1. Agenda Project overview (brief) Modeling update (preliminary results) Next steps… Integration pathways

2. Modeling status update: 11/13/2012 Land-cover, meteorology, and desert dust Explore hydrologic impacts and sensitivities www.nsf.org Snow Water Equivalent (SWE)Discharge (Q) magnitude and timing Domain: catchments with range of MPB and dust impacts; varying hydro-climatology, Distributed hydrology soil vegetation model (DHSVM) Q (m 3 /s) Month Boulder Cr. Fish Cr. Snake R. Uncompaghre R. Painter et al., 2010

3. Current modeling status Snake R. set-up complete – other (3) river basins nearly ready… Local precip./temperature still open issues; Spatial improvements in cold-season precip. from Molotch et al. (SWE recon.). **Preliminary** sensitivities complete Calibrations hinge upon resolving precip./temperature issues… (examining individual years)

4. Modeling system Relevant Details: Dust-on-snow: Observation-based dust loading/snow albedo scenarios MPB: Satellite derived LAI-change MPB: Vegetation classification 100 m spatial resolution -Courtesy Jeff Deems

5. Example: Snake R. Flows into Dillon Reservoir – Denver Water Changes in leaf-area index (LAI) used to characterize beetle kill Explore ‘end-points’, 2000 - 2011 Snake R. Max. LAI: 2003 Max. LAI: 2006 -Courtesy Jeff Deems -Courtesy Brian Buma 500m MODIS satellite imagery (2002-2011) MPB Scenario: Apply maximum MPB impact to Evergreen areas, reducing canopy LAI Dust scenarios: Alter modeled snow albedos based on observed dust impacts.

6. Preliminary results

7. Model Results: Snake R. SWE (m) PRISM SWE 1 Apr., 2005 Considerable increase in spatial detail when using Molotch et al. SWE reconstruction to distribute winter precip (versus PRISM). SWE (m) SWE 1 Apr., 2005 Molotch et al. SWE recon. Cold season precip distribution

8. Model Results: Snake R. SWE (m) CONTROL: Moderate dust, no beetle impact Avg. SWE 1 Apr. MPB leads to higher accumulation of Snow Water Equivalent (SWE) Considerable variation between wet and dry years (not shown) SWE change (m) Difference Map Less More SWE (m) Scenario: Maximum MPB impact Avg. SWE 1 Apr. Residual

9. Relative model sensitivities Low Moderate Extreme WY200 6 SWE (mm) None Full MPB Month Dust enhances snowmelt Opposing effect of MPB on SWE, non-uniform, asynchronous… Low & Full MPB Moderate Extreme & Full MPB Month Relative dust impacts Relative MPB impacts Combined MPB & Dust Photo: Chris Landry www.denverpost.org WY200 6

10. Preliminary Model Streamflow Results Averaged 2000-2011 water years Low Moderate Extreme Discharge @ Montezuma (m 3 /s) Relative dust impacts Relative MPB impacts None Full MPB Changes in melt rate control peak runoff timing and magnitude (dust) MPB impacts also affect warm-season flow (reduced evapotranspiration) Month Water Yield (ac-ft/year) Low & Full MPB Moderate Extreme & Full MPB Combined MPB & Dust Month Averaged 2000-2011 water years Water Yield (ac-ft/year) +1.8% +1.1% +9.1% +11.6% +9.9%

11. Preliminary Conclusions Dust-on-snow enhances snowmelt, causing earlier peak streamflow MPB leads to higher SWE accumulation Model sensitivities from Snake R. show reduction of canopy cover increases water yield on the order of 10% Work in progress – compare other 3 basin responses, incorporate satellite-based MPB propagation patterns, greater spatial extents Potential points of integration with CBRFC: – Adjust melt factors? – Adjust ET demand?