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Citizen and Professional Science in Glen Canyon National Recreation Area
November 01, 2021
A HISTORY of citizen and professional science related to significant low reservoir levels at Glen Canyon National Recreation Area (Lake Powell).
After observing 60-years of reservoir management at Lake Powell, we present the following contradictions that have emerged:
(1) The original name was Glen Canyon Reservoir and the filling criteria began in March of 1963. The name was formally changed to Lake Powell when Lady Bird Johnson dedicated the facility for the people of the 50 United States in 1966. It required 17-years to finally fill Lake Powell, which occurred in Year 1980. The decades of the 1980s and 1990s were significantly wetter than previous decades, and interupted by a four-year dry cycle between 1989 and 1992. By 1992 the reservoir capacity had dropped to 50%. This condition occurred again in 2002 and, by March of 2005, the capacity dropped to 35%, which then launced the development of an Environmental Impact Statement called "Shortage Criteria" and finalized as 2007 Interim Guidleines.
(2) A brim full reservoir, as occurred from 1983 to 1988 and from 1995 to 2000, essentially means there was no flood control capacity in the Colorado River Basin. This is a variance to the principles set forth in the Boulder Canyon Project Act of 1928, which mandated flood control as the primary management priority. It must be understood that if something goes wrong with the structural integrity of Glen Canyon Dam, and it becomes necessary to vacate the reservoir of water as quickly as possible to avoid a catastrophe, that it would take about 12 months to complete the evacuation process. This means that dam safety is dependent upon perfect performance at all times and under all conditions. Yet, no human endeavor has ever matched the power of nature.
This clearly indicates that Reclamation manages Lake Powell for water storage and hydropower, which are the secondary and tertiary management priorities. This is why the snowmelt of 1983 became an emergency situation at Glen Canyon Dam and caused by a reluctance to vacate the reservoir to safely accommodate inflows of 111,500 cfs (Burgi, 1984) and a 4-month snow melt volume of 15 million acre-feet. It is now reasonable to conclude that, had the volume been a five-month snow melt of 30 million acre-feet, as in 1884, Glen Canyon Dam would have been breached by the Colorado River (Swain, 2002).
(3) One of the incidental purposes of Lake Powell is to settle and store entrained sediment and organic detritus. When Lake Powell elevations are low the stored sediment and organic detritus is mobilized by the Colorado River and carried further downstream toward Glen Canyon Dam (Pratson, 2008); this shortens the lifespan of this dam. This includes the stored sediment in the 125 side canyons, many of which are in close proximity of Glen Canyon Dam, such a Wahweap and Antelope canyons. When the sediment load in Lake Powell reaches 50%, the priority objectives of flood control and water storage are compromised (USGS, 1960). Or, when sediment reaches the elevation of the outlet tubes on the front face of Glen Canyon Dam, a dredging program must begin (Schultz, 1961). A reservoir losing storage capacity to sediment fill is the same as depleting the capacity of an aquifer to zero. You end up with nothing.
(4) Erosion by a flowing Colorado River over exposed reservoir sediment mobilizes decaying organic matter and this becomes a water quality issue, especially for the aquatic species of the reservoir, and the aquatic species below Glen Canyon Dam. This would also be true for Hoover Dam and Lake Mead. The decay process of the organics decreases oxygen levels in the water column of the reservoir, and the odors of hydrogen sulfide emissions are most unpleasant, and the emissions of raw methane gas (odorless) from Lakes Powell and Mead does load the atmosphere with a significant greenhouse gas contribution (Dohrenwend, see presentations below). See: Hydropower is likely to have no future on the Colorado. OTC.
SATELLITE IMAGERY & MAPS
A CHRONOLOGY OF SCIENCE IN GCNRA
HUMAN HISTORY ASSETS
1950 to 1993: Kent Frost; professional land and river guide.
1952 to 1956: George Simmons (USGS employee) and several colleagues.MAPS: USGS; 1923; baseline data and observations before reservoir inundation
Simmon's Trip Diaries
BUREAU OF LAND MANAGEMENT (BLM)
Glen Canyon National Recreation Area (Lake Powell)
Utah BLM: Circa 2017
1992 to 2004: Dr. Robert H. Webb (USGS), Dr. Jayne Belnap (USGS), and John Weisheit (professional guide).
2002 to 2006: Dr. John Dohrenwend (USGS) & John Weisheit
2017 to present: The Returning Rapids Project; Mike DeHoff (Principal Investigator) and colleagues
2021 to present: Glen Canyon Rejuvenation Project; Dr. Dan McCool and colleagues
Aerial Photos: Light Hawk Overflight of September 10, 2021.
2021 to the present: Tom Martin (River Runners for Wilderness) and John Weisheit (Living Rivers & Colorado Riverkeeper).
Dirty Devil Boat Ramp to Bullfrog Creek Boat Ramp
Note: Portfolios; files reduced; takes awhile to download.
The Repeat Photos
Stay tuned for a more detailed narratives that will include landscape and aerial photos.
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