Kansas Geological Survey, Open-File Rept. 91-1
Annual Report, FY91--Page 8 of 8
The hydrologic data from FY89 were combined with additional data compiled in FY90 and FY91 and the master data set imported to INFO. Because water-level data have a temporal component (i.e., multiple samples for the same point over time), the water-level data base was designed to support one-to-many operations. ARC/INFO does not presently support one-to-many relate operations; an alternative data set structure is being employed that permits this functionality.
The two data sets are parts of a larger well data base being developed for the Dakota Aquifer Program. The data base is a subset of the USGS's Ground Water Site Inventory (GWSI) well data base and is designed to facilitate data interchange between the two data bases. The geohydrology data base consists of individual INFO data sets for general well information, geology, and water levels (Tables 5-7) and is designed around an ARC/INFO point coverage identifying each individual well in the data base. This design will enable the implementation of a "point and click" interface. Users will be able to interactively select wells from a map on the screen and display data about a selected well.
The ability to pass data to and from the ground-water flow model used in the Dakota Aquifer program will be implemented by an interface between the GIS and MODFLOW. This interface will allow MODFLOW to read data sets maintained in ARC/INFO and will allow output from MODFLOW to be placed in the INFO data sets. This increases the usefulness of the GIS as a data preprocessor access to large data sets. The GIS will also serve as a postprocessor for the creation of maps and tabular output from the ground-water flow model. The interface is written primarily in the INFO programming language and has two machine-dependent subprograms that must be customized for use on the KGS Data General minicomputer.
A data base containing information on percentage of sand in the Dakota aquifer is also being compiled from digitized well logs using the statistical package SAS. Individual well logs are segmented by using picks from the geologic data base delineating formation tops. The logs are analyzed to discriminate between sands and shales. Output from SAS consists of an ASCII data set listing total feet of sand and percentage of sand in each unit of the formation. The data is then imported to ARC/INFO and used to create contour maps showing these features (see Figures 8 and 9).
The primary emphasis during the latter part of this four-year period (FY92-94) is (1) to integrate the findings from previous years' research and (2) to develop three-dimensional digital models of the Dakota and adjacent aquifers in southeastern Colorado and southwestern and central Kansas that can be used to simulate in phases the flow of water, transport of solutes, and chemical reactions along the flow path. These simulations can be useful for testing hypotheses about the nature of the flow system in the Dakota aquifer, for determining rates of interchange between aquifers, and for assessing the effects of pumping on water availability and quality. Development and the use of quasi-three-dimensional models to simulate the hydrology will be carried out in phases. In FY94 the program emphasis will shift to the simulation of water resources management options in the area of the Dakota aquifer currently under development. In phase 1 (FY92) computer models of the ground-water flow system will be used to determine the factors controlling the ground-water flow system (such as the arrangement of aquifer and aquitard units), and the effect of topography and to estimate the amount of recharge to and discharge from the aquifer.
Completion of these objectives is required for the development of a three-dimensional model that can be used to simulate temporal changes in ground-water flow resulting from pumping or injection and mass transport. The objective of the FY93 Dakota Aquifer Program (phase 2) will be to continue using models of the Dakota to assess the effects of pumpage or injection on water quality in the Dakota aquifer. These models will be used to assess the effect of various water management scenarios in FY94 (phase 3).
Late in FY94 the research direction of the program will begin to shift to the deeper subsurface of northwest Kansas. In this area readily available data are sparse and the depth to the top of the Dakota aquifer is considerable. As a result, most of the program's attention will be focused on those areas adjacent to the area under present development, especially in Greeley, Hamilton, Kearny, Wichita, Scott, and Lane counties in southwest Kansas and in Jewell, Smith, and Phillips counties in northern Kansas. Concerns in northwest Kansas are primarily related to the quality of ground water in the Dakota aquifer. To address these concerns, we will emphasize data collection from monitoring sites constructed in the Dakota aquifer and the performance of drill stem tests on the aquifer in this area and from the use of other appropriate technologies. A preliminary analysis in FY89 indicated considerable potential for water resources development in parts or all of Lane, Scott, Wichita, and Gove counties.
In the geologic framework part of the program the activities included: (1) expansion of the geophysical log data base in south-central and southwestern Kansas, (2) expansion of the southwestern and south-central Kansas geologic data base, (3) interpretation of the geophysical log data base to develop more detail on the Dakota aquifer framework (ongoing), and (4) geophysical log analysis of aquifer properties in the Dakota aquifer framework to determine aquifer units (initiated).
In the geohydrology part of the program the activities included: (1) completion of monitoring site construction in Cloud, Lincoln, and Hodgeman counties, (2) completion of hydrologic testing at the Lincoln and Cloud County sites, (3) completion of the Washington and Republic county geohydrology study, and (4) regional ground-water flow modeling of southeastern Colorado and Kansas using cross-sectional models (ongoing).
In the geochemistry part of the program the activities included: (1) collection and analysis of water samples from field surveys and pumping tests (ongoing), (2) preparation of water-quality distribution maps (initiated), (3) water-quality use assessment for water supplies (ongoing), (4) examination of the factors controlling the major constituent concentrations and water types based on the water chemistry data base (ongoing), and (5) testing and evaluation of coupled geochemical and mass transport models (initiated).
The GIS-data base management area includes (1) completion of overall data-base design composed of the water chemistry, geophysical log, geologic, and water-level data bases, (2) integration of the separate geologic and hydrologic data sets into INFO format in the geographic information system (completed), and (3) development of an interface to use ARC/INFO as a pre- and postprocessor for MODFLOW (initiated).
Finally, in the area of research support, the annual report of the FY90 Dakota Aquifer Program was completed and published as KGS Open-File Report 91-1. During the fiscal year several other reports were also published: Revised Stratigraphic Interpretation and Implications for Pre-Graneros Paleogeography from Test-Hole Drilling in Central Kansas (KGS Open-File Report 91-1A) and Determination of Aquifer E=erdes of the Dakota Aquifer in Washin Lyton County, Kansas, from a Puml2 Test (KGS Open-File Report 91-lC). KGS Open-File Report 91-lB is in the final stages of preparation.
During FY90-93 the overall objective of the Dakota Aquifer Program is to characterize subregionally the water resources potential of the areas where the Dakota aquifer is shallowest and is undergoing development in central and southwestern Kansas. The progress made during the FY91 program has provided much new information that is being used to update existing data bases and to construct three-dimensional simulations of the Dakota and hydraulically connected aquifers in southeastern Colorado and Kansas in FY92-94. In FY94 these simulations will be used to evaluate various management options for the Dakota aquifer in Kansas.