Difference between revisions of "GCDAMP Glen Canyon Dam"

Glen Canyon Monthly Operational Call

The DOI also will conduct monthly Glen Canyon Dam operational coordination meetings or calls with the DOI bureaus (USGS, NPS, FWS, BIA, and Reclamation), WAPA, AZGFD, and representatives from the Basin States and the UCRC. Each DOI bureau will provide updates on the status of resources and dam operations. In addition, WAPA will provide updates on the status of the Basin Fund, projected purchase power prices, and its financial and operational considerations. These meetings or calls are intended to provide an opportunity for participants to share and obtain the most up-to-date information on dam operational considerations and the status of resources (including ecological, cultural, Tribal, recreation, and the Basin Fund). One liaison from each Basin State and from the UCRC will be allowed to participate in the monthly operational coordination meetings or calls. [1]

• June 2025 Operations call
• May 2025 Operations call
• April 2025 Operations call
• March 2025 Operations call
• February 2025 Operations call
• January 2025 Operations call
• December 2024 Operations call
• November 2024 Operations call
• October 2024 Operations call
• September 2024 Operations call
• August 2024 Operations call
• July 2024 Operations call
• June 2024 Operations call

Archived Glen Canyon Monthly Operations Call slides

USBR Monthly/Annual Reports

• Upper Colorado Region Water Operations site
• 24-Month Study
• Monthly Summaries
• Annual Operating Plans for Colorado River reservoirs

Reclamation’s Upper Colorado Region Water Office makes monthly water release schedules in acre-feet for Glen Canyon based upon anticipated inflows to the lake, release requirements to the lower basin and storage targets for the lake. This monthly water schedule is passed on to Western’s Resource Scheduling Office in Montrose, CO. Western’s scheduling office then develops an hourly release schedule. This schedule takes into account Glen Canyon ROD requirements and the requirements and agreements made by Western and Reclamation regarding the operation of the other CRSP powerplants. Western’s dispatch office in Phoenix, Arizona then provides Reclamation’s Glen Canyon Power Operations Center with a daily, 24 hour operating schedule, identifying Western’s desired hourly electric power schedule (in megawatts). This schedule is then put into the computer system at Glen Canyon by Reclamation (2). This schedule then becomes the megawatt quantities which are targeted during the “real time” operation at Glen Canyon Dam.

The Glen Canyon Power Operations Center operators utilize the generation schedule supplied by Western to operate the generating units while giving consideration to efficiency and equipment characteristics. In addition, the generators automatically respond to a “regulation signal” developed and electronically transmitted to the dam by Western for continuous response to power system load and frequency changes. (This is further described later in this paper). [2]

Shortly after Interim Flows began (August , 1991), Western met with staff at the Glen Canyon Environmental Studies (GCES) and with other Reclamation representatives. Western requested flexibility in order to regulate an electrical control area. This resulted in an agreement whereby Western was allowed to fluctuate 10% around any operational constraint and that Western would meet with GCES staff monthly to discuss any operational issues that surfaced. Thus, the Interim Flow downramp requirement of 1,500 cfs could be as high as 1,650 cfs and still be in compliance (1,500 cfs + 150 cfs).

After the ROD and Operating Criteria were signed, Western and Reclamation negotiated a MOU to more fully detail operational issues. Reclamation was interested in changing the 10% band width because it believed that the ROD and Operating Criteria didn’t specify that kind of flexibility. Instead, Western was allowed to use up to 1,000 cfs for regulation purposes. Compliance was to be monitored by SCADA using a one hour integrated value. It was thought that, even though a downramp at any one moment of time could be as high as 2,500 cfs (1,500 cfs + 1,000 cfs), it would be uncommon for the downramp to exceed 1,500 cfs since this is recorded as an integrated value over the hour. [3]

The EIS identified Emergency Exception Criteria as common elements in all alternatives. They are defined in the EIS as follows (3):

“Normal operations described under any alternative would be altered temporarily to respond to emergencies. NERC has established guidelines for the emergency operations of interconnected power systems. . . . Examples of system emergencies include:

• Insufficient generating capacity
• Transmission system: overload, voltage control, and frequency
• System restoration
• Humanitarian situations (search and rescue)”

When emergency exception criteria are invoked, normal operations are suspended until the emergency has ended, or Western has discharged its North American Energy Reliability Council (NERC) responsibility regarding the emergency. Emergency exception criteria are further defined in the operating criteria and in the MOU on Glen Canyon operations signed by Western and Reclamation.

