the particle tracking model ZOOPT

By C.R. Jackson


This report describes the development of a steady-state particle tracking code for use in\ud conjunction with the object-oriented groundwater flow model, ZOOMQ3D (Jackson and\ud Spink, 2004). Like the flow model, the particle tracking software, ZOOPT, is written using an\ud object-oriented approach to promote its extensibility and flexibility.\ud ZOOPT enables the definition of steady-state and time-variant path lines in three dimensions.\ud Particles can be tracked in both the forward and reverse directions in steady-state flow fields\ud enabling the rapid definition of borehole catchments, recharge and discharge areas and the\ud visualisation of groundwater flow fields, for example. The program also enables the\ud visualisation of steady-state particle tracks that are based on the node-by-node flows at a specific\ud instant of a time-variant simulation. For example, this capability allows the examination of the\ud changing shape of an approximate borehole catchment over an annual recharge or abstraction\ud cycle. Particles can currently only be tracked in the forward direction in dynamic, or timevariant,\ud flow fields.\ud Path lines are defined using the semi-analytical method (Pollock, 1988), however, around\ud particular model features the Runge-Kutta technique is implemented in order to solve some\ud specific problems associated with particle tracking. The problem of particle termination at\ud ‘weak’ sink nodes is solved by the application of the special velocity interpolation scheme\ud presented by Zheng (1994). This approach enables the definition of borehole catchments around\ud wells that induce weak sinks which is not possible with many other widely used particle tracking\ud codes.\ud ZOOMQ3D incorporates the representation of the vertical variation of hydraulic conductivity\ud with depth (VKD) within finite difference nodes. This has been implemented in the flow model\ud to enable the more accurate description of the variation of hydraulic conductivity in limestone,\ud and particularly Chalk aquifers. ZOOPT is fully compatible with VKD models.\ud ZOOMQ3D also enables the local refinement of the finite difference grid, for example, around\ud pumping wells. Again, ZOOPT is fully compatible with this model feature and can be used to\ud track particles through such refined meshes.\ud ZOOPT has been rigorously tested through its comparison with an analytical solution and\ud another particle tracking code and through the inspection of path lines generated using numerous\ud test models (Jackson, 2002b)

Publisher: British Geological Survey
Year: 2004
OAI identifier:

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  2. (1994). A semi-analytical method of path line computation for transient finite-difference groundwater flow models.
  3. (1994). Analysis of particle tracking errors associated with spatial discretisation. doi
  4. (1995). Applied contaminant transport modelling. Van Nostrand Reinhold,
  5. (1978). Computer model of two-dimensional solute transport and dispersion in ground water.
  6. (1989). Documentation of computer programs to compute and display path lines using results from the U.S. Geological Survey modular three-dimensional finite-difference ground-water model.
  7. (1990). FLOWPATH, two-dimensional horizontal aquifer simulation model. Waterloo Hydrogeologic Software,
  8. (1987). GWPATH: interactive ground-water flow path analysis. Bulletin 69, Illinois State Water Survey,
  9. (1990). MT3D: A modular three-dimensional transport model for simulation of advection, dispersion and chemical reactions of contaminants in groundwater systems. Report to the U.S. E.P.A.,
  10. (1990). Particle velocity interpolation in block-centred finite difference groundwater flow models.
  11. (1989). PATH3D, a groundwater path and travel-time simulator, version 3.0 user’s manual.
  12. (1988). Semianalytical computation of path lines for finite-difference models. doi
  13. Steady-state particle tracking in the object-oriented regional groundwater model ZOOMQ3D. British Geological Survey Commissioned Report CR/02/210N. Environment Agency
  14. (2001). The development and validation the object-oriented quasi three-dimensional regional groundwater model ZOOMQ3D. British Geological Survey Internal Report IR/01/144.
  15. (2002). The representation of the variation of hydraulic conductivity with depth in the objectoriented regional groundwater model ZOOMQ3D. British Geological Survey Commissioned Report CR/02/152N. Environment Agency
  16. (1995). Theory and practice of contaminant transport modelling using the random walk. Unpublished Ph.D. Thesis,
  17. (2004). User’s manual for the groundwater flow model ZOOMQ3D. British Geological Survey Internal Report IR/04/140.
  18. (1991). WHPA: A modular semi-analytical model for the delineation of wellhead protection areas, version 2.0. Report to the U.S. Environmental Protection Agency,

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