American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Steve Markstrom U.S. Geological Survey Lakewood, Colorado

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Climate Change Effects on Western Riparian Forests:  Flood Timing, Tree Seed Dispersal Timing,  and Seedling Establishment  Patrick Shafroth & Laura Perry (USGS-FORT)  Lauren Hay, Roland Viger, & Steve Markstrom (USGS- MoWS)  Glen Liston (CSU-CIRA)  David Blodgett & Nathaniel Booth (USGS-CIDA)

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Cottonwood and Willow Establishment Cottonwoods and willows have specific requirements for germination and establishment Small, short-lived, non-dormant seeds Must land on bare, moist surfaces to survive Only establish in occasional years with the right conditions

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Seedlings that germinate on moderately high surfaces desiccate as floodwaters recede Seedlings that germinate on low surfaces are scoured away by ice and floods Base flow Recruitment band Too high – drought stress Too low – ice and flood scour

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Research Question: Will warming associated with climate change decouple the timing of seed dispersal from spring floods?

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Precipitation-Runoff Modeling System (PRMS)

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Coarse Resolution PRMS model for South Platte River, Front Range in Colorado 25,000 km2 184 Stream Segments 368 HRUs

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Stream Gage Information and PRMS Parameter Regionalization

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 PRMS Stream Flow Calibration USGS CACHE LA POUDRE RIVER AT MOUTH OF CANYON, NEAR FORT COLLINS, CO

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 PRMS Stream Flow Calibration USGS ST. VRAIN CREEK AT LYONS, CO.

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 PRMS Stream Flow Calibration USGS SOUTH BOULDER CREEK NEAR ELDORADO SPRINGS, CO.

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 PRMS Stream Flow Calibration USGS CLEAR CREEK ABV WEST FORK CLEAR CREEK NR EMPIRE CO

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 PRMS Stream Flow Calibration USGS SOUTH PLATTE RIVER BELOW CHEESMAN LAKE, CO

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Seed dispersal phenology Weekly site visits, 2010 and trees per species per site

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 PRMS simulation showing timing of stream flow for 1995 snow melt season

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 PRMS coarse resolution stream segment nodes

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13, 2012 Evaluation of snow melt timing with PRMS model: Historical record Climate projections Land use changes Geography and topography

American Water Resources Association 2012 Annual Conference Jacksonville, Florida November 13,