1. Kansas High Plains Aquifer: Analysis of 2005 Water Levels Geoffrey C. Bohling Brownie Wilson Geohydrology Section

2. Annual Measurement Program  High Plains Aquifer water levels measured annually by KGS and KDA-DWR since 1997  Evolved from USGS measurement program  Measured in winter (January) to minimize effects of irrigation on measurements  Designed to monitor changes and identify regional trends in water table

3. Well Locations and HPA Extent 1 well every 16 square miles Current monitoring network for HPA has 1348 wells

4. Measurement Responsibility, 2004

5. Measurement Responsibility, 2005

6. Generalized N-S Cross-section From High Plains Aquifer Atlas: http://www.kgs.ku.edu/HighPlains/atlas/

7. Data Collection: WaterWitch/WaterBug

8. GPS Site Location with WaterWitch

9. On-site Data Entry With WaterBug Water Bug

10. Wizard Database http://www.kgs.ku.edu/Magellan/WaterLevels/index.html

11. Winter 2005 Measurements  1267 wells: 715 DWR, 552 KGS  Most measurements made in Jan. 2005, but range from Dec. 2004 – Feb. 2005  Repeat measurements at 53 wells for quality control  968 irrigation wells, 233 observation wells, rest other uses

12. Statistical Quality Control  Analysis of variance to detect unwanted sources of variation in measurements Measurer, ease of access, well use, oil on water, weighted tape, chalk cut quality, aquifer group Measurer, ease of access, well use, oil on water, weighted tape, chalk cut quality, aquifer group  Use 1-year declines to factor out strong spatial correlation of measured depths  Conclusion: Aquifer group only significant source of variation (more later)

13. 2005 Water Table Elevation

14. Crossvalidation of Interpolation

15. Interpolation Error Map, 2005 WTE

16. 2004 to 2005 Declines

17. Map of 2004 to 2005 Declines

18. 1-Year Declines by Aquifer Group

19. 2000 to 2005 Declines

20. Map of 2000 to 2005 Declines

21. 1995 to 2005 Declines

22. Map of 1995 to 2005 Declines

23. Decline Rate Comparison

24. Five-Year Average Declines

25. Precipitation

26. Conclusions  Measurement program is very reliable  Average 2004 to 2005 decline (0.15 feet) significantly less than average decline rate over past five (1.09 feet/year) or ten (0.58 feet/year) years  Due at least in part to precipitation  But declines still persist, still strong in some areas

27. From High Plains Aquifer Atlas: http://www.kgs.ku.edu/HighPlains/atlas/ The Aquifer Formerly Known as Ogallala

28. Responsible Agency, 2004 & 2005

29. Measurement Procedures  Well locations verified with GPS  Depths measured with chalked steel tape  Measurements, info entered on-site using WaterWitch/WaterBug software  Repeat measurements for quality control  Efficient routing of teams for rapid completion (Jan. 8-13, 2005 for KGS)