Spring rain may prevent fish die-off in fall
Fish that rely on the Rogue River may have gotten a reprieve after April rain and snow boosted water supplies.
Lost Creek Lake, a massive reservoir north of Shady Cove, increased to 72% full as of this week. Managers are cautiously optimistic they’ll have enough water to release downstream into the Rogue River to help fish this year.
A month ago, dry weather in January, February and March had water and fish managers talking on the phone weekly about potentially dire consequences, said Dan Van Dyke, a biologist with the Oregon Department of Fish and Wildlife.
“Those calls were very depressing in late March and early April,” he said.
Chinook salmon that migrate from the ocean up the Rogue River to spawn in the fall could have faced low water, hot temperatures and disease outbreaks, leading to significant losses of fish as water supplies dwindled, Van Dyke said.
There now may be enough stored reservoir water, natural river flows and snow in the mountains to keep cool water flowing for spring chinook salmon that are migrating up the river now, fall chinook salmon and juvenile steelhead that grow in the summer, Van Dyke said.
Still, ODFW and the U.S. Army Corps of Engineers, which manages Lost Creek Lake and the William L. Jess Dam that impounds its waters, are dealing with a multi-year drought.
“We are pursuing a cautious approach to the drought that we’re in,” said Erik Petersen, U.S. Army Corps of Engineers operations project manager for the Rogue Basin and Willamette Valley Projects.
The Corps had to release water from Lost Creek Lake last summer and fall to help fish migrate and stay alive in the Rogue River.
Over the winter, the Corps released minimal amounts of water from the reservoir in order to conserve supplies for 2022, Petersen said.
The Corps hopes to end this summer with more water in the lake than it had at the end of the summer in 2021, he said.
Temperatures and water conditions this summer will dictate how much water the Corps releases for fish, managers said.
Lost Creek Lake formed in the 1970s after the construction of the William L. Jess Dam. The reservoir was built primarily to control destructive floods that once raged down the Rogue River.
The reservoir is doing that job, preventing an average of $1 million in flood damage annually, Petersen said.
The Corps has to keep some storage space available in both Lost Creek Lake and Applegate Lake south of Jacksonville to catch flood water. That blocks managers from filling them to the brim to boost water supplies.
However, the Corps is using improved forecasting capabilities and science to better predict flood risk. That means the reservoirs could be used to store more water, said Salina Hart, chief of reservoir regulation and water quality for the Corps’ Portland District.
Recently the Corps allowed Applegate Lake to fill higher than would normally be allowed for that time of year, managers said.
With climate change models predicting more precipitation will fall as rain rather than snow in Southern Oregon, and snow will melt off sooner, the area will have fewer natural reserves of water stored as snow.
That could increase the public’s desire for Lost Creek Lake and Applegate Lake to store more water.
However, climate change models also predict more extreme weather events, including flooding. Filling the reservoirs higher for water storage would mean taking on more flood risk, managers said.
Applegate Lake is currently 58% full, according to the Corps.
Lost Creek Lake and Applegate Lake are also used for recreation by boaters and people who like to fish, but flood mitigation, fisheries enhancement and irrigation are higher priorities, the Corps said.
It’s too early to tell how long jet boat companies will be able to ply the waters of the Rogue River this year, the Corps said.
Their seasons have been cut short some years due to low water.
The lakes managed by the Corps are different than a set of reservoirs managed by the U.S. Bureau of Reclamation primarily for irrigation.
This week, Emigrant Lake was 19% full, Hyatt Lake was 20% full, Howard Prairie Lake was 15% full, Fish Lake was 42% full, Fourmile Lake was 24% full and Agate Lake was 100% full.
Local irrigation districts are using spring rain to delay the start of the irrigation season as long as possible to conserve water in reservoirs depleted by years of drought. The irrigation season that normally runs from April into early October might last only one month, ending well before crops such as wine grapes and pears are ready for harvest.
Reach Mail Tribune reporter Vickie Aldous at 541-776-4486 or firstname.lastname@example.org. Follow her on Twitter @VickieAldous.