Hydrology

Upper Colorado River Basin Hydrology Upper Colorado River Basin regularly experiences significant year to year hydrologic variability. During the 21-year period 2000 to 2020, however, the unregulated inflow to Lake Powell, which is a good measure of hydrologic conditions in the Colorado River Basin, was above average in only 4 out of the past 19 years. The period 2000-2020 is the lowest 21-year period since the closure of Glen Canyon Dam in 1963, with an average unregulated inflow of 8.62 maf, or 80 percent of the 30-year average (1981-2010). (For comparison, the 1981-2010 total water year average is 10.83 maf.) The unregulated inflow during the 2000-2020 period has ranged from a low of 2.64 maf (24 percent of average) in water year 2002 to a high of 15.97 maf (147 percent of average) in water year 2011. In water year 2018 unregulated inflow volume to Lake Powell was 4.6 maf (43 percent of average), the third driest year on record above 2002 and 1977. [1]

Current Status	Current Operations	Inflow Forecasts and Model Projections

Updates Upper Colorado Region Homepage Hydrodata dashboard for Lake Powell Lake Powell Snow Chart Lake Powell Inflow Forecast Lake Powell Elevation Projections Lake Powell Release Projections Glen Canyon Dam Operations USBR Weekly Water Reports Upper Colorado Region Weekly Hydrology Summary Reservoir inflows (forecast and observed) Reservoir releases SNOTEL Lower Colorado Water Supply Report Water use Lower Colorado River Water Accounting Colorado River Basin Tea-Cup Diagrams USBR Monthly/Annual Reports 24-Month Study Monthly Summaries Annual Operating Plans for Colorado River reservoirs Snow Pack Reports Upper Colorado River Basin Snow Water Tracking Upper Colorado Basin Conditions Map Bureau of Reclamation- Snow Pack Report SNOWTEL Report The snowtel report is a calculating report, and takes approximately 3 minutes to run. Select the report under "Public", listed as "Colorado River above Lake Powell" (116 snowtel sites). Data source is updated at least daily. U.S. Drought Monitor U.S. Drought Monitor Tree Flow Data Inflow Volumes to Lake Powell and Release Volumes from Glen Canyon Dam 10-year average inflow (2015-2024): 8.61 maf 10-year average release (2015-2024): 8.45 maf Water Year Natural Inflow (maf) Unregulated Inflow (maf) Release Volume (maf) 2024 11.875 07.981 07.48 2023 13.421 08.58 2022 09.85 06.084 07.000 2021 07.15 03.502 08.230 2020 09.89 05.847 08.230 2019 17.67 12.951 09.001 2018 8.63 04.612 09.000 2017 16.40 11.905 09.000 2016 13.44 09.616 09.000 2015 13.41 10.174 09.000 2014 13.98 10.381 07.480 2013 09.11 05.117 08.232 2012 08.50 04.908 09.466 2011 20.16 15.971 12.518 2010 12.32 08.426 08.235 2009 14.27 10.220 08.236 2008 16.21 12.086 08.978 2007 12.56 08.754 08.231 2006 12.61 08.626 08.228 2005 16.89 12.795 08.232 2004 09.59 05.913 08.231 2003 10.53 06.161 08.229 2002 05.93 02.643 08.230 2001 11.04 06.994 08.236 2000 10.56 06.936 09.381 1999 16.43 12.800 11.204 1998 16.97 13.520 13.510 1997 21.15 17.053 13.824 1996 14.07 10.402 11.522 1995 19.80 15.905 09.223 1994 10.64 06.794 08.289 1993 18.63 14.437 08.102 1992 11.10 07.352 08.002 1991 12.35 08.801 08.121 1990 09.00 05.311 08.140 1989 09.60 05.939 07.981 1988 11.68 07.989 08.144 1987 16.61 13.377 13.429 1986 22.36 18.546 16.848 1985 21.06 17.517 19.094 1984 24.18 20.846 20.499 1983 23.70 20.371 17.493 1982 16.67 12.771 08.304 1981 08.68 05.639 08.295 1980 17.27 13.682 10.907 1979 17.55 14.189 08.297 1978 14.85 11.059 08.354 1977 05.52 03.529 08.260 1976 11.21 08.431 08.482 1975 16.53 13.095 09.255 1974 12.96 09.970 08.266 1973 19.14 15.974 10.108 1972 12.44 09.329 09.311 1971 14.73 11.798 08.591 1970 15.06 11.992 08.692 1969 14.45 11.520 08.823 1968 13.34 10.319 08.334 1967 11.71 08.979 07.797 1966 11.06 08.689 07.854 1965 18.36 15.046 10.820 1964 10.38 07.492 02.413 https://usea.org/sites/default/files/event-/Final_Colorado_Overview.pdf http://www.lakepowell.org/page_two/what_s_new/what_s_new.html https://www.hcn.org/blogs/goat/is-lake-powell-really-shrinking Stream Flow Gages Lake Powell Water Level Graphs Glen Canyon Dam releases (SCADA) Glen Canyon Dam releases (HDB), SDI for total release = 1872 Water Holes Canyon above the mouth Colorado River at Lees Ferry Paria River near Kanab, UT Paria River at Lees Ferry, AZ Badger Creek below highway 89A near Vermillion Cliffs, AZ Tanner Wash below highway 89A near Bitter Springs, AZ House Rock Wash above Emmett Wash near Cliff Dwellers, AZ North Canyon near Cliff Dwellers, AZ Shinumo Wash in Twentynine Mile Canyon near Cedar Ridge, AZ Colorado River near river mile 30 Colorado River above Little Colorado River near Desert View, AZ Moenkopi Wash at Moenkopi, AZ Moenkopi Wash near Cameron, AZ Little Colorado River at Grand Falls, AZ Little Colorado River near Cameron, AZ Little Colorado River above the mouth near Desert View, AZ Colorado River near Grand Canyon, AZ Bright Angel Creek near Grand Canyon, AZ Shinumo Creek Kanab Creek above the mouth near Supai, AZ Havasu Creek above the mouth near Supai, AZ Colorado River above National Canyon near Supai, AZ Colorado River above Diamond Creek near Peach Springs, AZ Lake Mead Water Level Graphs Projects Presentations and Papers 2025 Colorado River Basin Reservoir Storage: where do we stand? 