Below is the current on-going model development under the Colorado River Modeling Work Group (Modeling Work Group) in order to apply the research being pursued under the Colorado River Hydrology Work Group in operations and planning models.

 
1. Development of new “Probabilistic Mid-Term” model

• This model will have a simulation horizon of 2-10 years, take a range of inflows for input, and express results in probabilistic terms. It will be developed in parallel with the 24-Month Study.
  
  
• Timeline is to complete first version of model by December 2010.

 
2. Analyze hydrologic scenarios that include climate information in the Colorado River Simulation System (CRSS)

• This project will utilize climate projections from the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset. Projections from this dataset have been downscaled by Reclamation’s Research & Development Office in partnership with the Lawrence Livermore National Laboratory (LLNL) and Santa Clara University. The downscaled datasets are stored and served at the LLNL Green Data Oasis.
  
  
• Transient runoff will be generated for all 112 available downscaled WCRP CMIP3 climate projections, covering three future emission scenarios, using the Variable Infiltration Capacity (VIC) model. This will be done in collaboration with AMEC Earth & Environmental.
  
  
• Future runoff sequences will be developed by blending the runoff generated from VIC and the paleo record using the Nonparametric Paleo Conditioned technique described in Prairie et al. 2008.
  
  
• Effects on the Colorado River system will be analyzed by performing simulations in CRSS that incorporate future runoff sequences.
  
  
• Timeline is to complete analysis by May 2010.

More information, including status updates of development of these models, will be added to this site when it becomes available.

In addition to the above projects, the Modeling Work Group produces a set of “official” CRSS simulations twice a year, in January and August. Each set of simulations projects Colorado River system conditions from the current year through 2026 utilizing three different stochastic techniques to represent hydrologic uncertainty. The techniques re-sample the observed natural flow record (Direct Natural Flow), the paleo record reconstructed by Meko et al., 2007 (Direct Paleo) and blends both records (Nonparametric Paleo Conditioned). More information regarding these techniques can be found in Appendix N of the Final EIS on Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead .

For more information relating to this modeling work, please contact CRBclimateresearch@usbr.gov.