News Release
Oct. 14, 2011 Update  From MSAC Reports


● Photo Above: The Loafin' Shed at Monfore Park
Receding water uncovered a sand pile inside "The Loafin' Shed" at Monfore Park, a private getaway about nine miles upstream of Niobrara, Nebraska, on the Missouri River (South Dakota side). High, prolonged flows carved a new river landscape. (Photo by Mary Hurd/MSAC Photo)

Researchers size up results of heavy Missouri flows
As people along the Missouri River pick up the pieces after this summer’s flooding, the receding waters are uncovering a different river and landscape.

One vivid example is at Monfore Park, a private park about nine miles upstream of Niobrara, Nebraska on the South Dakota side of the Missouri River. Picnic shelters, a bathhouse, electrical hook-ups, a dock and boat ramp welcomed friends and family of Rick and Mary Hurd, who live nearby. This summer several feet of water inundated the park, agricultural fields and dozens of homes to the south at Nebraska’s Lazy River Acres. Today, the river has receded and last summer’s flowing, green landscape at the park has been replaced with a sandy, lunar-like scene.

“Before the flood, the park was all grass. It took me over two hours every week or two to mow it, even with a big diesel mower. The field at right was lush, green alfalfa. There were at least four campers at hookups all summer, and most weekends the park was filled with friends,” Mary Hurd said. “It was not unusual to have three dozen or more people camping, boating, and enjoying the river at Monfore Park.”

The floods of 2011 not only turned lives and recreation upside down for hundreds of people up and down the river, but also showed its force with the land. Unprecedented flows for many weeks have moved sediment from beds, banks and tributaries to other locations in the reservoirs. Data detailing bank erosion, scouring or sediment movement is not yet available, but it is in the works. Sediment movement and channel erosion throughout the summer has been monitored by the United States Geological Survey and will be studied further by the United States Army Corps of Engineers and other federal agencies.

Hearing news of river depths growing dozens of feet in places and sandbars gone and new ones appearing is not uncommon.

“We have to keep the focus on what is under the water as well as what is on top,” said Howard Paul, technical coordinator for the Missouri Sedimentation Action Coalition.

As part of flood rehabilitation efforts, the Corps of Engineers is gathering river information including surveying  all the sediment rangelines from Sioux City to Fort Randall Dam, additional sections at the face of the Lewis and Clark Lake delta along with Niobrara River rangelines up to the Highway 12 Bridge. This data is expected to be delivered by late spring 2012, according to Paul M. Boyd, hydraulic engineer at the Corps’ Omaha District.

Surveying the bottom of the reservoir gives managers information on the water-storage capacity.

Other information to be collected includes Fort Peck degradation ranges down to the Garrison Reservoir headwaters and the lower Yellowstone River. Imagery data also will be collected on the lower Yellowstone, between Garrison Dam and Lake Oahe, and from Fort Randall dam to Rulo, Nebraska. Expected data delivery is late spring of 2012, dependent on when weather allows for collection.

“We expect with updated data we will revisit the Fort Randall and Gavins Point degradation reports as well as update changes in capacity to Gavins Point Dam,” Boyd wrote in an email to MSAC.

The summer of 2011 marked the wettest season and year that the Missouri River basin has experienced since detailed record keeping began in 1898. May, June and July brought three consecutive months of record runoff above Sioux City. June was the highest runoff month on record with 13.8 million acre feet.  The previous monthly runoff record was 13.2 million acre feet in April of 1952. May runoff totaled 10.5 million acre feet (the third highest month) and July recorded 10 million acre feet (the fifth highest month).  Runoff for the calendar year is expected to reach 60.4 million acre feet, 244 percent of normal, according to the USACE. The previous record of 49 million acre feet was reached in 1997.

Water storage peaked in the Missouri River reservoirs on July 1 with 72.8 million acre feet. July closed at 69.6 million acre feet. The previous storage record was 72.1 million acre feet in 1975.

MSAC participated in a meeting Oct. 4 with various agencies in Charles Mix County along with Col. Robert Ruch, Commander of the Corp’s Omaha District. Ruch indicated that with perfect foresight an additional 8.6 million-acre-feet of storage may have held the flood with 70,000 to 100,000 cubic feet per second flows. That would have meant water levels at the Garrison and Oahe reservoirs to be about 12 feet lower to account for the additional storage space. Turning the reservoirs into “big bathtubs” and creating drought-like conditions does not meet management objectives, he said.

In September, the Corps hired an independent review panel to review, analyze and assess their operation of the six main stem dams along the Missouri River leading up to, and during the flood of 2011. Hydrologists with the National Weather Service, U.S. Geological Survey, Natural Resources Conservation Service and a Colorado State University professor make up the panel.

Water management in the system will be discussed for months to come. The floods of 2011 undisputedly, funneled more sediment-moving power in the Missouri River than has been experienced since the system’s closure. This power was not only great, but also long-lasting. 

The transporting power is proportional to three core things: the product of the river’s discharge rate, the water slope down the channel and the duration of the discharge, according to Ron Zelt, associate director of the U.S. Geological Survey’s Nebraska Water Science Center in Lincoln.

“Neglecting the increase in energy due to slope to simplify the discussion, in 2011 we observed ‘much above normal’ squared. Indeed, as the flood waters recede, we see much evidence of the river’s power in damage to roads and other structures, deep scour holes even after most were partly refilled by sediment as the flood waned, and numerous changes to sand bars, islands, and river banks, especially wherever they were unprotected by revetments,” Zelt said.

