1. Overview and Issues of the High Plains Aquifer, Oklahoma, 2010 Mark F. Becker U.S. Geological Survey Oklahoma City, Oklahoma

2. Outline of Presentation Issues (addressed throughout presentation) Location and Setting Oklahoma Water Law Hydrology and Water-Quality Water-Uses and Effects of Withdrawal Future of Irrigated Agriculture Conclusions

3. Issues 1. Long way from State Capitol 2. Sparsely Populated (Small Legislative Representation) 3. Oklahoma Water Law 4. Groundwater Level Declines 5. Future for Irrigation

4. Issue #1: The Central High Plains and Oklahoma

5. Kansas Oklahoma Texas New Mexico Colorado Issue # 2: Sparse Population Estimated Population of Panhandle in 2009 was 30,035

6. Setting Overlies approximately 7,100 mi 2 in Oklahoma Texas County is Largest Ag Producer in OK Mean annual precipitation around 19-in/yr Temperature range: -25 o F to +110 o F Average lake evaporation = 62-in/year Average runoff (pre-1970) = 0.2-in/year

7. Land Use (Oklahoma Portion) 56% rangeland 40% dry cropland 4% irrigated cropland

9. Harvested Acres (Oklahoma Portion) Wheat2,600,000 acres Corn 800,000 Sorghum 700,000 Hay 300,000 Other 65,000

10. Livestock (Oklahoma High Plains) 620,000 cattle in 1992 750,000 cattle in 1997 20,000 swine in 1992 > 2,700,000 in 1999

11. Issue #3: Oklahoma Water Law Oklahoma has a “mining” based regulatory approach to groundwater Property Right Allows for depletion over time Allocations are for high capacity wells and until determined set at 2 acre-ft/ac/yr for land owned Does not recognize hydraulic connection to surface water No effective monitoring Kansas has highly regulated sustainable based law Texas has essentially no jurisdiction over groundwater

12. Hydrogeology Series of coalescing alluvial fans consisting of sand, clay, and gravel that can exceed 500’ in thickness Well yields can exceed 2,000 GPM Direction of groundwater flow is from west to east Recharge is distributed Recharge is relatively rapid Water-level declines from irrigation withdrawals

13. Center-pivot Irrigation began in the early 1960’s in Oklahoma

14. Center Pivot Technology Changed Irrigation Practices Land with rolling topography could be irrigated Circles are 0.5 mile in diameter Each well pumps about 1,500 gpm

15. Percent Ground-Water Use in the Central High Plains in 1992 Percent Water Use

16. Water Use in 2005 252Mgal/d

17. Groundwater Flow

18. Saturated Thickness (1998) >300 100-300 <50 50-100

19. Issue #4: Water-Level Declines Long-term effects on streamflow Ecosystems Treated municipal wastewater Increased pumping costs Potentially reduces irrigated agricultural opportunities Creates acrimony (whiskey’s for drinking, water’s for fighting)

20. Water-Level Changes to 1980 Declines more than 100 feet in Kansas, Oklahoma, and Texas Declines of 10-50 feet widespread Rises more than 25 feet in Nebraska Large areas of little on no change

21. Water-Level Changes to 1997 Areas of declines have expanded Areas of rises have expanded, especially in Texas and Oklahoma Large rises in Nebraska continue

22. Water-Level Change from Predevelopment to 1998 10-25 ± 10 Rise >50 25-50

23. Near Guymon 07232500 Stream Gaging Station Ground Water Well Optima Lake Canton Lake At Beaver 07234000 At Woodward 07237500 Near Seiling 07238000 Well A Lesson in Planning: The Beaver/North Canadian River Basin

24. Upstream face of Optima Dam in 1990 Aerial Photo by Dale Boyle, U.S. Geological Survey

25. Increases in Numbers of Large-Capacity Irrigation Wells in the Oklahoma Panhandle

26. Depth to Water in a key Oklahoma Well in the High Plains Aquifer

27. Percentage of no-flow days for the Beaver River near Guymon, Okla.

28. Annual Precipitation (bars) and 10-year moving average (line) for western Oklahoma

29. Annual flow volume (bars) and 10-year moving average (line) near Guymon (07232500)

30. Annual Peak Discharge (bars) and 10-year moving average (line) near Guymon, OK (07232500)

31. Recharge Myth #1: Recharge comes from snowmelt in the Rockies Myth#2: Aquifer receives little or no recharge Reality: Distributed recharge from precipitation

32. Estimated Depth to Water in Feet Tritium Units

33.  18 O/ 16 O VSMOW ‰ Deuterium VSMOW ‰

34. Predevelopment Recharge 4.0% of precipitation in sand-dune areas. Averaged 0.69 inches per year. 139,000 acre-feet per year. 14% of model area. 0.37% of precipitation in other areas. Averaged 0.07 inches per year. 85,000 acre-feet per year. 86% of model area.

35. Cultivated Dryland Recharge Extra recharge due to dryland cultivation 3.9% of precipitation over area in dryland; about 0.65 inches per year 345,000 acre-feet per year

36. Dryland Recharge 30 40 50 19401990 Depth to Water

37. Summary Statistics for Common Ions and Field Parameters

38. Issue # 5: Future of Irrigation Tied to prices of fuel and crops New technologies allow exploitation of lower well yields Genetically modified crops Low/No Till methods Economy of scale; larger farms, less farmers

39. Conclusion Politically, not well represented but recognized by the economic value. Contrasting water management strategies on borders Declines in water levels Increased costs Loss of surface water Potential for technological advances to keep irrigated agriculture a component

40. The End

41. OWRB Sites

42. Conclusions NO 3 is elevated in most wells NO 3 is found at all well depths 15 N indicates the presence of animal wastes Changes ahead as more data is evaluated

43. NO 2 + NO 3 mg/L as N Estimated Depth to Water in Feet OWRB Data

45.  15 N Air ‰ NO 2 + NO 3 mg/L as N Fertilizer Mixed Animal, Fertilizer, or Soil Animal

46. Types of Water-Quality Data (OWRB) Field measurements (temperature, pH, alkalinity, O 2, specific conductance) Chemical analyses (common ions, metals, nutrients, 15 N, 18 O, and deuterium) Age dating (tritium, tritium/helium, and 14 C)

47. Location of Central High Plains NAWQA Study Area New Mexico Colorado Kansas Oklahoma Texas Sub Unit Survey Reconnaissance Public Supply

48. NO 2 + NO 3 mg/L as N Tritium

49. Water-quality Data Collected in 1999 Oklahoma water resources board (OWRB)- 12 Wells NAWQA Sub Unit Surveys- 94 wells NAWQA Regional Transect - 5 well clusters (15 Wells) NAWQA reconnaissance - 5 wells NAWQA Public Supply Survey- 15 wells

50. Outline of Presentation Describe Oklahoma setting and similarities to the entire Central High Plains Describe Oklahoma High Plains study and High Plains NAWQA Water-quality in Oklahoma High Plains Conclusions

51.  15 N Air ‰ Estimated Depth to Water in Feet Fertilizer Mixed Animal, Fertilizer, or Soil Animal