Flint

1. Integrated watershed scale response to global change in selected basins across the United StatesSteven Markstrom U.S. Geological Survey, National Research Program, Modeling of Watershed Systems Denver, Colorado Yakima Flathead Starkweather Cathance Trout Lake Sprague Black Earth Spring Sagehen Yampa Clear Feather Pomperaug East Flint Watershed scale response to climate change across the United States • 14 basins from different hydroclimatic regions selected as study sites. • General Circulation Model (GCM) climate change scenarios used as drivers to evaluate hydrologic responses using a watershed model • Long term goal is to provide the foundation for hydrologically-based climate-change studies across the nation.

2. Vining Mastin Fulton Yakima Starkweather Spring Dudley Chase Trout lake Flathead Cathance Hunt, Westenbroek, Walker Bjerklie Risley Sprague Pomperaug Koczot Feather Blackearth Markstrom, Regan Sagehen Hay, Viger Yampa Hunt, Westenbroek, Walker Battaglin, Hay Flint East Christiansen Clear Methodology for Assessing Climate Change General Circulation Model GCM grid scale A watershed model (PRMS) exists for each of these basins. Need future estimates of daily precipitation and maximum and minimum temperature at the station locations used in each of these watershed models.

3. GCM Simulations • Scenarios in the IPCC Special Report on Emissions Scenarios • 20C3M -- represents the IPCC SRES climate of the 20th century • SRESA2: very heterogeneous world with high population growth, slow economic development and slow technological change. • SRESA1: assumes a world of very rapid economic growth, a global population that peaks in mid-century and rapid introduction of new and more efficient technologies. A1 is divided into 3 groups: • fossil intensive (A1FI), • non-fossil energy resources (A1T) • balance across all sources (SRESA1B). • SRESB1: a convergent world, with the same global population as A1, but with more rapid changes in economic structures toward a service and information economy.

4. GCM scale Basin scale Methodology for Assessing Climate Change Statistical Downscaling • Derived by calculating the change in climate from present to future conditions simulated by each GCM. • GCM current climatic conditions (1988-1999). • Climate change fields (% changes in precipitation and degree changes in temperature) computed for monthly 12-year moving periods using GCM current and future conditions. Climate Change Fields

5. Coarse GCM Yampa River Basin HRU Fine March -- Snow-covered Area Basin 100 80 60 40 20 GCM Scenario: SRESB1 SRESA1B SRESA2 Snow covered Area, % 100 80 60 40 20 2020 2040 2060 2080 HRU with Ski Area 2020 2040 2060 2080

6. +50% +50% +50% +50% -50% -50% -50% -50% Percent Change in Streamflow B1 A1B A2

7. Markstrom, S.L., Hay, L.E., Ward-Garrison, C., Risley, J.C., Battaglin, W.A., Bjerklie, D.M., Chase, K.J., Christiansen, D.E. Dudley, R.W., Hunt, R.J., Koczot, K.M., Mastin, M.C., Regan, R.S., Viger, R.J., Vining, K.C., and Walker, J.F., 2012, An integrated watershed scale response to climate change for selected basins across the United States: U.S. Geological Survey Scientific Investigations Report 2011-5077, 143 p. Battaglin, W., Hay, L. E., and Markstrom, S. L., 2011, Simulating the Potential Effects of Climate Change in Two Colorado Basins and at Two Colorado Ski Areas: Earth Interactions. Bjerklie, D. M., Trimbley, T. J., and Viger, R. J., 2011, Simulated watershed-scale snowfall and groundwater recharge trends from 1961- 2007 and projected to the end of this century based on selected climate-change scenarios for basins draining to Long Island Sound: Earth Interactions. Christiansen, D. E., Markstrom, S. L., and Hay, L. E., 2011, Impacts of Climate Change on Growing Season in the United States: Earth Interactions. Hay, L. E., Markstrom, S. L., and Ward-Garrison, C., 2011, Watershed-scale response to climate change through the 21st century for selected basins across the United States: Earth Interactions. Koczot, K. M., Markstrom, S. L., and Hay, L. E., 2011, Effects of baseline conditions on the hydrologic effects of climate change: Earth Interactions. Mastin, M. C., Chase, K. J., and Dudley, R. W., 2011, Changes in Spring Snowpack for Selected Basins in the United States for Different Climate-Change Scenarios: Earth Interactions. Milly, P. C. D., and Dunne, K. A., 2011, On the hydrologic adjustment of climate-model projections: the potential pitfall of potential evapotranspiration: Earth Interactions. Risley, J., Moradkhani, H., Hay, L. E., and Markstrom, S. L., 2011, Statistical Trends in Watershed Scale Response to Climate Change in Selected Basins across the United States: Earth Interactions. Viger, R. J., Hay, L. E., Markstrom, S. L., Jones, J. W. and Buell, G. R., 2011, Hydrologic Effects of Urbanization and Climate Change on the Flint River Basin, Georgia: Earth Interactions. Walker, J. F., Hay, L. E., Markstrom, S. L., and Dettinger, M. D., 2011, Characterizing climate-change impacts on the 1.5-year flood flow in selected basins across the United States: a probabilistic approach: Earth Interactions.