1. January 25, 2008 Department of Chemistry, CSU Controls of Dryland Hydrology: Insights from Major Element and Stable Isotope Geochemistry of the Rio Grande and Pecos River Fasong Yuan, PhD Cleveland State University Dept. of Biological, Geological, and Environmental Sciences

2. January 25, 2008 Department of Chemistry, CSU OUTLINE Introduction Long-term Changes in Stream Chemistry Upper/middle Rio Grande Lower Rio Grande Pecos River Spatial Variations in TDS Oxygen-18 and Deuterium

3. January 25, 2008 Department of Chemistry, CSU Introduction Atmospheric Circulations El Niño Southern Oscillation (ENSO) Pacific Decadal Oscillation (PDO) The Rio Grande Basin Geomorphic Settings Land Use Land Cover Water Diversions and Water Quality Problem Statements

4. January 25, 2008 Department of Chemistry, CSU Atmospheric Circulations Normal Conditions El Niño Conditions [source: noaa.gov] El Niño Southern Oscillation (ENSO)

5. January 25, 2008 Department of Chemistry, CSU Atmospheric Circulations Pacific Decadal Oscillation (PDO) warm phasecool phase [Mantua et al., 1997]

6. January 25, 2008 Department of Chemistry, CSU ArizonaNew Mexico Texas Mexico Colorado Oklahoma PECOS RIVER RIO GRANDE Rio Grande Basin

7. January 25, 2008 Department of Chemistry, CSU Land Use Land Cover [Source: rivers.txstate.edu]

8. January 25, 2008 Department of Chemistry, CSU Dams Elephant B., 1916 Amistad, 1968 Falcon, 1953 Red Bluff, 1936

9. January 25, 2008 Department of Chemistry, CSU Downstream Changes in Flow and TDS of the Rio Grande

10. January 25, 2008 Department of Chemistry, CSU Flood in 1942 [source: US Forest Service]

11. January 25, 2008 Department of Chemistry, CSU Drought in 2004

12. January 25, 2008 Department of Chemistry, CSU Salt Crust near El Paso

13. January 25, 2008 Department of Chemistry, CSU Salt Cedar

14. January 25, 2008 Department of Chemistry, CSU Salt Crystals near Girvin

15. January 25, 2008 Department of Chemistry, CSU Pecos River near Girvin in 2005

16. January 25, 2008 Department of Chemistry, CSU (1) Approach One Long-term changes in stream chemistry Data Used: International Boundary and Water Commission (IBWC), United States and Mexico United States Bureau of Reclamation (USBR) United States Geological Survey (USGS)

17. January 25, 2008 Department of Chemistry, CSU Upper Rio Grande El Paso

18. January 25, 2008 Department of Chemistry, CSU Lower Rio Grande near Amistad Amistad

19. January 25, 2008 Department of Chemistry, CSU Lower Pecos River near Langtry, TX Langtry

20. January 25, 2008 Department of Chemistry, CSU Upper Pecos River near Pecos, NM Pecos, NM

21. January 25, 2008 Department of Chemistry, CSU Seasonal Change Pecos, NM Langtry

22. January 25, 2008 Department of Chemistry, CSU Log-linear Relationship Girvin Langtry

23. January 25, 2008 Department of Chemistry, CSU Summary Long-term stream hydrology and chemistry are largely determined by large scale atmospheric circulations (such as PDO). The mixed features identified in the lower valley are ascribed to contrasting climatic settings poor hydrologic connectivity lithologic heterogeneity

24. January 25, 2008 Department of Chemistry, CSU (2) Approach Two Downstream changes in stream flow and TDS of the Pecos River Data Used: United States Geological Survey (USGS) International Boundary and Water Commission (IBWC), United States and Mexico

25. January 25, 2008 Department of Chemistry, CSU Changes in Discharge and TDS Pecos River

26. January 25, 2008 Department of Chemistry, CSU Gibbs Model [Gibbs, 1970]

27. January 25, 2008 Department of Chemistry, CSU Model Development [Yuan and Miyamoto, 2005]

28. January 25, 2008 Department of Chemistry, CSU YM Model [Yuan and Miyamoto, 2005]

29. January 25, 2008 Department of Chemistry, CSU Conversion Formula

30. January 25, 2008 Department of Chemistry, CSU [Yuan and Miyamoto, 2005] YM Model Application

31. January 25, 2008 Department of Chemistry, CSU Cation Changes

32. January 25, 2008 Department of Chemistry, CSU Summary YM model is capable of identifying mechanisms that control stream TDS. The Pecos River receives most of the dissolved solids from the upper valley. Evaporation is an important process regulating water chemistry. Dilution dominates in the lower Pecos.

33. January 25, 2008 Department of Chemistry, CSU (3) Approach Three Characteristics of Oxygen-18 and Deuterium in the Pecos River Data Collection Stream Water- This Study and USGS Precipitation- Global Network of Isotopes in Precipitation (GNIP) Groundwater- Published Literatures

34. January 25, 2008 Department of Chemistry, CSU  -Notation (‰)

35. January 25, 2008 Department of Chemistry, CSU Pecos River : May 6-7, 2005 : March 7-8, 2005 : July 12, 2005

36. January 25, 2008 Department of Chemistry, CSU Precipitation Flagstaff, AZ Waco, TX Chihuahua, MX [original data from GNIP]

37. January 25, 2008 Department of Chemistry, CSU Global Meteoric Water Line (GMWL) Waco Chihuahua Flagstaff GW  D = 8  18 O + 10 d =  D - 8  18 O

38. January 25, 2008 Department of Chemistry, CSU  18 O and d-excess [original data from USGS] Santa Rosa Langtry Red Bluff

39. January 25, 2008 Department of Chemistry, CSU d-excess

40. January 25, 2008 Department of Chemistry, CSU Summary The Pecos River contains a range of variations in  18 O and  D Although relatively large variations, the averaged values of  18 O and  D of meteoric waters from the Gulf are relatively high. d-excess (d=  D-8  18 O) appears to be a better index capable of differentiating stream waters affected by evaporative enrichments.

41. January 25, 2008 Department of Chemistry, CSU Future Research Speciation analysis (e.g., sulfur) Stable isotope studies on sulfate (  34 S and  18 O) Microbial analysis

42. January 25, 2008 Department of Chemistry, CSU Acknowledgement Martinez Ignacio and Seiichi Miyamoto of Texas A&M Research Center at El Paso Anaya Gilbert of International Boundary and Water Commission, USA and Mexico Alyson McDonald of Texas Cooperative Extension at Fort Stockton