Despite two months of above-normal precipitation, the U.S. Army Corps of Engineers will continue drought conservation measures in the Missouri River Basin, a local official said.
Reservoirs are still feeling the impact of last year’s drought, noted Dave Becker, the Gavins Point operations project manager near Yankton.
Much of eastern South Dakota received 2 to 3 inches of rain earlier this month, with Yankton setting a one-day record of 3.16 inches for the October date. However, the basin was still recovering this year from exceptional drought in areas such as southeast South Dakota and northeast Nebraska.
“Because 2012 was such a dry year, the reservoirs used up a lot of stored water to meet the system’s needs. We were about 8 million acre feet of water short after last year in this reservoir system,” Becker said.
“This year is a normal year, and still the system as a whole is 7 million acre feet of water short. The Corps is continuing its drought conservation measures this winter.”
Dry soil conditions have resulted in near normal runoff during the current period, according to the Corps’ district office in Omaha.
Runoff in the Missouri River Basin above Sioux City during September was slightly below normal (91 percent of normal). The calendar year runoff forecast also remains below normal at 23.2 million acre feet (maf), 92 percent of normal.
The Missouri River will feel the impact of the drought conservation measures in the coming weeks, Becker said.
“One of the big effects will be releases that are lower this winter,” he said. “The releases will be more in the 12,000 cfs (cubic feet per second) range as opposed to the normal 17,000 cfs.
“The navigation season ends just a little bit before Thanksgiving, so then the flow will really be ramped down to that 12,000 cfs.”
The condition of the reservoirs will also affect hydroelectic production, Becker noted.
“For hydropower, water is our fuel for the power plant. As the water goes, the power generation goes,” he said. “It’s still pretty much a normal year at Gavins Point (for hydropower).”
The Corps also continues to make repairs to impacted communities throughout the basin two years after the historic flood of 2011, according to a news release from the Omaha District office.
The Corps sustained releases of 160,000 cfs at Gavins Point Dam and 157,000 cfs at Fort Randall Dam near Pickstown for several months during 2011.
The Corps will make repairs to spillway gates, outlet works, scour areas, work recreational facilities, roads and other flood control structures at each of our mainstem dam projects.
At Fort Randall Dam, several contracts were awarded in 2012 to repair damages. They include repair of gates and project roads.
Three of the contracts have been completed. They include road repairs, toe drain repairs and spillway gallery repairs. The gate repair contract is on-site and has begun repairs. The gate repairs are scheduled for completion in summer 2015. All other repairs are scheduled for completion in early 2014.
At Gavins Point Dam, seven contracts were awarded in 2012 to repair damages. They include repair of gates, tailrace erosion protection, relief wells and horizontal outfalls, and spillway slab.
Three contracts have been completed. They include repairs on toe drains, tailrace erosion protection and boat ramp repairs.
The gate repair is on hold, pending design revisions. Relief well installation and spillway slab repair are both under way. Gate repairs are scheduled for completion in fall 2014. All other repairs are scheduled for completion this fall.
In addition, 10 contracts were awarded in 2012 to repair damages along the Missouri River. They include repair of bank stabilization and navigation structures and other infrastructure. Contractors continue working on the river.
The bank stabilization repairs to the navigation reach between Sioux City and Rulo, Mo., are scheduled for completion in summer 2015. All other repairs are scheduled for completion this fall.