David Woodson

University of Colorado at Boulder

Subject Areas: Hydrology, machine learning, modeling, GIS, climate change, forecasting, Colorado River

 Recent Activity

ABSTRACT:

Code and data for streamflow forecasts of Upper Colorado River Basin spring flows, with lead times spanning 0- to 18-months.

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ABSTRACT:

Decadal (~10-years) scale flow projections in the Colorado River Basin (CRB) are increasingly important for water resources management and planning of its reservoir system. Physical models – Ensemble Streamflow Prediction (ESP) – do not have skill beyond interannual time scales. However, Global Climate Models have good skill in projecting decadal temperatures. This, combined with the sensitivity of CRB flows to temperature from recent studies, motivate the research question - can skill in decadal temperature projections be translated to operationally skillful flow projections and consequently, water resources management? To explore this, we used temperature projections from the Community Earth System Model – Decadal Prediction Large Ensemble (CESM-DPLE) along with past basin runoff efficiency as covariates in a Random Forest (RF) method to project ensembles of multi-year mean flow at the key aggregate gauge of Lees Ferry, Arizona. RF streamflow projections outperformed both ESP and climatology in a 1982-2017 hindcast, as measured by ranked probability skill score. The projections were disaggregated to monthly and sub-basin scales to drive the Colorado River Mid-term Modeling System to generate ensembles of water management variables. The projections of pool elevations in Lakes Powell and Mead – the two largest U.S. reservoirs that are critical for water resources management in the basin – were found to reduce the hindcast median root mean square error by up to -20 and -30% at lead times of 48- and 60-months, respectively, relative to projections generated from ESP. This suggests opportunities for enhancing water resources management in the CRB and potentially elsewhere.

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ABSTRACT:

Decadal (~10-years) scale flow projections in the Colorado River Basin (CRB) are increasingly important for water resources management and planning of its reservoir system. Physical models – Ensemble Streamflow Prediction (ESP) – do not have skill beyond interannual time scales. However, Global Climate Models have good skill in projecting decadal temperatures. This, combined with the sensitivity of CRB flows to temperature from recent studies, motivate the research question - can skill in decadal temperature projections be translated to operationally skillful flow projections and consequently, water resources management? To explore this, we used temperature projections from the Community Earth System Model – Decadal Prediction Large Ensemble (CESM-DPLE) along with past basin runoff efficiency as covariates in a Random Forest (RF) method to project ensembles of multi-year mean flow at the key aggregate gauge of Lees Ferry, Arizona. RF streamflow projections outperformed both ESP and climatology in a 1982-2017 hindcast, as measured by ranked probability skill score. The projections were disaggregated to monthly and sub-basin scales to drive the Colorado River Mid-term Modeling System to generate ensembles of water management variables. The projections of pool elevations in Lakes Powell and Mead – the two largest U.S. reservoirs that are critical for water resources management in the basin – were found to reduce the hindcast median root mean square error by up to -20 and -30% at lead times of 48- and 60-months, respectively, relative to projections generated from ESP. This suggests opportunities for enhancing water resources management in the CRB and potentially elsewhere.

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Stochastic Decadal Projections of Colorado River Streamflow and Reservoir Pool Elevations Conditioned on Temperature Projections
Created: Nov. 18, 2021, 10:13 p.m.
Authors: Woodson, David · Balaji Rajagopalan · Sarah Baker · Rebecca Smith · James Prairie · Erin Towler · Ming Ge · Edith Zagona

ABSTRACT:

Decadal (~10-years) scale flow projections in the Colorado River Basin (CRB) are increasingly important for water resources management and planning of its reservoir system. Physical models – Ensemble Streamflow Prediction (ESP) – do not have skill beyond interannual time scales. However, Global Climate Models have good skill in projecting decadal temperatures. This, combined with the sensitivity of CRB flows to temperature from recent studies, motivate the research question - can skill in decadal temperature projections be translated to operationally skillful flow projections and consequently, water resources management? To explore this, we used temperature projections from the Community Earth System Model – Decadal Prediction Large Ensemble (CESM-DPLE) along with past basin runoff efficiency as covariates in a Random Forest (RF) method to project ensembles of multi-year mean flow at the key aggregate gauge of Lees Ferry, Arizona. RF streamflow projections outperformed both ESP and climatology in a 1982-2017 hindcast, as measured by ranked probability skill score. The projections were disaggregated to monthly and sub-basin scales to drive the Colorado River Mid-term Modeling System to generate ensembles of water management variables. The projections of pool elevations in Lakes Powell and Mead – the two largest U.S. reservoirs that are critical for water resources management in the basin – were found to reduce the hindcast median root mean square error by up to -20 and -30% at lead times of 48- and 60-months, respectively, relative to projections generated from ESP. This suggests opportunities for enhancing water resources management in the CRB and potentially elsewhere.

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Resource Resource
Stochastic Decadal Projections of Colorado River Streamflow and Reservoir Pool Elevations Conditioned on Temperature Projections
Created: Nov. 19, 2021, 10:24 a.m.
Authors: Woodson, David · Balaji Rajagopalan · Sarah Baker · Rebecca Smith · James Prairie · Erin Towler · Ming Ge · Edith Zagona

ABSTRACT:

Decadal (~10-years) scale flow projections in the Colorado River Basin (CRB) are increasingly important for water resources management and planning of its reservoir system. Physical models – Ensemble Streamflow Prediction (ESP) – do not have skill beyond interannual time scales. However, Global Climate Models have good skill in projecting decadal temperatures. This, combined with the sensitivity of CRB flows to temperature from recent studies, motivate the research question - can skill in decadal temperature projections be translated to operationally skillful flow projections and consequently, water resources management? To explore this, we used temperature projections from the Community Earth System Model – Decadal Prediction Large Ensemble (CESM-DPLE) along with past basin runoff efficiency as covariates in a Random Forest (RF) method to project ensembles of multi-year mean flow at the key aggregate gauge of Lees Ferry, Arizona. RF streamflow projections outperformed both ESP and climatology in a 1982-2017 hindcast, as measured by ranked probability skill score. The projections were disaggregated to monthly and sub-basin scales to drive the Colorado River Mid-term Modeling System to generate ensembles of water management variables. The projections of pool elevations in Lakes Powell and Mead – the two largest U.S. reservoirs that are critical for water resources management in the basin – were found to reduce the hindcast median root mean square error by up to -20 and -30% at lead times of 48- and 60-months, respectively, relative to projections generated from ESP. This suggests opportunities for enhancing water resources management in the CRB and potentially elsewhere.

Show More
Resource Resource
Year-2 forecasts
Created: Sept. 21, 2022, 9:45 p.m.
Authors: Woodson, David · Balaji Rajagopalan · Edith Zagona

ABSTRACT:

Code and data for streamflow forecasts of Upper Colorado River Basin spring flows, with lead times spanning 0- to 18-months.

Show More