Site Characterization and Visualization
The first phase of a groundwater modeling project usually begins with site characterization. The Borehole, TIN and Solids modules within GMS provide tools for modeling the three dimensional stratigraphy of a region. These tools are used independently in GMS to create subsurface site visualization. These tools can also be used in GMS as the basis for creating grids or meshes for numerical groundwater models.
GMS provides modeling tools that have been designed specifically for defining surfaces and solids of geologic origin. The program will accept field data in the form of borehole logs and allow the user to process the data to directly define a solid model.
Boreholes
Data from borehole logs can be read into GMS. Two types of borehole data are supported: stratigraphy data and sample data.
Boreholes with stratigraphy data
Boreholes with sample data
Borehole Cross Sections
User defined cross sections can be constructed between boreholes. This is a quick and easy way for users to create fence diagrams. Also, the cross sections can be used to guide the creation of solids using the Horizons to Solids method.
Horizons
The term "horizon" refers to the top of each stratigraphic unit that will be represented in the solid, HUF unit, or 3D Mesh. Horizons are numbered consecutively in the order that the strata are "deposited" (from the bottom up). Horizons are defined at borehole contacts or on TINs. First, the user assigns horizon ids; then, the user can create 3D stratigraphy models.
TINs
The Triangulated Irregular Network (TIN) module is used for surface modeling. TINs are formed by connecting a set of XYZ points (scattered or gridded) with edges to form a network of triangles. The surface is assumed to vary in a linear fashion across each triangle. TINs can be used to represent the surface of a geologic unit or the surface defined by a mathematical function.
Several TINs can be modeled at once in GMS. A TIN may be created within GMS by several methods or can be imported from other systems. TINs can be used in GMS to build solid models and 3D meshes or they can be converted to other types of data such as scatter points for interpolation to grids.
Solids
The Solid module of GMS is used to construct three-dimensional volumes called "solids". Once a solid is created, cross sections can be cut anywhere on the model and the solids can be shaded to generate realistic images. Solids can be created from TIN surfaces or using the "Horizons Method" for creating solids quickly and accurately.
Cross Sections and Fence Diagrams
Once a solid is created, cross-sections and fence diagrams can be cut to visualize the subsurface and illustrate complex stratigraphic relationships.
