Generally the geology of the Breton area of Alberta consists of a 5‐to 125‐ft (1.5‐ to 38.1‐m) veneer of glacial till overlying sandstone and sandy shale units of the Paskapoo Formation. These sandstone units are locally important aquifers. Glacial drift in the Hastings Lake area varies in thickness from 100 to 200 ft (30.5 to 61.0 m) and overlies the Horseshoe Canyon Formation, which consists of bentonitic shale, siltstone and coal units with minor sandstone units. Ground‐water yields from drift and bedrock in this area are generally less than 30 gpm (113.6 1/m). Resistivity soundings were completed at 68 and 65 stations in the Breton and Hastings Lake areas, respectively. Profile maps from the Breton area are characterized by broad areas with apparent resistivity values greater than 100 ohm‐ft (3048 ohm‐cm). Qualitative evaluation of the resistivity soundings and existing borehole data indicated that the high resistivity values resulted from a thick resistive sandstone aquifer less than 25 ft (7.6 m) from ground surface. A reasonably well‐defined resistivity pattern was evident on the profile maps of the Hastings Lake area with the highest resistivity values coming from stations located in the hummocky moraine south of the lake. Sounding curves and borehole data indicate that an increase in the sand content of the drift is responsible for these values. However, local variability in the drift lithology produces anomalies in the resistivity patterns. In addition to providing useful information on the geology of an area, surface resistivity methods provide a rapid and relatively inexpensive tool to aid in planning more detailed ground‐water studies because of their ability to detect inhomogeneities in the subsurface environment.

No abstract

This paper demonstrates the operation of EXPAR, a knowledge‐based system designed to assist in preparing a set of data for a contaminant transport model. The accompanying evaluation exercise provides preliminary indications of the usefulness of EXPAR. The exercise tested the ability of participants to simulate the distribution of three organic compounds at a hazardous waste site near Ottawa, Canada. A modest set of basic information was provided together with one of four sets of supplementary data. The embedded knowledge in the EXPAR system appeared to provide valuable assistance in modeling, and the system itself met our expectations in terms of the user‐friendliness and robustness. Additional work will be required to remove the weaknesses found in the evaluation particularly with respect to biodégradation data and guidance in establishing flow directions. The results of the project have shown that knowledge‐based systems show promise in solving problems associated with the implementation of a transport model.

Computer software with embedded knowledge has the potential to improve the utility and usability of computer models. We explore these opportunities with the software package Expert ROKEY that includes EXPAR, a knowledge‐based system to assist in the preparation of input data for a simple mass transport model. EXPAR is partitioned into two levels. At the top level is a set of computer forms that contain groups of related parameters and corresponding entry fields. Users can either volunteer parameter values or request help from an assistance program. Elaboration programs provide supporting information for each parameter and brief tutorials for the mass transport processes included in the model. The sets of assistance and elaboration programs represent the bottom level of EXPAR. This model preprocessor contains useful features like tutorial and data‐base information, systematic procedures for deriving parameter values, capabilities for checking the completeness and consistency of data, and a virtually transparent user interface with the computer, which are applicable to codes of all types.