Modeling the impacts of Glen Canyon Dam operations on downstream Colorado River resources Active
USGS Southwest Biological Science Center's Grand Canyon Monitoring and Research Center leadership and PIs prepared a cooperator publication and a presentation that report on modeling results to evaluate potential effects of reservoir management on various resources in Lake Powell and Grand Canyon.
The Report
The Bureau of Reclamation (Reclamation) is writing two supplemental Environmental Impact Statements and a new Environmental Impact Statement (EIS) that will analyze the effects of changing water flow out of Glen Canyon Dam. These actions have the potential to affect downstream resources, including threatened and endangered species, in the Grand Canyon. This report covers modeling support provided on the two sEIS by the USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center (GCMRC). The first sEIS (Interim Guidelines sEIS) modifies Reclamation’s 2007 Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead that determines annual water releases from Glen Canyon Dam based on inflow to Lake Powell, the power generating requirements of Glen Canyon Dam, and relative lake levels of Lake Powell and Lake Mead. Drought conditions have lowered the level of Lake Powell and may require Glen Canyon Dam to release less water than was analyzed in the Interim EIS (7-million-acre feet/year). The effect of less water released, as well as lower lake levels and associated water quality concerns on downstream resources was not analyzed in the 2007 Interim Guidelines EIS. Reclamation requested GCMRC science support to provide models predicting the effects to resources of water releases lower than 7M acre feet/year, including models predicting effects to threatened and endangered species for use in a Biological Assessment.
The report was published by Reclamation on April 9, 2024, and can be accessed at: https://www.usbr.gov/uc/progact/amp/pdfs/LTEMP/20240408-ModelingImpactsGlenCanyonDamOperationsColoradoRiverResources-508-UCRO.pdf
More information about the Glen Canyon Adaptive Management Program can be accessed at: https://www.usbr.gov/uc/progact/amp/index.html
The Presentation
The presentation was shared at a public Glen Canyon Adaptive Management Group Meeting on January 31, 2024, to support preparation of the upcoming Draft Long-term Experimental and Management Plan (LTEMP) Supplemental Environmental Impact Statement (SEIS).
To access the presentation, click the link below:
Citations:
Yackulic, C.B., Bair, L.S., Eppehimer, D.E., Salter, G.L., Deemer, B.R., Butterfield, B.J., Kasprak, A., Caster, J.J., Fairley, H.C., Grams, P.E., Mihalevich, B., Palmquist, E.C., and Sankey, J.B., 2024, Modeling the impacts of Glen Canyon Dam operations on Colorado River resources: Phoenix, Ariz., U.S. Department of Interior, Bureau of Reclamation, cooperator publication prepared by U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, Ariz., April 2024, 133 p., https://www.usbr.gov/uc/progact/amp/pdfs/LTEMP/20240408-ModelingImpactsGlenCanyonDamOperationsColoradoRiverResources-508-UCRO.pdf
Yackulic, C.B., Bair, L.S., Eppehimer, D.E., Salter, G.L., Butterfield, B.J., Caster, J.J., Deemer, B.R., Fairley, H., Grams, P.E., Kasprak, A., Palmquist, E.C., and Sankey, J.B., 2024, Modeling the impacts of Glen Canyon Dam operations on Colorado River resources [presentation], LTEMP SEIS meeting (virtual), January 31, 2024: Flagstaff, Ariz., US Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, https://www.usgs.gov/centers/southwest-biological-science-center/science/modeling-impacts-glen-canyon-dam-operations
The data in the presentation are preliminary or provisional and are subject to revision. They are being provided to meet the need for timely best science. The data have not received final approval by the U.S. Geological Survey (USGS) and are provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the data.
Grand Canyon Monitoring and Research Projects
USGS Southwest Biological Science Center's Grand Canyon Monitoring and Research Center leadership and PIs prepared a cooperator publication and a presentation that report on modeling results to evaluate potential effects of reservoir management on various resources in Lake Powell and Grand Canyon.
The Report
The Bureau of Reclamation (Reclamation) is writing two supplemental Environmental Impact Statements and a new Environmental Impact Statement (EIS) that will analyze the effects of changing water flow out of Glen Canyon Dam. These actions have the potential to affect downstream resources, including threatened and endangered species, in the Grand Canyon. This report covers modeling support provided on the two sEIS by the USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center (GCMRC). The first sEIS (Interim Guidelines sEIS) modifies Reclamation’s 2007 Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead that determines annual water releases from Glen Canyon Dam based on inflow to Lake Powell, the power generating requirements of Glen Canyon Dam, and relative lake levels of Lake Powell and Lake Mead. Drought conditions have lowered the level of Lake Powell and may require Glen Canyon Dam to release less water than was analyzed in the Interim EIS (7-million-acre feet/year). The effect of less water released, as well as lower lake levels and associated water quality concerns on downstream resources was not analyzed in the 2007 Interim Guidelines EIS. Reclamation requested GCMRC science support to provide models predicting the effects to resources of water releases lower than 7M acre feet/year, including models predicting effects to threatened and endangered species for use in a Biological Assessment.
The report was published by Reclamation on April 9, 2024, and can be accessed at: https://www.usbr.gov/uc/progact/amp/pdfs/LTEMP/20240408-ModelingImpactsGlenCanyonDamOperationsColoradoRiverResources-508-UCRO.pdf
More information about the Glen Canyon Adaptive Management Program can be accessed at: https://www.usbr.gov/uc/progact/amp/index.html
The Presentation
The presentation was shared at a public Glen Canyon Adaptive Management Group Meeting on January 31, 2024, to support preparation of the upcoming Draft Long-term Experimental and Management Plan (LTEMP) Supplemental Environmental Impact Statement (SEIS).
To access the presentation, click the link below:
Citations:
Yackulic, C.B., Bair, L.S., Eppehimer, D.E., Salter, G.L., Deemer, B.R., Butterfield, B.J., Kasprak, A., Caster, J.J., Fairley, H.C., Grams, P.E., Mihalevich, B., Palmquist, E.C., and Sankey, J.B., 2024, Modeling the impacts of Glen Canyon Dam operations on Colorado River resources: Phoenix, Ariz., U.S. Department of Interior, Bureau of Reclamation, cooperator publication prepared by U.S. Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, Flagstaff, Ariz., April 2024, 133 p., https://www.usbr.gov/uc/progact/amp/pdfs/LTEMP/20240408-ModelingImpactsGlenCanyonDamOperationsColoradoRiverResources-508-UCRO.pdf
Yackulic, C.B., Bair, L.S., Eppehimer, D.E., Salter, G.L., Butterfield, B.J., Caster, J.J., Deemer, B.R., Fairley, H., Grams, P.E., Kasprak, A., Palmquist, E.C., and Sankey, J.B., 2024, Modeling the impacts of Glen Canyon Dam operations on Colorado River resources [presentation], LTEMP SEIS meeting (virtual), January 31, 2024: Flagstaff, Ariz., US Geological Survey, Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, https://www.usgs.gov/centers/southwest-biological-science-center/science/modeling-impacts-glen-canyon-dam-operations
The data in the presentation are preliminary or provisional and are subject to revision. They are being provided to meet the need for timely best science. The data have not received final approval by the U.S. Geological Survey (USGS) and are provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the data.