Repairing the long-term salinity projection model for the

Colorado River basin

April 25-27, 2005International Salinity Forum

Riverside, California

Agenda

• Issues Addressed

• Our Solutions– Natural Flow Component– Natural Salt Component

• Additional Benefits

• Publications

• Concluding Remarks

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relationship– Limited and out-of-date documentation

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

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

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

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

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

Repairing the long-term salinity projection model for the

Colorado River basin

For further information:http://cadswes.colorado.edu/~prairie