Water officials: Plan for the ‘worst-case scenario’

Steamboat Pilot, September 23, 2022

Panelists speaking to a large group of water professionals and community members gathered for the 2022 Yampa Basin Rendezvous in Steamboat Springs this week say water managers must think and plan for the “worst-case scenario.”

In other words, after years of drought conditions in Colorado, any lingering optimism for a return to previous patterns of rain showers most afternoons in the High Country is not a realistic outlook. Water managers now need to use the most conservative, lower water flow predictions to manage shrinking water resources effectively, said Andy Rossi, general manager of the Upper Yampa Water Conservancy District.

“As a reservoir manager, we have to look at worst case scenario. We plan for 2012 and hope for 2011,” Rossi said as part of opening panel on Thursday, Sept. 22, at Colorado Mountain College. “Forecasts tend to lean to the optimistic side, but (through) the test of time, optimism is not valid. In a basin with little storage, we definitely pay attention to the worst-case scenario.”

The annual volume of water in the Yampa River Basin was 1.5 million-acre-feet in the early 1900s but now is 1.12 million-acre-feet, Rossi noted.

Rossi compared the two consecutive years from 2011 and 2012 as one example of water projection difficulties. During the wetter 2011 at the Fifth Street river gauging station in downtown Steamboat, the flow on June 7 was 4,780 cubic feet per second compared to 305 CFS on the same date in 2012.

Last week, at the same gauging station, the natural river flow contributed only half of the flow because approximately 50% of the flow was from storage releases from Stagecoach Reservoir, he said.

“I think people do not have any concept of what the river would have looked like had releases not been made from Stagecoach under the Colorado Water Trust contract,” explained local Water Division 6 Engineer Erin Light.

Despite rain in Routt County this week, 83.4% of Colorado currently is rated “abnormally dry,” according to the National Integrated Drought Information System found at Drought.gov. NIDIS reports 47.8% of Colorado is in “moderate drought,” 17.5% is in “severe drought” and 3.9% in “extreme drought.”

Although precipitation levels in the Yampa River Basin historically include highly variable ups and downs, data shows an “incredibly sharp recent decrease in precipitation” that led to five of the lowest water inflows into Stagecoach Reservoir during the past 10 years, Rossi said. From 2010 to 2021, the annual precipitation in Routt County dropped by 5.26 inches, he said.

Another concern surrounding low water flow is the degradation of water quality.

The topic for this year’s fifth annual Yampa Basin Rendezvous was “Enhanced Observations for Water Resilience in the Yampa River Basin.” Rossi said planning for that resilience requires understanding the vast variability of precipitation throughout the basin of the 250-mile Yampa River. The Yampa River Basin water originates in the Flat Tops Wilderness Area and later doubles in volume by adjoining water from Elk River coming from the Mount Zirkel Wilderness Area, which is one of the wettest places in Colorado outside of Wolf Creek Pass.

The Yampa River extends from above Stillwater Reservoir at 10,259 feet in Garfield County and flows downstream to about 4,700 feet to one of the driest areas of Colorado at Echo Park in Dinosaur National Monument. There, the Yampa meets the Green River, where annual precipitation is less than 10 inches, and the Green River flows to the imperiled Colorado River.

Compared to other river basins in Colorado, the combined water storage capacity for the six major reservoirs in the Yampa River Basin is low at 104,220 acre-feet, Rossi said, pointing out that represents 40% of Lake Dillon storage capacity in Summit County with 257,304 acre-feet.

Panelist Chuck Collum, executive director of the Upper Colorado River Commission, told the audience that warming climate conditions are changing the times of the peak river flows that is key to the amount of water runoff each year. The month of April is key to runoff efficiency, as cool and wet weather in April is best for river flows.

“Snow pack matters, timing of runoff matters, and temperatures matter,” Collum said.

For example, early peak snowfall in February and melt in March and April 2012 produced more water runoff. However, in 2018 with less snow, the water runoff was almost the same because the peak snowfall came later in March and April and runoff hit in May.

Panelist Kelly Romero-Heaney, assistant director for water policy for the Colorado Department of Natural Resources, said groups at science-based conferences such as the rendezvous are key to developing nuggets of scientific advice to pass along to state legislators.

“It’s hard for them to have bandwidth to take technical data and distill it into policy,” she said.

Community members were urged to learn more about local water issues and to review the final version of the Yampa Integrated Water Management Plan that was released earlier this month available online at the Yampa-White-Green Basin Roundtable website at YampaWhiteGreen.com.

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Steamboat Pilot & Today
Suzie Romig
Original Article