It was the invocation of emergency exception criteria on April 1st, 1998 which piqued the interest of some AMWG members in Reclamation and Western’s interpretation of the ROD.[4]

Both emergency exception criteria and regulation have been described in this paper. Recently, some members of the AMWG and TWG have focused their concerns and discussion on “emergencies”. However, the issue at hand and the subject of this paper is regulation. It is largely regulation that has resulted in the occasional exceedence of the 1,500 cfs downramp.[5]

It does not seem reasonable that the ROD was intended to require either: 1) the exclusion of Glen Canyon Dam from participating in regulating a load control area, or 2) participation in regulating a load control area but limiting hourly load following to 500 cfs downramp (or something like it). Further, the environmental impact of regulation appears to be minimal, based on a review of the flows at the Lee Ferry gage. Finally, it has become clear to Reclamation and Western that precise and inviolate control of water releases from Glen Canyon Dam is beyond the capabilities of the machinery and electronic controls. For these reasons, Reclamation and Western intend to impose the following changes:

• Limit scheduled down ramps to 1,450 cfs (rather than 1,500),
• Employ the use of SCADA table in the preparation of Western’s hourly schedules,
• Investigate the transfer of a portion of the “ACE” to other CRSP powerplants,
• Move the ACE signal back to Glen Canyon Dam (i.e. return “regulation” to the dam) once it has been demonstrated that the ACE will not cause “routine” excedences,
• Work with the AMWG to determine the proper level of analysis required to address the potential downstream impacts of regulation in Glen and Grand Canyons,
• Educate all interested parties on the power system and equipment operations and the associated results to water releases at the dam,
• Add release data to Western’s web site and provide periodic reports to the TWG on the operation of Glen Canyon Dam and,
• Continue efforts to for better coordination between Reclamation and Western regarding the scheduling and operation of Glen Canyon Dam.[6]

The back of Glen Canyon Dam as Lake Powell was filling showing the 8 penstocks on the right and the two river outlet works on the left.

Report to Congress Regarding Operations of Glen Canyon Dam[7]

• Report to Congress - Water Year 2020-2021
• Report to Congress - Water Year 2019-2020
• Report to Congress - Water Year 2018-2019
• Report to Congress - Water Year 2017-2018
• Report to Congress - Water Year 2016-2017
• 2015-2016 Report to Congress
• 2014-2015 Report to Congress
• 2013-2014 Report to Congress
• 2010-2011 Report to Congress
• 1999-2001 Report to Congress
• 1998-1999 Report to Congress

• Glen Canyon Dam Interim Low Elevation Operational Guidance
• 2017 Operating Criteria for Glen Canyon Dam
• 2016 LTEMP Record of Decision (ROD)
• 2016 LTEMP EIS Final Draft (FEIS)
• 2007 Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead
• 1997 Operating Agreement between Reclamation and WAPA regarding the Operation of Glen Canyon Dam
• 1997 Operating Criteria for Glen Canyon Dam
• Operations of Glen Canyon Dam under the 1996 ROD
• 1996 Record of Decision on the Operation of Glen Canyon Dam
• 1996 EIS on the Operation of Glen Canyon Dam
• 1980 memo: Transfer of Functions and Property at Glen Canyon Dam from Reclamation to WAPA
• The Colorado River Basin Project
• Law of the River Overview

2025

2024

• Operation Planning Updates

2023

2022

2021

2020

• Review of the Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead

2019

2018

• Urban Waterfronts 2018

2017

• Analysis of Water Losses and Impacts to the Grand Canyon Ecosystem of the "Fill Mead First" Proposal
• Fill Mead First: A technical assessment (Summary)
• Fill Mead First: A technical assessment (Analysis)

2016

• August 2016 DOI-DOE Federal Family call on Glen Canyon Operations
• Glen Canyon Dam operations during equalization

2015

• 2016 Annual Operating Plan
• Panel on Current Projects and Issues in Utah
• Central Utah Project
• Meeting the Mitigation Requirement for the Bonneville Unit CUP
• Current Projects and Issues in Utah
• Provo Area Office

2014

• Colorado River Annual Operating Plan and Drought Contingency Planning
• DOI-DOE Hydrograph Development for Water Year 2015
• Panel on the Potential Effects of Long-Term Drought on Colorado River Operations
• Near Term Risks: Options to Address Declining Reservoirs
• State of Nevada Concerns

