Soil-Water-Balance Recharge Estimates for the Upper Colorado River Basin under Climate Change

Project ID: 2005
Principal Investigator: Subhrendu Gangopadhyay
Research Topic: Water Supply Forecasting
Priority Area Assignments: 2015 (Climate Change and Variability Research), 2016 (Climate Change and Variability Research)
Funded Fiscal Years: 2015 and 2016
Keywords: groundwater, recharge, climate change, cmip-5

Research Question

Hypothesis

Groundwater supplies baseflow to streams and rivers in the Upper Colorado River Basin (UCRB), maintaining flow during time periods after snowmelt and peak runoff have been routed through the system. Reductions in groundwater recharge will result in reduced flow in the River and tributaries during baseflow-dominant times of the year and could negatively affect riparian vegetation and associated ecosystems and result in reduced water availability to meet agricultural, municipal and industrial water demands.

Research Questions

(1) How will projected climate conditions represented in the CMIP-5 archive affect groundwater recharge in the UCRB?

(2) Will changes in UCRB groundwater recharge from future climate conditions be driven mainly by changes in evapotranspiration or changes in precipitation?

Need and Benefit

As identified in the Long-Term User Needs document, Reclamation would like to address the information gap on climate change effects on groundwater and the resultant impacts to surface-water supply over the next several decades. At the same time, Reclamation would like to develop a methodology that could be applied drainage-basin by drainage-basin across the western US. The ideal assessment method should consistently provide information about the relative importance of groundwater in support of basin-specific surface-water flow and illustrate how changing climate conditions (i.e. changes in groundwater recharge) might impact future stream-flow volumes in these drainage basins.

This research will provide insights into changes in groundwater recharge from a changing climate in the UCRB, and impacts on streamflow for the basins.

Contributing Partners

Contact the Principal Investigator for information about partners.

Research Products

Bureau of Reclamation Review

The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.

Soil-Water-Balance Recharge Estimates for the Upper Colorado River Basin under Climate Change (final, PDF, 1.9MB)
By Subhrendu Gangopadhyay
Publication completed on September 30, 2016

Groundwater recharge in the Upper Colorado River Basin was simulated to better understand potential changes in thegroundwater system in response to projected climate change. Groundwater recharge is expected to be somewhat greater thanin the recent past, as a result of projected increases in precipitation.

Changes in groundwater recharge under projected climate in the Upper Colorado River Basin (final, PDF, 9.8MB)
By Fred Tillman, Subhrendu Gangopadhyay, Tom Pruitt
Publication completed on September 30, 2016

This research product summarizes the research results and potential application to Reclamation's mission.

Understanding the past to interpret the future: comparison of simulated groundwater recharge in the upper Colorado River basin using observed and GCM historical climate data (final, PDF, 2.4MB)
By Fred Tillman, Subhrendu Gangopadhyay, Tom Pruitt
Publication completed on September 30, 2016

This research product summarizes the research results and potential application to Reclamation's mission.

Changes in Projected Spatial and Seasonal Groundwater Recharge in the Upper Colorado River Basin (final, PDF, 1.1MB)
By Subhrendu Gangopadhyay, Tom Pruitt
Publication completed on January 24, 2017

This study quantifies projected spatial and seasonal changes in groundwater recharge within the UCRB from recent historical (1950-2015) through future (2016-2099) time periods, using a distributed-parameter groundwater recharge model with downscaled climate data from 97 Coupled Model Intercomparison Project Phase 5 (CMIP5) climate projections. Simulation results indicate that projected increases in basin-wide recharge of up to 15% are not distributed uniformly within the basin or throughout the year. Northernmost subregions within the UCRB are projected an increase in groundwater recharge, while recharge in other mainly southern subregions will decline. Seasonal changes in recharge also are projected within the UCRB, with decreases of 50% or more in summer months and increases of 50% or more in winter months for all subregions, and increases of 10% or more in spring months for many subregions.

Quantifying Projected Changes in Groundwater Recharge in the Upper Colorado River Basin (final, PDF, 729KB)
By Fred Tillman
Publication completed on March 01, 2017

This bulletin summarizes the research results and potential application to Reclamation's mission.

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Last Updated: 6/22/20