Collaborative Research on Upper Colorado River Basin Streamflow and Drought. Designing and Implementing User-driven Research

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1 Collaborative Research on Upper Colorado River Basin Streamflow and Drought Designing and Implementing User-driven Research Connie Woodhouse School of Geography and Development University of Arizona With Adam Csank, Steph McAfee (Univ. of Nevada, Reno), Greg Pederson (USGS-Bozeman), Greg McCabe (USGS-Denver), and Steve Gray (USGS-Anchorage)

2 ANNUAL FUNDING OPPORTUNITY FISCAL YEAR 2014 U.S. Department of the Interior Southwest DOI Climate Science Center Proposal Review Criteria Scientific merit and quality of the proposed research. Management Significance Coordination and Engagement with science beneficiaries Study Team qualifications Budget/work plan Prospective PIs are advised to seek out and establish working partnerships with local or regional stakeholders from relevant organizations concerned with management of natural resources. Proposals that demonstrate clear engagement with stakeholders from such organizations, showing clear benefits through a collaborative process, will be evaluated more favorably.

3 Water management partners Dave Kanzer, Eric Kuhn: Colorado River District (State of CO) Charlie Ester, Jon Skindlov: Salt River Project, Arizona Laurna Kaatz, Steve Schmitzer, Mark Waage: Denver Water, Colorado Jim Prairie, Carly Jerla: Bureau of Reclamation, Lower Colorado District Paul Miller, Michelle Stokes: NOAA Colorado Basin River Forecast Center Kevin Werner: NOAA Regional Climate Services Director, Western Region

4 Stakeholder-driven Research Questions: How have the contributions of antecedent soil moisture, spring temperatures, and total cool season precipitation varied during the major periods of low flow in the upper Colorado River basin (UCRB)? Using tree-ring reconstructions these variables, how have these contributions varied over past centuries? Differences in cooler and warmer periods? What is the sensitivity of UCRB low flows to different scenarios of changes in antecedent soil moisture, winter precipitation, and winter/spring temperatures projected by CMIP5 models? Project products: Research results and data Management-identified information and products Project web page, with access to data Semi-annual report to Advisory Board with solicitation of feedback Conference presentations, peer-reviewed publications Publication targeting stakeholders with results relevant to water management Workshop for water resource managers

5 Colorado River Basin: Water for ~ 40 million people (including outside the basin) 3 million acres (1.2 million ha) of irrigated agriculture Vital hydropower Storage: 60 million acre feet (maf), or four years of the 20 th century average annual flow in Lakes Mead and Powell

6 Current Management Challenges in the Colorado River basin Over-allocation Increasing demand Drought Climate change

7 How have the contributions of antecedent soil moisture, spring temperatures, and total cool season precipitation varied during the major periods of low flow in the upper Colorado River basin (UCRB)? Part 1. Examination of droughts Part 2. Identify and quantify contributions of temperatures and soil moisture on Colorado River flow

8 Data Gridded climate data from PRISM for total monthly precipitation, average monthly temperature (4 km resolution) Monthly soil moisture (storage or storage capacity) output from two hydrologic models McCabe and Wolack (2011) monthly water balance model Colorado Basin River Forecast model (base on Sac-SMA model) Annual* natural flow estimates for the Colorado River at Lees Ferry from US Bureau of Reclamation Analysis period: *annual here is the water year, October-September

9 Part 1 Colorado River at Lees Ferry, natural flows, Major Droughts

10 0.9 Major UCRB Droughts percentile WY flow O-A precip AprT MarMayT MarJulT OctSoil NovSoil 1930s 1950s 1960s 1970s 1980s90s 2000s Average values for each hydroclimatic variable across all years in a given drought period, color coded by drought 10

11 percentiles 1930s Individual years with in major droughts: percentile values of WY flow, and variables that influence flow 1950s percentile percentiles percentiles 2000s WY flow Oct-Apr precipitation April temperature October soil moisture

12 percentiles 1930s Individual years with in major droughts: percentile values of WY flow, and variables that influence flow percentile percentiles 1950s WY flow Oct-Apr precipitation April temperature October soil moisture 2000s percentiles

13 Part 2 Quantifying the contribution of temperature and antecedent soil moisture in annual flow Stepwise model with pool of 6 predictors (Oct-Apr precipitation; March, March-May, Mar-Jul temperature; Oct, Nov soil moisture), Step Multiple Multiple R-square F - to p-level Variables +in/-out R R-square change entr/rem included OctAprP MarJulT novsoil

14 Observed and estimated flow, precipitation-only model Observed and estimated flow, precipitation-only and precipitation + temperature models

15 Residuals (errors) for precipitation-only and precipitation + temperature models

16 Does the addition of temperature to the precipitation-only model improve the model fit during particular periods? Years of highest and lowest tercile Colorado River flows are plotted with periods when model with temperature improves or worsens model fit

17 Does the addition of temperature to the precipitation-only model improve the fit during periods of major drought? Years of highest and lowest tercile Colorado River flows are plotted with periods when model with temperature improves or worsens model fit. Shading indicates periods of major drought.

18 Does the addition of fall soil moisture to the precipitation + temperature model improve the fit during particular periods? Years of highest and lowest tercile Colorado River flows are plotted with periods when model with soil moisture improves or worsens model fit

19 Colorado river flow values (in percentile) for the 10 years with the most improved fit when temperature is added to the precipitation-only model Colorado river flow values for the 10 years with the most improved fit when soil moisture is added to the precipitation + temperature model

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21 Summary Spring/summer temperatures and antecedent fall soil moisture appear to influence Colorado flow in *some* years Temperatures may have more influence in dry years while soil moisture may influence flows in the wettest years There are a number of directions we could take this. Our next step is to report results to our water management partners to determine the usefulness and relevance, and to discuss how to proceed.