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KOT Environmental Consulting Inc. (KOT-ECI) has developed a cost-effective procedure to rapidly define the structure and characteristics of shallow groundwater systems. We use an engineering/statistical approach to convert all available stratigraphic descriptions to equivalent numerical values. Use of numerical values allows us to quickly isolate required data using geographic information system (GIS) techniques. Using numerical values also facilitates the preparation of maps describing the system; providing analysis of the system’s characteristics.
The key to the procedure is developing a database of all available stratigraphic information. The schematic below outlines the development steps.
KOT Environmental Consulting Inc. (KOT-ECI) Stratigraphic data from all possible sources (see schematic) is collected for inclusion in the database. We feel that all data are good, some are better than others. All collected data are not used at the same time, but the bulk of the data will have been used before the end of the project has been reached.
Collected data needs to be in an electronic format so that GIS techniques can readily be used to manipulate the data. It is not rare that some or all of the available data are not available in electronic form. When this occurs, the first step in developing the database is to convert the data to an electronic format.
When the data are in an electronic format, the information is queried using GIS to identify all the unique descriptions. These descriptions are further manipulated to remove all extraneous descriptors resulting in basic description in terms of clay, silt, sand etc. and associated proportional language.
Once the descriptions have been simplified, each description is assigned a numerical value. Hydraulic conductivity is the ability of geological materials to transmit water. The assigned numerical values represent the average hydraulic conductivity of the material described. Depending on the assigned numerical value, each description is assigned to a unit. These units are: aquifer (high conductivity), aquitard (low conductivity), and aquiclude (little or no conductivity.
An example of how well log information is converted to unit descriptions is presented below and an example of a typical completed database is presented below that.
Example of Conversion of Well Log Descriptions to Unit Descriptions
Example of a Portion of a Completed Database