2013

• Water Year 2014 Hydrograph
• Colorado River Basin Hydrology and Projected Glen Canyon Dam Operations
• Glen Canyon Dam Facility Management

2012

• Water Year 2013 Hydrograph
• TWG Report: 2013 Hydrograph
• DOI and DOE Operating Hydrograph Recommendations for GCD (2012 water year)
• Water Year 2013 Hydrograph TWG Motion
• 2013 Hydrograph Development
• FY2013 Hydrograph (from 8/2011 AMWG meeting)

2011

• 2012 Hydrograph
• 2012 Hydrograph Development
• Department of the Interior and Department of Energy Operating Hydrograph Recommendations for Glen Canyon Dam (2012 Water Year), June 6, 2011
• WY2012 Hydrograph Development
• 2012 Hydrograph Development
• Grand Canyon Trust Proposed FY2012 Hydrograph
• Bureau of Reclamation Updates

2010

• Fiscal Year 2011-12 Hydrograph and E-mail Message to the AMWG from Anne Castle Dated July 23, 2010, Subject: July 23 Final Draft DOI-DOE Proposed Hydrograph Recommendations
• Department of the Interior and Department of the Energy Recommendations for Glen Canyon Dam with August 23, 2010, edits
• Grand Canyon Protection Act
• Report on Modeling the 2008-2010 Period to Support Development of the 2011 Hydrograph
• Proposed Water year 2011 Hydrograph: Impacts on CRSP Electric Power Resources
• Grand Canyon Trust Hydrograph Proposal
• Figure 1, AOP, BOR, AMWG monthly volumes

2009

• FY2010-11 Draft Budget, Worplan, and Hydrograph

2006

• Hazel et al. 2006. Stage-Discharge Relations for the Colorado River in Glen, Marble, and Grand Canyons, Arizona: U.S. Geological Survey Open-File Report 2006-1243, 7 p

2004

• ***DRAFT*** Evidence for the Failure of the Modified Low Fluctuating Flow Alternative (MLFFA) to Benefit Most Ecological Resources in Grand Canyon

2003

• Topping et al. 2003. Computation and analysis of the instantaneous-discharge record for the Colorado River at Lees Ferry, Arizona, May 8, 1921 through September 30, 2000: U.S. Geological Survey Professional Paper 1677, 118 p.

Minimum flows:

• 8,000 cfs between 7 a.m. and 7 p.m.
• 5,000 cfs between 7 p.m. and 7 a.m.

Maximum non-experimental flows:

• 25,000 cfs

Daily range:

• 5,000 for monthly volumes <600 kaf
• 6,000 for monthly volumes 600– 800 kaf
• 8,000 for monthly volumes >800 kaf

Ramp rates:

• 4,000 cfs/hr up
• 1,500 cfs/hr down

How much water can be released at Glen Canyon Dam?

• 8 generators = 4,000 cfs each = 32,000 cfs
  (note that there is usually one or two generators down for maintenance at any given time)
• 4 bypass tubes = 3,750 cfs each = 15,000 cfs
• 2 spillways = up to 208,000 cfs [9]

Critical water elevations

• 3715' = dam crest elevation
• 3700' = top of spillway gates (3704' with plywood flashboards)
• 3648' = spillway crest elevation
• 3490' = minimum power pool (to prevent cavitation in the penstocks)
• 3470' = penstock elevation (this is the centerline elevation, the penstocks are 15' in diameter)
• 3374' = bypass tube elevation (this is the centerline elevation, the bypass tubes are 8' in diameter)
• 3370' = reservoir deadpool elevation [10]

How fast do water and waves flow down the Grand Canyon?

• The Colorado River in Grand Canyon: How Fast Does It Flow?

Discharge waves move downstream faster than the water. For example, in May 1991, the discharge waves produced by rapidly changing dam releases moved through the canyon in about 1 2/3 days, whereas the water took about 4 1/3 days to travel the 235 miles from Lees Ferry to Gneiss Canyon (RM 235.7).

• Tide Tables

Video of the construction of Glen Canyon Dam

• HOW ITS MADE - The Glen Canyon Dam

1983 flood videos and spillway repairs

• Challenge at Glen Canyon (Part 1)
• Challenge at Glen Canyon (Part 2)
• Challenge at Glen Canyon (Part 3)