November 2012 High-Flow Experiment
Rm 45 before 3/4/2008 (top) & after 3/14/2008 high-flow. U.S. Geological Survey Photos here. --- News Release here. The goal of the high-flow experiment was to move sand stored in the river channel and redeposit it to rebuild eroded sandbars and beaches downstream of the Paria River in Grand Canyon National Park. This release followed the science-based Protocol for High-Flow Experimental Releases from Glen Canyon Dam established in May 2012 and is a component of the Department's compliance with the Grand Canyon Protection Act of 1992. The Grand Canyon Protection Act mandates that Glen Canyon Dam be operated in a manner that protects, mitigates adverse impacts to, and improves the values for which Grand Canyon National Park and Glen Canyon National Recreation were established. Flow Information (download schedules by clicking on the graphics below) 
Flow arrival times downstream in Grand Canyon may be downloaded as a table (left) or in map form (center). The release schedule at Glen Canyon Dam is also available (right). Click on the graphic(s) above that you would like to download. (PDF format)
At the start of the HFE on Sunday, November 18, the flow increased from 9,000 cfs by 1,500 cfs per hour for 22 hours until it reached the peak release flow of approximately 42,000 cfs. The peak release was held for 24 hours. Flows ramped down at a rate of 200 cfs per hour to 31,300 cfs, then continued down ramping at 1,000 and 1,500 cfs per hour until a base release of 9,000 cfs was reached. The total duration of the experiment from beginning to end was approximately five days . Because of the distances downstream of the dam, increasing flows reached downstream locations at different times. Flows arrived at Phantom Ranch (River Mile 87) about 16 hours after release from Glen Canyon Dam, and almost two days after release at Pearce Ferry (River Mile 279). Specific information about flow levels at varying locations within Grand Canyon was posted before and during the high-flow experiment at Lees Ferry, Phantom Ranch, Pipe Creek, Backcountry Information Center and visitor centers. Here is a link to the Bureau of Reclamation's 2012 High-Flow website. Current flow at Lees Ferry: http://waterdata.usgs.gov/usa/nwis/uv?09380000 
River users and backpackers can use these maps to determine which campsites provide the most camping area at high flow. Camp on Durable Surfaces 
Please do not camp in the pre-dam old high-water zone. Camps should not be established in the pre-dam old high-water zone, which is marked by mesquite, catclaw acacia, and netleaf hackberry on rounded sandy slopes or higher sand terraces.
View more chapters of the park's non-commercial river trip orientation video here or on YouTube
Glen Canyon Dam with tubes open during the 2008 high-flow. The high-flow protocol is a framework for using dam operations to release high flows following tributary deposits of new sand into the main channel of the Colorado River. It was developed by the Department of the Interior pursuant to the National Environmental Policy Act based on the best available scientific information developed through the Glen Canyon Dam Adaptive Management Program and other sources of information. The protocol builds on a wealth of scientific knowledge gained from more than 16 years of extensive scientific research, experimentation, and analysis, including analysis of a series of previous high-flow experimental releases in 1996, 2004, and 2008. The protocol is intended to provide additional data essential to inform and refine future management decisions for the management of the Colorado River through 2020. 
Humpback chub Colorado River sandbars within the Grand Canyon provide habitat for wildlife, serve as camping beaches for recreationists, and supply sand needed to protect archaeological sites. High flows may also create backwater areas used by young native fishes, particularly the endangered humpback chub.
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Did You Know?
From Yavapai Point on the South Rim of the Grand Canyon, the drop to the Colorado River below is 4,600 feet (1,400 m). The elevation at river level is 2,450 feet (750 m) above sea level. Without the Colorado River, a perennial river in a desert environment, the Grand Canyon would not exist.