News Release
| Release Number: | 06-003 |
| Dated: | 1/31/2006 |
| Contact: | Paul T Johnston, 402-697-2552 |
OMAHA – The Army Corps of Engineers today released the 2006 Final Annual Operating Plan for the Missouri River. It describes how the large dams and reservoirs on the Missouri will be operated this year for a wide variety of runoff conditions.
The annual operating plan includes two “spring pulses” to comply with the requirements of the Amended 2003 Biological Opinion published by the U.S. Fish and Wildlife Service, provided there is sufficient water in the main stem reservoirs. To conserve water during the current drought, the pulses will be delayed until 2007 if there is not at least 36.5 million acre feet (MAF) of water stored in the reservoir system on March 1 and on May 1, 2006. With normal runoff conditions, the current forecast for storage on March 1 is 36.6 MAF.
The opinion identified pulses in the spring from Gavins Point Dam as part of the Reasonable and Prudent Alternative to avoid jeopardizing the continued existence of the pallid sturgeon. The 2-day pulses are intended to mimic the historic ebb and flow of the river to benefit the spawning of the endangered pallid sturgeon.
“The Corps and Service closely coordinated on the plan for the pulses. We acknowledge and greatly appreciate the intense interest and hard work over the past year by the 50-member Missouri River Plenary Group comprised of Tribal representatives and regional stakeholders,” said Brig. Gen. Gregg Martin, Northwestern Division Engineer. “It included representatives from the full range of basin interests. The Corps used the input from the group to develop a plan that we believe complies with the Endangered Species Act, meets the congressionally authorized purposes for the dams and reservoirs and allows the Corps to fulfill its trust and treaty responsibilities.”
The pulses are much smaller in size and duration than in previous plans and greatly reduce the risk to river and reservoir users alike. The Corps is developing a comprehensive monitoring and evaluation program to measure the sturgeon’s biological response, affects on historical/cultural and burial sites, water intakes, interior drainage and any other potential negative impacts that may result during the pulses. These results will be used to refine the timing, duration and size of future pulses.
The 2006 plan maintains the “flow limits” currently in the Master Water Control Manual. These are the river levels that act as triggers for reducing releases from the reservoirs during high downstream flows.
The March pulse will correspond to the annual increases in releases that support the opening of the navigation season on April 1. Its magnitude is no higher than what would be experienced if full service flows were provided, as occurs during normal runoff conditions. Therefore, no unusual impacts are expected in either the downstream or upstream areas.
Given current storage and runoff predictions, the magnitude of the May pulse will be approximately 10,000 cfs. River levels downstream of Gavins Point are expected to rise about 3 feet in the Omaha reach and about 1.5 feet in the Boonville, Mo., reach during the 2-day peak. The pulse will be initiated between May 1 to 19, based on water temperature below Gavins Point and the status of nesting terns and plovers below Gavins Point and Fort Randall.
Water may be staged in Fort Randall reservoir early in the spring to reduce the negative impacts of the May pulse to storage in the three largest reservoirs of Oahe, Garrison and Fort Peck. This would result in a 2-foot decline in Fort Randall immediately following the pulse. By the end of the year, the storage will be balanced. The impact of both pulses will be 0.1 to 0.3 feet in each of the three upper reservoirs.
The Missouri River Master Manual does not contain the technical criteria for the spring pulses. A revision to the manual will include the criteria and is expected to be completed by the end of February.
The annual operating plan also describes the overall management plan for the dams and reservoirs. It anticipates that there will be only minimum flows for the 2006 navigation season, which could be shortened by 15 to 58 days, depending on runoff this winter and spring. A final determination on season length will be made on July 1, 2006.
Releases from Gavins Point may be cycled during May to encourage the least terns and piping plovers to nest high on the sandbars. They will be adjusted in June to meet navigation flows through mid-August when the birds begin their annual migration south.
Steady to rising reservoir levels during the spring fish spawn are likely if there is normal or above normal runoff. However, continued drought conditions may make that impossible at all three of the upper reservoirs. If rising pools cannot be provided at all three, releases from Garrison Dam will be adjusted to provide a steady to rising pool in that reservoir during April and May. The ability to provide rising pools during the forage fish spawn depends on the volume, time and distribution of the runoff from melting snow on the plains and in the mountains of Montana and Wyoming.
The 2006 Annual Operating Plan with a detailed description of the spring pulses is available on the Northwestern Division website: www.nwd.usace.army.mil and in hard copy by writing to: Water Management Division, U.S. Army Corps of Engineers, 12565 West Center Road, Omaha, NE 68144.