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Model analysis of integrated surface- and ground-water hydrologic response to climate change

Project ID: 2885
Principal Investigator: Jennifer Johnson
Research Topic: Water Operation Models and Decision Support Systems
Funded Fiscal Years: 2009
Keywords: None

Research Question

Reclamation's early investigations of the effects of climate change on basin hydrology have been limited to estimating changes to streamflows developed from surface water budgets. The proposed research will apply existing tools to develop an approach to simulate integrated surface- and ground-water response to climate change.

The research will answer:

* How can existing tools be applied to determine the anticipated changes in ground- and surface-water hydrologic systems under global climate change?

* Will the determination of changes in soil moisture, ground water levels, ground water discharge to streams, and total streamflow provide meaningful support to decision-makers?

* How will changes in temperature and timing, amount, and form of precipitation affect water availability for ecosystems?

* How will changes in temperature and timing, amount, and form of precipitation affect water availability for irrigation, municipal and industrial (M&I), Tribal water rights, and streamflows for habitat?

Need and Benefit

The development of successful resource management strategies is dependent on Reclamation's ability to anticipate hydrologic response to the range of probable future climate trends and associated uncertainties. Reclamation's preliminary investigations in climate change have applied probable temperature and precipitation changes to estimate anticipated changes in surface runoff. These investigations have demonstrated increased stress on Reclamation reservoirs, consequences to water rights and Reclamation contracts, and increased flood risk.

These early investigations have assumed negligible effects of climate change on ground-water hydrology. However, the changes in temperature and precipitation associated with climate change also produce changes in ground-water recharge which alter base flow and total river discharge. Base flow is a significant contributor to total river discharge in many Reclamation projects and can not be ignored in developing reservoir management and operations strategies.

The proposed project will explore an approach to identify the integrated response of the surface- and ground-water hydrologic systems to climate change. Particular attention will be focused on the feedback between soil-moisture-driven changes in vegetation and changes in evapo-transpiration in the overall hydrologic response of the surface- and ground-water systems. Simulated response, in the form of changes in ground-water recharge, base flow and total river discharge, can then be applied in subsequent studies to evaluate the reliability of water supply, potential flood risk, and the effects of climate change on ecosystems and protected and endangered species. A case study of the Upper Deschutes River Basin will be presented.

Contributing Partners

None

Research Products

Independent Peer Review

The following documents were reviewed by qualified Bureau of Reclamation employees. The findings were determined to be achieved using valid means.

Model Analysis of the Hydrologic Response to Climate Change in the Upper Deschutes (final, PDF, 7.5MB)
By Marshall Gannett
Report completed on March 25, 2013

A daily mass and energy balance model (Deep Percolation Model) developed for the Deschutes Basin along with 1/16th degree daily downscaled climate data (University of Washington Climate Impact Group) was used to evaluate changes in runoff timing and recharge in an effort to show potential impacts to the groundwater system due to climate change. The study showed that the sensitivity of the system to climate change depended on the spatial scale and geologic controls.
Keywords: deschutes, oregon, climate change, groundwater, deep percolation model

Document ID 688: this document contains protected information and it cannot be freely downloaded from USBR.gov. Contact the Principal Investigator to request a copy of this document.

This information was last updated on December 22, 2014
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