Frequently Asked Questions
1) Is it possible to improve the downstream ecosystem with the Glen Canyon Dam still in place?
This is what the Adaptive Management Program is intended to accomplish. Glen Canyon Dam provides vitally important water and power generation benefits to society so the goal of the Adaptive Management Program is to determine how the dam can be re-operated to protect and improve the many natural and cultural resouces downstream. This is a long-term process that requires gaining the most accurate scientific information to make managment decisions.
2) What progress has the Adaptive Management Program made toward its goals?
Significant progress has been made in two areas: 1) Working relationships among a diverse group of stakeholders has been established as well as a collaborative program for using the best scientific data to make recommendations to the Secretary of the Interior on satisfying the directives of the Grand Canyon Protection Act; 2) A functional science center is in place capable of delivering the latest and most relevant scientific information for management decisions.
3) When will there be another controlled flood to restore beaches?
When conditions of science are met and the main river channel immediately below the confluence with the Paria River has been sufficiently enriched with accumulations of fine sediment, the AMWG may propose additional high flow tests to improve backwater habitats for endangered fish, camping beaches and sandbars in the Grand Canyon.
4) How much power is Glen Canyon Powerplant capable of producing?
GCD has a power plant with eight generators with a combined operational capacity of 1320 megawatts (MW). On an average annual basis, it generates enough energy to supply 425,000 households with electricity for one year and is equivalent to 2.5 million tons of bituminous coal. Its electrical power generation is connected to an electrical transmission grid, which is tied to the other CRSP power plants and to other private and publicly owned power plants. The powerplant has a maximum release capacity of approximately 32,000 cubic feet per second (cfs). The dam has river outlet works and two spillways, which also can be used to release water.
5) Where does the power produced by Glen Canyon Power Plant go?
Power generated at Glen Canyon Dam is sold under 20-year contracts within the states of Arizona, Colorado, Nevada, New Mexico, Utah, and Wyoming. CRSP power is sold to non-profit entities who serve over five million customers.
6) What happens to the revenues from the sale of CRSP power?
Revenues from the sale of CRSP power are deposited in the U.S. treasury and are used to fund Glen Canyon Dam's construction costs (including interest), irrigation assistance, operation and maintenance costs, salinity control, and environmental programs. Since 1983, CRSP power revenues have funded over $225 million of costs associated with environmental programs in the Grand Canyon. Since 2000, environmental experiments at Glen Canyon Dam recommended through the AMP cost an additional $33.5 million.
7) Is hydropower production affected by the AMP?
The Glen Canyon Dam Adaptive Management Program can affect hydropower production at Glen Canyon Dam. The intent of the AMP is to improve the resources downstream of Glen Canyon Dam, recognizing that hydropower is an integral component of the region's economy. Since 1991, operations have been changed at Glen Canyon Dam to address environmental concerns, reducing electricity generation by about one-third. This reduction in electricity must be purchased from other generating resources (such as coal, thermal, gas, nuclear) and paid for by CRSP customers.
8) What happened to the people who once lived at the archaeological sites in the canyons?
Contrary to popular portrayal, the people who lived at the archaeological sites did not "vanish." Their descendants are still among us, comprising the Native American tribes that exist today. Through time, people respond to the social and environmental factors acting on them. When conditions in one location change for one reason or another, people move on to new locations or join with other groups. The Southwest has and continues to be very dynamic when it comes to human habitation.
9) Why do the tribes care about Grand Canyon and its resources?
The tribes consider Grand Canyon to be very important to their history. It's in their origin narratives, was a place where their ancestors lived, and for some of the tribes, it is a part of their current reservation land. Similarly, the resources in Grand Canyon maintain a traditional cultural importance. They have been used as foods, medicines, ceremonial items, craft materials, housing, and for a multitude of other purposes. They are the basis of traditional ways of life in tribal cultures. Even though modern society has reduced tribes' day-to-day dependence on some of these resources, their importance to the tribal cultures nevertheless remains intact.
