1. Reclamation Climate Variabilaity Activities March 28, 2014 Tucson, AZ

2. Study Objective –Assess future water supply and demand imbalances over next 50 years –Develop and evaluate opportunities for resolving imbalances Study conducted by Reclamation and the Basin States in collaboration with stakeholders throughout the Basin A 3 year study that began in January 2010 and completed December 2012 A planning study – did not result in any decisions, but provides the technical foundation for future activities Colorado River Basin Water Supply and Demand Study

3. Water Supply Assessment Observed Resampled * Multiple realizations for each scenario Paleo Conditioned Paleo Resampled Downscaled GCM Projected Scenarios *:

4. Quantification of Water Supply Scenarios Projections of 2011-2060 Average Natural Flow at Lees Ferry Box represents 25 th – 75 th percentile, whiskers represent min and max, and triangle represents mean of all traces 1991 – 2010 average = 13.7 MAF

5. Moving Forward Next Steps after the Study

6. Basin Study Next Steps Workgroups

7. Next Steps Workgroups “…all that rely on the Colorado are taking initial steps — working together — to identify positive solutions that can be implemented to meet the challenges ahead.” Brings wider stakeholder group with expertise to address topics identified in the Basin Study More detailed analysis and discussion than was considered in the Basin Study

8. Data and Tool Development

9. RiverWare TM RiverSMART Manage input and output for many scenarios Automate simulation process

10. Climate Science Research

11. WaterSMART West Wide Climate Risk Assessments (WWCRA) –Reconnaissance level baseline risk and impact assessments related to supply and demand Basin Studies –Study of basins where imbalances in water supply and demand exist or are projected, including options to mitigate associated risks Landscape Conservation Cooperatives –Bring together science and resource management to inform climate adaptation strategies to address climate change Climate Science Centers –Provide natural and cultural resource managers with the tools and information they need to address the impacts of climate change

12. Reclamation Climate Change and Variability Research Climate Change and Water Working Group –Federal collaborators: Army Corps of Engineers, NOAA, USGS, EPA, NASA, and FEMA Downscaled CMIP3 and CMIP5 Climate and Hydrology Projections –Recent studies have relied on CMIP3 base hydrologies –Had only applied the BCSD and BCCA downscaling techniques Other research collaborators –NCAR, RISAs, Universities

13. Long-term and Short-term needs 13 Addressing Climate Change in Long-Term Water Resources Planning and Management: User Needs for Improving Tools and Information Short-Term Water Management Decisions: User Needs for Improved Climate, Weather, and Hydrologic Information

14. Recently release CMIP5 data

15. Improved techniques for climate projection downscaling and hydrologic impacts assessment Gap(s) Addressed Research Question(s)Collaborators/Schedule/Source of Support 2.03Information on the strengths and weaknesses of downscaled data… 3.03 Basis for culling or weighting climate projections … 4.01 Guidance on strengths and weaknesses of watershed hydrologic models/methods … 4.02Understanding how climate change should impact potential evapotranspiration and how it is represented in watershed hydrologic models. 7.02 Uncertainty information on regional climate projections … 7.04 …uncertainty information on system science and associated ways of portraying this science in a system model and the observations used to customize a model for a specific system. 1.How can we make greater use of projected changes in climate dynamics to downscale output from multiple GCMs? 2.How can we improve continental-scale hydrology simulations and better characterize hydrologic model uncertainty? 3.What is the relative importance of different sources of uncertainty in the portrayal of climate change impacts on hydrology Reclamation, US Army Corps of Engineers Schedule:  Fall 2013 – Baseline simulations and development of modeling infrastructure  Summer 2014 – Prototypes for intermediate-complexity downscaling and multi-model hydrology simulations  Summer 2015 – Information for the SECURE report Funding: Reclamation, US Army Corps of Engineers; complemented by NSF Graphic Precipitation from WRF & Simple Weather Model (SWM)

16. Colorado River Headwaters Project NCAR/MMM, University of Vienna, George Mason University, and the University of Texas A team of scientist from a variety of disciplines such as atmospheric science, hydrometeorology, climate and regional modeling, land–surface modeling, and social science will collaborate to investigate following questions: How high should model resolution be for the regional climate model to accurately simulate seasonal snowfall and snowpack in the Colorado Headwaters regions? Will the predicted increase in snowfall (caused by a warmer, moister climate) be enough to offset the accelerated melting and sublimation due to warmer temperatures? If so, will the increase in snowfall be sufficient to maintain river flow at current levels?

17. Colorado River Hydrology Workgroup Brings together Reclamation and Reclamation funded Colorado River Basin researchers University of Arizona, University of Colorado, and UNLV Topics being studied –Climate Teleconnections –Inter-Decadal Streamflow Projections –Hydroclimate analysis –Economic Analysis –Knowledge Exchange –Dynamical downscaling

18. Summary Reclamation has been and continues to be committed to a variety of ongoing efforts that address long-term risks and drought Basin Study Next Steps workgroups aim to further explore areas identified in the Study to identify positive solutions to challenges ahead There is a strong emphasis on collaboration with stakeholders, other departments or agencies, as well as the research community

19. Questions?