Glen Canyon Dam Operations
Glen Canyon Dam is the principle water storage unit of the Colorado River Storage Project (CRSP). The CRSP was authorized on April 11, 1956 to regulate the flow of the Colorado River; provide for flood control; provide for storage and delivery of water for irrigation, municipal, industrial, and other beneficial purposes; and generate electrical power. The CRSP also provides for recreation and improves conditions for fish and wildlife. Construction of the CRSP water storage facilities, including Glen Canyon Dam, was critical to the development of the Upper Colorado River Basin’s water and power resources.
The initial operation of Glen Canyon Dam focused primarily on storing water, releasing water to the Lower Basin states pursuant to the Colorado River Compact and generating power. Water releases through the powerplant fluctuated as the powerplant responded to power system load changes, peak load demands, regulation of the power system and power system emergencies.
In 1982, Reclamation began the Glen Canyon Environmental Studies program in response to concerns that changes to the resources downstream of Glen Canyon Dam on the Colorado River were occurring as a result of dam and powerplant operations. The information obtained from the studies led the Secretary to direct Reclamation in 1989 to begin preparation of an environmental impact statement (EIS) on the operation of Glen Canyon Dam. Also, preparation of an EIS and long term monitoring was specifically required by the Grand Canyon Protection Act of 1992. Following preparation of the EIS, the Secretary signed the Record of Decision (ROD) in October, 1996.
The ROD provided additional criteria affecting the operation of Glen Canyon Dam and constrained the operation of the powerplant by restricting flows and reducing flexibility. The capacity of the powerplant was restricted except when responding to power system emergencies thus limiting the amount of generation during peak hours and forcing more generation during non-peak hours. As part of the ROD, the Adaptive Management Program was developed to provide an organization and process for cooperative integration of dam operations, downstream resources protection and management, and monitoring and research information, as well as to improve the values for which the Glen Canyon National Recreation Area and Grand Canyon National Park were established.
In December 2006, Reclamation began preparation of an EIS for adoption of a Long Term Experimental Plan for the operation of Glen Canyon Dam and other associated management activities. The purpose of the Long Term Experimental Plan was to increase understanding of the ecosystem downstream from Glen Canyon Dam and to improve and protect downstream resources. The plan would consider dam operations, modifications to Glen Canyon Dam intake structures to modify water temperature, and other non-flow management actions, such as removal of non-native fish species.
On February 12, 2008, Reclamation issued a Federal Register Notice putting the Long-Term Experimental Plan EIS on hold pursuant to embarking on a five-year (2008-2012) experiment identified in an environmental assessment and biological opinion released in February 2008.
Since the Glen Canyon environmental studies began in 1983 and through 2006, Reclamation and Western together have spent an estimated $249,400,000 of revenue received from the sale of CRSP power to fund studies, perform experiments, purchase power and monitor the Glen and Grand Canyons relative to the operation of Glen Canyon Dam.
New challenges are also arising as drought has impacted the Colorado River. The seven-year period from 2000 to 2006 was the driest seven-year period in 100 years of record keeping. The drought prompted the Secretary to request the seven Colorado River Basin states and Reclamation to establish guidelines and coordinated management strategies for the operation of Lake Powell and Lake Mead under low reservoir conditions. On December 13, 2007, the Secretary signed an historic decision implementing new interim operational guidelines that established rules for shortages, surpluses, and coordination of operations between Lake Powell and Lake Mead, and encourage new initiatives for water conservation.The day to day operation and maintenance of Glen Canyon Dam and Powerplant are performed by employees of the Glen Canyon Field Division of the Power Office and are funded from revenue received from the sale of CRSP power. The powerplant, consisting of eight hydroelectric generating units with a combined capacity of 1,320 megawatts, is a significant part of the CRSP power resources with 79 percent of the total CRSP capacity. The capacity of the generating units has been increased from the original capacity through the application of new technology and other work performed in the powerplant as repair or replacement of equipment occurred due to normal “wear and tear” and aging. For the period from 1965 to 2010, the average annual generation from the Glen Canyon Powerplant was 4,610,523,000 kilowatt-hours which is enough electricity to supply the annual needs of about 400,000 households.