2024 Basin Hydrology and Operations Basin Hydrology and Operations Basin Hydrology and Operations Basin Hydrology and Operations Upper Colorado River Basin IRA Drought Mitigation Programs Basin Hydrology and Operations Reservoir Storage at the End of 2023 – Holding On to What We Have 2023 Basin Hydrology, Operations and Water Quality Basin Hydrology and Operations Basin Hydrology, Operations, and Water Quality Basin Hydrology and Operations Glen Canyon Dam Operations and Upper Basin Hydrology and Water Quality Basin Hydrology and Water Quality 2022 Evaluating the Accuracy of Reclamation’s 24-Month Study Lake Powell Projections Basin Hydrology, Operations and Water Quality AMP Role Relative to Implementing the Drought Response Operating Agreement Basin Hydrology, Operations and Water Quality Basin Hydrology, Operations and Water Quality Basin Hydrology and Operations Basin Hydrology, Operations, and Water Quality Basin Hydrology, Operations and Water Quality Basin Hydrology, Water Quality, and Operations 2021 Colorado River Basin August 2021 5-year Projected Future Conditions Long-Term Hydrologic Projections for the Colorado River Basin and Methods for Considering Uncertainty Colorado River Basin April 2021 5-year Projected Future Conditions Basin Hydrology and Operations Basin Hydrology and Operations Update on Hydrology, Operations and Water Quality Conditions Basin Hydrology and Operations Basin Hydrology and Operations 2020 TWG Basin Hydrology and Operations Basin Hydrology, Reservoir Operations 2020 and 2021 Hydrograph Hydrology, Operations and Reservoir Release presentation Hydrology, Operations and Reservoir Release presentation Hydrology, Operations and Reservoir Release 2019 Basin Hydrology, Reservoir Operations and 2020 Hydrograph Presentation 2018 Basin Hydrology, Water Years 2018-2019 Operations PPT Basin Hydrology, Reservoir Operations 2018 and 2019 Hydrograph How Will the Colorado Run? The Colorado River in a Warmer World Basin Hydrology, Water Years 2018-2019 Operations PPT Basin Hydrology, Reservoir Operations 2018 and 2019 Hydrograph PPT The 21st Century Colorado River Hot Drought and Implications for the Future PPT Basin Hydrology, Water Years 2018-2019 Operations PPT Basin Hydrology, Water Years 2018-2019 Operations PPT Basin Hydrology, Operations and 2018 Hydrograph PPT Basin Hydrology, Water Years 2018-2019 Operations PPT 2017 Basin Hydrology and Operations February 2017 Glen Canyon Montly Operational Coordination Call Basin Hydrology, and 2017-2018 Operations Analysis of Water Losses and Impacts to the Grand Canyon Ecosystem of the "Fill Mead First" Proposal and PPT Basin Hydrology, Operations and 2018 Hydrograph 2016 Fill Mead First – A Technical Assessment Basin Hydrology and Water Year (WY) 2017 Hydrograph Basin Hydrology, Operations, and 2017 Hydrograph TWG: Basin Hydrology, Operations, and 2017 Hydrograph Basin Hydrology, Operations, and 2017 Hydrograph Glen Canyon Dam Operations During Equalization Project 2: Streamflow, Water Quality, Sediment Transport, and Sand Budgets in the Colorado River Ecosystem 2015 California Drought Monitor Lake Mead Issues and Lower Basin Shortage Preparedness Lake Mead Issues and Lower Basin Shortage Preparedness - Presentation Basin Hydrology Operations, and 2016 Hydrograph Basin Hydrology Operations, and 2016 Hydrograph 2016 Annual Operating Plan Basin Hydrology and WY 2016 Hydrograph Hydrology Update and 2016 Hydrograph Water Quality in Lake Mead and Upstream Influences: Dissolved Oxygen during 2014 Basin Hydrology, Operations, and 2016 Hydrograph 2014 Basin Hydrology, Operations, and 2015 Hydrograph Basin Hydrology, Operations Basin Hydrology, Operations, and 2015 Hydrograph and AIF: Development of Water Year 2015 Hydrograph Basin Hydrology, Operations, and 2015 Hydrograph 2013 Basin Hydrology and Operations Colorado River Basin Hydrology and Projected Glen Canyon Dam Operations DOI/DOE FY14 Hydrograph Approved FY14 Hydrograph Basin Hydrology and Operations Colorado River Basin Water Supply and Demand Study Executive Summary--Pre-Production Copy of the Colorado River Basin Water Supply and Demand Study Colorado River Basin Water Study & Demand Study - Final Study Reports 2012 Basin Hydrology Basin Hydrology and Operations Flow Temp Turbidity 2011 Basin Hydrology Basin Hydrology Secure Water Act Section 9503 (c) - Water and Climate Change Bureau of Reclamation Updates 2010 Basin Hydrology and Operations Basin Hydrology and PPT 2009 Basin Hydrology PPT Basin Hydrology and PPT 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. Other Stuff