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Open-File Report 2009-1126

Prepared in cooperation with the National Park Service

Decision Support System for Evaluation of Gunnison River Flow Regimes With Respect To Resources of the Black Canyon of the Gunnison National Park

By Gregor T. Auble, Mark Wondzell, and Colin Talbert

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This report describes and documents a decision support system for the Gunnison River in Black Canyon of the Gunnison National Park. It is a macro-embedded EXCEL program that calculates and displays indicators representing valued characteristics or processes in the Black Canyon based on daily flows of the Gunnison River. The program is designed to easily accept input from downloaded stream gage records or output from the RIVERWARE reservoir operations model being used for the upstream Aspinall Unit.

The decision support system is structured to compare as many as eight alternative flow regimes, where each alternative is represented by a daily sequence of at least 20 calendar years of streamflow. Indicators include selected flow statistics, riparian plant community distribution, clearing of box elder by inundation and scour, several measures of sediment mobilization, trout fry habitat, and federal reserved water rights. Calculation of variables representing National Park Service federal reserved water rights requires additional secondary input files pertaining to forecast and actual basin inflows and storage levels in Blue Mesa reservoir. Example input files representing a range of situations including historical, reconstructed natural, and simulated alternative reservoir operations are provided with the software.

First posted July 13, 2009

For additional information contact:

Center Director, USGS Fort Collins Science Center
2150 Centre Ave., Bldg. C
Fort Collins, CO 80526-8118

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.

Suggested citation:

Auble, G.T., Wondzell, M., and Talbert, C., 2009, Decision support system for evaluation of Gunnison River flow regimes with respect to resources of the Black Canyon of the Gunnison National Park: U.S. Geological Survey Open-File Report 2009–1126, 24 p.




Study Area

Structure of Decision Support System

Basic Use


Daily Hydrologic Input

Secondary Input

Execution and Output

Indicator Variables

Box Elder Clearing

Plant Communities

Trout Fry Habitat

Sediment Mobilization

National Park Service Water Right


Minimum Flow

May–June Peak Flow

Shoulder Flow

Hydrologic Indicators

Annual Minimum Daily Discharge

Annual Mean Daily Discharge

Annual Maximum Daily Discharge

Annual 14-Day Maximum Daily Discharge

Ramp Rate

Flow Constancy

Coefficient of Variation of Monthly Discharge within Years

References Cited

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