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2000 Annual Water Level Raw Data Report for Kansas

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Executive Summary

The Division of Water Resources (DWR) of the Kansas Department of Agriculture and the Kansas Geological Survey (KGS) manage and operate the statewide cooperative annual water level measurement program. Water level measurements are scheduled annually for about 1,400 wells spread across 51 central and western Kansas counties (Figure 1). These annual measurements are nominally made during the month of January and include wells used for stock, irrigation, household, and monitoring (some abandoned agricultural or domestic wells). The data acquired during these yearly measurements are tabulated to establish trends and allow evaluation and judgments for effective water resource management.

Figure 1--Locations of wells in 2000 water-level measurement program.

map of Kansas showing annually measured wells

The KGS and DWR share responsibility for acquiring annual water levels. The KGS measures 555 wells in 19 counties while DWR has responsibility for 810 wells in 32 counties (two counties are shared) (Figure 2). Most wells in the network (73.0%) are currently used for irrigation. During 2000, 95.3% of all annual network wells were successfully measured. Approximately half of these measurements (47.3%) encountered water at depths of less than 100 ft. About 1.3% of network wells have depths to water greater than 300 ft. At the present time 638 of the 1,365 annual network wells have GPS-measured latitudes and longitudes. After completion of the 2000 measurement season, 35 network wells have been targeted for retirement due to plugging, surface or downhole obstructions, inaccessibility to the water surface as a result of changes in measurement point, destruction, or "dry hole." Attempts over the last two years to fill holes in the network represent the first increase in the High Plains AquiferÕs annual well inventory since the middle 1980s. Reduction of the sampling holes by the yearly incorporation of enhancement wells will be an ongoing process that will be based on number and location of wells retired from the network each year. Digital and analog 2000 annual raw water level data were available for widespread distribution around March 1, 2000.

Figure 2--Number and organizational responsibility by county for the 2000 network wells.

map of Kansas showing how many wells are measured in each county

Data acquisition enhancements evaluated or refined during the 1999 campaign were incorporated into the 2000 KGS program, and DWR changes include the initial use of computers running the Water Witch software for several hydrographers. The most significant enhancement for KGS was the inclusion of a seventh person functioning as a troubleshooter and enhancement/replacement well investigator. The seventh person operated alone, following the three two-man crews doing re-measurements of wells that were out of trend as well as locating and measuring wells previously selected as candidate enhancement or replacement wells. Use of the KGS-developed, computerized data acquisition system (WaterWitch) permitted on-site entry of measurements and comments, automated checks of data quality, optimized routing, and the encryption of a location stamp on each measurement. Improved routing and the computerized acquisition system reduced data acquisition time from 8 days (1997) to 6.5 (1998) and then to 5.5 (1999 and 2000) for the three, two-person crews. Improvements in training/technique and routing increased the 13 wells/person/day measured in 1998 to over 16 wells/person/day measured in 2000. Insight gained through statistical analyses of the 10% re-measurement wells (QA) continued in 2000 to prove invaluable in both improving our product and in determining the overall quality of the measurement data. Re-visits and re-measurement of wells classified as out-of-trend during initial measurements (QC) improved confidence and minimized measurement errors in the database.

Data acquisition enhancements evaluated during the 2000 campaign include the introduction of the Warlock. This is a paperless data entry system centered around a small (3"x5"x_") handheld computer, the Palm Pilot-III, running custom in-house software. Initial results show this system to be an extremely effective and a highly efficient data acquisition/ recording tool.

Spatial analysis of the 1999 water level data identified 32 locations where new wells should be incorporated into the annual measurement network to eliminate sampling "holes." Cooperation between the groundwater management districts (GMDs), DWR, and KGS staff identified wells acceptable for inclusion in the network at 16 of the 32 locations. Even though only 12 of the 32 sites actually resulted in water level measurements, a procedure is developing for the incorporation of new wells into the annual network while the overall completeness of sampling continues to improve. The last three years have seen positive growth in the number of wells in the annual network in response the retirement or replacement of inconsistent, plugged, or inaccessible wells.

The Quality Control program continues to achieve its objectives of identifying and quantifying sources of unwanted variation in observation well data collection, and in flagging wells whose measurements require verification. In 2000, most of the possible sources of unwanted variation were not significant, in strong contrast with results obtained in 1999 when most exogenous variables were significant. The variance in water level change in 2000 is about one-third its value in 1999, probably because 24 wells whose measurements were atypical and likely in error were deleted from the network. These 24 wells had made excessive contributions to the total variance and were responsible for most of the statistical significance attributable to exogenous variables. The wells had been repeatedly measured, indicating that measurers either had difficulty obtaining reliable readings or that initial depths to water were significantly out-of-trend. As the Quality Control process continues to be applied to the KGS observation well measurement program in the future, similar improvements in data quality are to be expected.

The original observation well network designed in 1984 was based on a regular hexagonal pattern, with observation wells located at or near the centers of the hexagons. Unfortunately, some current observation wells are far from the centers of their hexagons, and some hexagons no longer contain a network well at all, resulting in "holes" in the network. The integrity of the network is being restored through the selection and measurement of new wells optimally located to fill existing undersampled areas. Determining the very best places for replacement wells requires a geostatistical study, which unfortunately delays the measurement of the water surface in undersampled areas. Replacement wells selected by measurement staff during the measurement campaign are preferred over leaving a "hole" in the network for that measurement year while waiting for a computer-aided replacement well to be selected for the following year. A good rule of thumb for field workers to use for selecting a replacement for a lost observation well is to choose a new well as close as possible to the center of the hexagon. It is possible to have holes form in the network if replacement wells deviate too far from the center of the hexagon. Yearly geostatistical studies will define undersampled areas (holes) and select optimum locations for replacement wells to eliminate extraneous holes in the network occasionally left by the hexagon system.

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Kansas Geological Survey, Water Level CD-ROM
Send comments and/or suggestions to webadmin@kgs.ku.edu
Updated March 9, 2000
Available online at URL = http://www.kgs.ku.edu/Magellan/WaterLevels/CD/Reports/OFR0010/rep01.htm