10) How might threatened and endangered species be affected by dam operations?
Damming the Colorado River has changed the way water courses and pulses through Grand Canyon. Much of the sediment that the river naturally carries is trapped behind Glen Canyon Dam. Water released from the dam is colder than historical temperatures. Reduced temperatures changed the prey base available to native fishes and altered their spawning productivity and survival in the mainstem river while it favored cold water non-natives that prey upon and compete with native fishes. Daily water level fluctuations below the dam inundated and dried near-shore habitat that supported native fishes and the Kanab ambersnail. Reduced sediment loads interrupted the rejuvenation of warm, still backwater habitat and depleted beaches needed for the growth of riverside riparian vegetation. Attenuation of seasonal flood cycles altered the hydrological cleansing and rejuvenation needed to sustain native riparian habitat essential to southwestern willow flycatcher nesting.
11) How does the Adaptive Management Program address threatened and endangered species?
A driving force for developing an adaptive management program for the operation of Glen Canyon Dam was a 1978 determination that dam operations were jeopardizing the survival of the endangered humpback chub. Since then, strides have been made to better understand how operation of the dam affects the ecosystem upon which threatened and endangered species rely, and modifying dam operations to accommodate these and other species.
Timed, simulated floods have been conducted to transport sediment into Grand Canyon to assist in restoring backwater habitats and regenerate riparian areas. Widely fluctuating daily flow pulses have been reduced to stabilize near-shore habitat. Design and feasibility studies are underway for a selective withdrawal structure on the dam that will allow dam operators to control the temperature and oxygen content of water released into the Colorado River. Experimental removal of non-native fishes near downstream native fish spawning and rearing areas has shown early success in reducing competitive and depredation pressure from native fishes while maintaining sought-after sportfishing 60 miles upstream.
12) Is the Adaptive Management Program a recovery program for threatened and endangered species?
A goal of the AMP is to be consistent with the Endangered Species Act, yet it is not intended to serve as an endangered species recovery program. Full restoration of the pre-dam ecosystem and annual and seasonal river flows and temperatures are not objectives for the AMP. However, efforts to regain the function of the river and its ecological attributes so that the most disadvantaged species along the river are not jeopardized with extinction are commendable goals and are required under the Endangered Species Act. Some of these efforts are derived or supported by action items contained in species recovery plans. As these efforts stabilize and improve the status of threatened and endangered species, they are assisting species recovery.
13) What is the Lees Ferry Trout Fishery ?
The Lees Ferry trout fishery is a 15.5-mile stretch of the clear-flowing Colorado River immediately below Glen Canyon Dam in Glen Canyon National Recreation Area. The trout fishery was established through stocking shortly after the completion of the dam because of the suitability of the cool, clear water for trout. With temperatures ranging from 46 to 60 degrees F and a good supply of aquatic foodstuffs, the Lees Ferry trout fishery is a renownded blue-ribbon fishery that draws anglers from around the world. The Arizona Game and Fish Department manages the trout fishery to provide high quality fishing opportunities in a unique recreational setting.
The trout fishery takes its name from "Lees Ferry", the historic crossing point of the river approximately 15.5 miles below the dam named after John D. Lee who operated a cable ferry from here.
14) Where are the core populations of humpback chub located in relation to the trout fishery?
The area managed for recreational trout fishing, occupies the first 15.5 miles of the Colorado River below Glen Canyon Dam. The confluence of the Little Colorado River and the Colorado River, which is a critical area for humpback chub, is located deep in the Grand Canyon approximately 60 miles downstream from Lees Ferry. Here, efforts are being made under the Adaptive Management Program to conserve and enhance humpback chub populations, including the removal of non-native trout.
15) Do dam operations affect the trout fishery?
Yes. Minimum flows and the range of flow fluctuation can influence the hatching of trout eggs and the survival of young trout, and can influence the amount of food and habitat available to trout in the upper reach of the river. Additionally, factors associated with the lake above the dam can also affect trout, including the water temperature and amount of dissolved oxygen in the water.