1. Unintended Consequences due to Salinity Management – Example from the Lower Colorado River Multi-State Salinity Coalition 2012 Annual Conference January 25, 2012 Chuck Cullom Colorado River Programs Manager

2. Colorado River Basin Study Structure and Schedule Summary of Key Activities Upcoming Meetings Further Discussion, Follow- up Complex River System 10 major reservoirs 14.7 maf Av. Supply 34 million people 4 million irrigated acres Salt load long-term concern to users

3. Distribution of Flow and Salt Load Salinity increases downstream Natural sources Springs Tributaries Evaporation Ag runoff M&I discharges

4. Lower Colorado River System

5. Lower Colorado River Key Facilities Study Structure and Schedule Summary of Key Activities Upcoming Meetings Further Discussion, Follow- up Imperial Dam Point of diversion for 5 maf/yr Morelos Dam Point of delivery for Mexico - 1.5 maf/af Yuma Desalting Plant Cienega de Santa Clara Significant wetland in Mexico relying on US drainage water

6. Salinity History in the Lower Colorado River

7. Lower Colorado River Salinity Requirements Study Structure and Schedule Summary of Key Activities Upcoming Meetings Further Discussion, Follow- up Numeric Criteria Hoover – 723 ppm Parker – 747 ppm Imperial – 879 ppm International Water Treaty Delivery point = Morelos Dam Salinity Differential Imperial Dam + 115 ppm +/- 30 ppm

8. Sources of Water for Delivery to Mexico Colorado River Water Natural drainage Ag drainage Pumped Drains MAXIMIZE Efficient Water Management + MEET Treaty Requirements

9. Yuma Area Return Flows ~80% CR Water ~20% Drainage Linkage between Surface flows Drainage Pumping

10. Yuma Area Salinity Management + Accounting

11. Alternatives

12. What do we already know? YDP operated at 30% capacity from May 3, 2010 to March 26, 2011 YDP operations diverted flow away from Bypass Drain/Ciénega YDP operations added brine to Bypass Drain 30,000 acre-feet of “arranged water” added to Bypass Drain/Ciénega in 18 month period from Oct 29, 2009 until April 28, 2011 Magnitude 7.0 earthquake, April 4, 2010 Extensive fire, March 23-25, 2011 There are no simple experiments in nature