April 2023 Colorado Water Supply Outlook Report and News Bulletin

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USDA Natural Resources Conservation Service

Colorado Water Supply Outlook -  April 7th, 2023

March Brought Record Snowpack Accumulation to Many Colorado Basins

Denver, CO – April 7th, 2023 – The basins of Western Colorado continued to benefit from a series of storms throughout the month of March. During this time 34 SNOTEL sites in the state received the highest or second highest March snowpack accumulation amounts on record. NRCS Hydrologist Karl Wetlaufer notes “The record high monthly snowpack accumulation fell on top of an already plentiful snowpack at many sites. This brought about 25 percent of SNOTEL sites in the state to their record or second highest values for April 1st.” The spatial pattern of snowpack accumulation and streamflow forecasts this winter has been a shift from the previous three years where Western Colorado has experienced well below normal snowmelt runoff volumes and basins that flow east observed more plentiful runoff. “This year should provide a welcome reprieve for water supply and depleted reservoir storage across Western Colorado after several years of low streamflow” Wetlaufer continued. While forecasts are for the most plentiful volumes in the western half of the state the average of forecasts in the Arkansas and South Platte are for near normal volumes, albeit with a lot of variability point to point.

Forecasted 50% exceedance volumes for the state of Colorado.

Reservoir storage across most major basins is near to slightly below normal except for the Gunnison and the combined San Miguel-Dolores-Animas-San Juan River basins of Southwest Colorado which are currently at 71 and 69 percent of normal, respectively. While several years of low streamflow have contributed to these deficits, current streamflow forecasts indicate that those values will likely be rapidly rising over the coming months. Given the plentiful snowpack and streamflow forecasts, in many areas reservoir management plans will also likely be taking flood prevention into consideration over the coming months as well.

 After three years of below normal streamflow runoff across the state, 2023 is bringing a welcome change from a water supply standpoint to most major basins of Colorado, and arguably to some that needed it most. Hydrologist Wetlaufer notes “Overall, the water supply outlook for Colorado is looking quite positive for the upcoming runoff season.” While plentiful water is certainly good news in many respects, and it is worth keeping in mind that it can also come with an increased flood risk and a friendly reminder that one wet year doesn’t immediately cancel out several dry years.” Wetlaufer summarizes “With forecasts far above normal streamflow in much of the state residents should also be mindful of increased flood risk during peak flow. Additionally, it is important to bear in mind that in some basins, with the Colorado River being the prime example, one year of plentiful streamflow will not be enough to solve bigger picture water supply challenges in the long run.”

Basin % Median Snowpack Last Year's % median Snowpack % Median Reservoir Storage Last Year's % Median Res. Storage
Gunnison 156 100 71 63
Colorado Headwaters 131 94 99 83
South Platte 111 92 94 105
Laramie-North Platte 131 91 --- ---
Yampa-White-Little Snake 149 84 90 80
Arkansas 103 98 90 91
Upper Rio Grande 140 101 104 93
SMDASJ* 177 92 69 65
Statewide 137 94 88 83

* combined San Miguel-Dolores-Animas-San Juan River basin

For more details see the April 1st Water Supply Outlook Report.

Colorado Snow Survey

Natural Resources Conservation Service
Colorado State Office
Denver Federal Center
Bldg. 56 Room 2604
PO Box 25426
Denver, CO 80225-0426

Phone:  (720) 544-2852
Email: co-nrcs-snow@usda.gov

Snow Survey Supervisor

Brian Domonkos (720) 544-2852

Assistant Snow Survey Supervisor

Karl Wetlaufer (720) 544-2853