1. Repairing the long-term salinity projection model for the Colorado River basin April 25-27, 2005 International Salinity Forum Riverside, California

2. Agenda Issues Addressed Our Solutions –Natural Flow Component –Natural Salt Component Additional Benefits Publications Concluding Remarks

3. Issues Addressed The model could not accurately simulate the historical period 1971-1990 Problems Identified: –Input data inconsistent –A changing natural flow and salt mass relationship –Limited and out-of-date documentation

4. Our Solutions Re-compute natural flow 1971-2000 –Addressing Data Inconsistencies Recomputing natural flow from 1971-95 Natural Flow = Historic Flow + Consumptive Uses and Losses +/- Reservoir Regulation –Addressing Methodological Inconsistencies RiverWare model computes natural flow –Ensures consistency

6. Our Solutions Develop a new natural salt model –Nonparametric local linear regression –K-nearest neighbor resampling Capture the changing relationship –Based on data from 1971-1995

9. Additional Benefits Better direct new research – understand salt loading resulting from irrigating agriculture –Changing land use from agriculture to M&I Completed peer reviews with journal articles and supporting documentation Begun process to move model input data to a secure database Involve Basin States during entire process

10. Publications Prairie, J., Rajagopalan, B., Fulp, T., and Zagona, E. (2005). "Statistical Nonparametric Model for Natural Salt Estimation." Journal of Environmental Engineering, 131(1), 130-138. Reclamation (1995). “Draft Upper Basin Consumptive Uses and Losses Report as Revised After Peer Review 1971-1995.” Clayton, R. (2004). “Upper Colorado River Consumptive Use Determination at CRSS Natural Flow Node Locations CY 1971-1995.” Bureau of Reclamation Prairie, J. and Callejo, R. (2005) “Natural Flow And Salt Computation Methods 1971-1995” Bureau of Reclamation

11. Concluding Remarks Reclamation has a working model that we have confidence in and can support New salt model can easily be updated New methods and data in CRSS Salinity Projection Model fully supported with documentation CRSS Salinity Projection Model implemented for 2005 Triennial Review Future research targeted to address upcoming issues

12. Repairing the long-term salinity projection model for the Colorado River basin For further information: http://cadswes.colorado.edu/~prairie