Kansas Geological Survey, Open-file Report 2011-4
Part of the Ogallala-High Plains Aquifer Project
by
R. Stotler, J.J. Butler, Jr., R.W. Buddemeier, G.C. Bohling,
S. Comba, W. Jin, E. Reboulet, D.O. Whittemore, and B.B. Wilson
with contributions by J. Munson and D. Means
KGS Open File Report 2011-4
March 2011
The calibration monitoring (index) well program is a pilot study to develop improved approaches for measuring and interpreting hydrologic responses at the local (section to township) scale in the Ogallala-High Plains aquifer (henceforth, High Plains aquifer). The study is supported by the Kansas Water Office (KWO) with Water Plan funding as a result of KWO's interest in and responsibility for long-term planning of groundwater resources in western Kansas. The Kansas Department of Agriculture, Division of Water Resources (KDA-DWR), is providing assistance, in terms of personnel and equipment, as are Groundwater Management Districts (GMDs) 1, 3, and 4.
A major focus of the program is the development of criteria or methods to evaluate the effectiveness of management strategies at the sub-unit (e.g., township) scale. Changes in water level--or the rate at which the water level is changing--are considered the most direct and unequivocal measure of the impact of management strategies. Because of the economic, social, and environmental importance of water in western Kansas, the effects of any modifications in patterns of water use need to be evaluated promptly and accurately. The project has focused on identifying and reducing the uncertainties and inaccuracies in estimates of year-to-year changes in water level, so that the impacts of management decisions can be assessed as rapidly as possible. The approach outlined by this study aims to provide more accurate and timely information at the sub-unit scale than is provided by the annual water-level measurement program. Furthermore, this study provides data that are valuable for the interpretation (or calibration) of the water-level change estimates from the annual measurement program.
At the end of year four of the study, monitoring data from three full recovery and pumping seasons and the start of a fourth recovery season have been obtained. With increasing data, the index well program has demonstrated that (1) the annual water-level measurement network (even with additional semi-annual observations) does not currently produce an adequate dataset to evaluate how management decisions affect water-level changes in the short term (fewer than five years); (2) because of uncertainties in both the effects of barometric pressure changes and the degree of well recovery at the time of the annual water-level measurement program, the data from the index wells provide the context needed for the interpretation of the results of the annual measurement program; (3) additional measurements at nearby [local (~township) scale] wells are needed through most of a recovery season to establish the representative area (areal reach) of an index well; (4) with a complete recovery record, it appears possible to extrapolate to fully recovered water levels; (5) local hydrogeologic variations and well construction need to be assessed and considered in the interpretation of well hydrographs; these factors may complicate use of wells of opportunity as index wells; and (6) water-level data collected using a pressure transducer and data logger provide a near-continuous water-level record that can help in the estimation of changes in the amount of extractable water and in assessing the uncertainty in those estimates.
This report will provide (a) an update of the hydrographs for the three index wells; (b) a detailed look at methods to estimate the elevation to which the water level would rise at full recovery in each of the index wells; (c) comparisons of the annual water-level changes measured at the index wells with those from nearby wells to assess the representative area sampled by the index wells; (d) interpretation of hydrographs from the index wells and the wells in the expanded monitoring areas in the vicinity of two of the index wells; and (e) an overview of the KGS barometric correction spreadsheet program, which calculates the barometric response function for a given well and corrects the measured water levels for the impact of barometric pressure changes.
Read the PDF version (8.2 MB, rev. April 5, 2011)
Kansas Geological Survey, Geohydrology
Placed online March 31, 2011
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