Assessment of Hydrologic Response to Climate Change in the Upper Deschutes Basin, Oregon

M. Scott WaibelMarshall W. Gannett

Heejun ChangChristina L. Hulbe

Purpose of Research

• There is broad interest on the part of resource managers and the general public regarding response of streams and groundwater to probable climate change.

• Most irrigation water in the upper Deschutes Basin comes from storage reservoirs that are supplied by streams flowing from the Cascade Range, many of which are groundwater fed.

• These interests are addressed here using coupled groundwater recharge and flow models driven by GCM output.

MODIS image, 25 November 2002, NASA Visible Earth archive Inset from Gannett et al. 2001

Upper Deschutes Basin, Central Oregon

Models and products used

• Global Climate Model (GCM) weather data downscaled to 1/16th degree using the Bias-Correction and Spatial Disaggregation method.

• The Deep Percolation Model (DPM) of Bauer and Vaccaro (1987) as applied in the upper Deschutes Basin by Boyd (1996).

• A MODFLOW regional groundwater model calibrated to the upper Deschutes Basin by Gannett and Lite (2004).

Methods

• 8 GCMs

2 IPCC emission scenarios

= 16 runs

• 2 ensembles: DPM hydrologic budget results from the eight runs are averaged for each emission scenario.

Downscaled GCMs used as ensembles for both emission scenarios

Model Name Institution CountryCCSM3 National Center for Atmospheric Research USA

CNRM-CM3 Centre National de Recherches Meteorologiques France

ECHAM5 / MPI-OM Max Planck Institute for Meteorology Germany

ECHO-G Meteorological Institute of the University of Bonn Institute of KMA Model and Data Group

Germany Korea

HadCM3 Hadley Centre for Climate Prediction and Research UK

IPSL-CM4 Institut Pierre Simon Laplace France

MIROC 3.2 Center for Climate System Research, University of Tokyo National Frontier Research Center for Global Change Institute for Environmental Studies

Japan

PCM National Center for Atmospheric Research USA

Ensemble means and medians generally outperform any single GCM model

-adapted from Gleckler et al., (2007)

Methods (Continued)

• In-place recharge and runoff

Examined using basin-wide averaged mean monthly hydrographs and seasonal spatial maps.

• DPM recharge and evapotranspiration output used for inputs to the regional groundwater flow model.

Methods (Continued)

• Changes in groundwater discharge to select stream reaches within the three main discharge areas of the basin were examined using mean monthly hydrographs.

• Statistical testing was employed to confirm

changes between four climate periods in the 21st century for basin-wide mean monthly and mean seasonal results.

DPM

• Essential Parameters– Elevation– Long term annual

precipitation– Soil Properties– Land Cover

Elevation

DPMLong term annual precipitation (inches)

DPM

Soils Land cover

Important parameters for partitioning water

DPM Forcings

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ccsm3 a1b cnrm a1b

echo g a1b echam5 a1b

hadcm3 a1b ipsl a1b

miroc a1b EMEAN a1b

pcm1 a1b

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miroc b1 EMEAN b1

pcm1 b1

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echo g b1 echam5 b1

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pcm1 b1

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miroc a1b EMEAN a1b

pcm1 a1b

Temperature and precipitation: downscaled GCM time series averaged basin-wide

A1B Temp B1 Temp

B1 PrecipA1B Precip

Basin-wide average response to climate change

2 emission scenario ensemble means

4 climate periods

DPM basin-wide mean monthly change Precipitation

DPM basin-wide mean monthly change Snowpack

DPM basin-wide average changes Recharge

Runoff

A1B

A1B

B1

B1

Spatial distribution of changes in recharge and runoff 2050s relative to 1980s

MODIS image, 25 November 2002, NASA Visible Earth archive

1980s simulated recharge

SRES A1B 2050s change in recharge

1980s simulated runoff

SRES A1B 2050s change in runoff

Changes in baseflow

Odell Creek A1B emission scenario

Inflow to Lower Deschutes River A1B Emission Scenario

A1B Mean annual changes in recharge

2020s 2050s 2080s

percentchange

absolutechange

Summary• The DPM predicts a shift in timing of runoff and

recharge for both emission scenarios with a shift toward earlier runoff and recharge.

• Shifts in the timing of recharge are observed primarily in the baseflow hydrographs of high elevation streams.

• Volumetric changes in groundwater discharge to streams likely result from spatial changes in recharge.

References

Bauer, H., and Vaccaro, J., 1987, Documentation of a deep percolation model for estimating ground-water recharge: US Geological Survey Open-File Report, p. 86-536.

 

Boyd, T., 1996, Groundwater recharge of the middle Deschutes Basin, Oregon: Portland, Oregon, Portland State University: MS thesis, 86 p.

 

Gannett, M. W., Lite, K. E., Jr., Morgan, D. S., and Collins, C. A., 2001, Ground-water hydrology of the upper Deschutes Basin, Oregon: United States Geological Survey, 77 p.

 

Gleckler, P., Taylor, K., and Doutriaux, C., 2008, Performance metrics for climate models: Journal of Geophysical Research, v. 113, no. D6, p. D06104.

Range of basin-wide average recharge and runoff anomalies

winter2020s 2050s 2080s -0.1 0.7 1.01.4 2.0 2.6

spring2020s 2050s 2080s

0.0 -0.5 -0.9-1.3 -1.7 -2.2

winter2020s 2050s 2080s -0.1 0.1 0.30.6 0.9 1.1

spring2020s 2050s 2080s

0.0 -0.2 -0.4-0.6 -0.8 -1.0

Winter Spring Winter Spring

—from Bauer and Vaccaro (1987)

conceptual model of the water budget used by the DPM

Deep Percolation Model basics

SRES A1B 1980s Evapotranspiration

SRES A1B 2050s Evapotranspiration

Acknowledgments

• Thesis Committee– Christina Hulbe, Department of Geology, PSU– Marshall Gannett, USGS Oregon Water Science

Center– Heejun Chang, Department of Geography, PSU– Ken Cruikshank, Department of Geology, PSU

• Lenny Orzol, USGS Oregon Water Science Center

• Leslie Stillwater, Bureau of Reclamation

This work was funded through a Bureau of Reclamation Science and Technology Grant.