The Corps estimates the average, annual sediment load accumulating in the reservoirs to be 89,700 acre feet. Since its creation, the Missouri River reservoir system has lost more than 5 million acre feet of storage due to accumulating sediment based on pre-2011 flood surveys. Expectations are that the storage lost will be in excess of 5 million acre feet, which updated surveys may confirm. Even though that 5 million acre feet goes more than half way to meet what was needed to possibly quell the floods, Corps officials maintain that storage lost to sediment does not change the level of what is reserved each season for flood control.

MSAC stresses the importance of maintaining storage capacities for water so Americans can realize the reservoir’s benefits for future generations. Slowly losing storage capacity diminishes the ability to hold water for flood control, recreation, drinking water, hydropower generation, and even navigation.

“Every acre foot of water storage is important. Storing water rather than sediment makes more sense. Gradually losing this ability in the reservoirs is not a resource conscious way for us to manage the system. The build-up of sediment not only is a problem for the people of Niobrara, Springfield, Bismarck, Mandan or Pierre, Fort Pierre, it’s a concern for everyone living near the 2,000 –plus miles of Missouri River along with people hundreds of miles away drinking water from the river or using electricity generated with the river’s energy,” said Sandy Korkow, MSAC executive director.  

Howard Paul describes the lost storage to be equivalent to a lake one hundred miles long, ten miles wide, with an average depth of more than seven feet. The runoff of 2011 still would have created problems even if all original storage capacity was available for water, he said.

Accumulated sediment contributed to flooding in 2011 by creating a damming effect within the reservoirs in places like the area of Fort Pierre, South Dakota and indirectly in Niobrara, Nebraska. Inflowing water has to flow over the sediment “dams” which then raises the surface elevation of the river. This also raises the ground water table in the soils next to the river.

“As this sediment build up continues, the effects continue to multiply,” Howard Paul said.

Half the storage capacity of Lewis and Clark Lake, the smallest Missouri River reservoir, is expected to be full with sediment by the year 2045. Based on 2007 surveys Lewis and Clark Lake has experienced a storage loss of 22 percent, according to the Corps. This storage loss results in less than a .1% reduction in total system flood storage. Even though it may appear sediment has left certain areas it has merely moved to another spot in the reservoir.

“What the flood of 2011 meant for the reservoirs, where almost all of the incoming sediment becomes deposited, is an accelerated loss of water-storage volume as it became occupied with sediment deposits. Federal scientists were busy during the flood making measurements of the sediment transport rate at selected points along the river. Once their analyses are complete, we should have a general idea of how much sediment may have entered some main-stem reservoirs. A cross check on those estimates eventually will be provided when the Army Corps of Engineers surveys the bottom of each reservoir to estimate its remaining water-storage capacity,” Zelt said.

MSAC supporters know the Missouri River is a complicated system to manage. Most of the reservoirs’ purposes require the use of stored water, whereas ensuring the greatest ability to provide for flood control means less water in the reservoirs. Court orders directing the fostering of threatened and endangered species add another consideration to the mix. Limited funding creates winners and losers and even stalls some programs such as the evaluation of the Flood Control Act of 1944 and its application to today.

The larger reservoirs will take hundreds of years to fill with sediment, however, MSAC points out that the harmful effects of sedimentation are already being felt and that a new way of managing sediment needs to be put into effect that will enable the system to continue to fulfill the authorized purposes without a reduction in benefits. 

“We know there is not one single action that will address problems created by accumulating sediment. It will take cooperation of several agencies, land managers, and the public to maximize the system’s potential,” Korkow said. “We are encouraged that after this dark summer we can move forward with better knowledge for the future.”

The public is encouraged to participate in the Corps’ Annual Operating Plan meetings coming up in October and November at eight locations: Oct. 24/Omaha, Nebraska; Oct. 25/St. Joseph, Missouri; Oct. 26/Overland Park, Kansas; Oct. 27/Jefferson City, Missouri; Oct. 31/Glasgow, Montana; Nov. 1/Bismarck, North Dakota; Nov. 2/Pierre, South Dakota; and Nov. 3/Sioux City, Iowa. Meetings will consist of an afternoon open house, an evening public meeting with a Corps’ presentation followed by a question and answer session. The Annual Operating Plan details information regarding water management in the Missouri River Mainstem Reservoir System through December 2012.

To view the 62-page draft of the Corps’ Annual Operating Plan visit this link:  http://www.nwd-mr.usace.army.mil/rcc/reports/pdfs/draft2011-2012AOP.pdf

Above: River power ate away at the natural banks and the area around the protective concrete near the Oahe Dam's stilling basin. (Photo by Scott Carbonneau/City of Pierre)

For more photos and news follow this link to a PDF of the entire newsletter.

Would you like to receive a copy of the newsletter? Consider joining MSAC and support efforts to educate the public about the problems of sedimentation. Learn more here.

 ▪ News Briefs
Keep up to date with MSAC online
The Missouri Sedimentation Action Coalition maintains a web site at www.msaconline.com. General background on the problems associated with accumulating sediment is posted there along with newsletters, press releases and membership information.

In October, MSAC launched a presence on Facebook in efforts to reach more people and keep up with the rapid release of news.

MSAC unveils display at South Dakota State Fair
Fairgoers saw the problems associated with sediment up close with a full-color display hosted by MSAC in Huron, Sept. 1-5.

In addition to the display where people could pick up information to take with them, MSAC presented educational videos three times daily. MSAC distributed several dozen free copies of the video narrated by Tony Dean and communicated with several hundred people at the booth.

The display will travel to several communities in the upcoming months. If you are interested in bringing the display to your community, contact Sandy Korkow with MSAC at 605-369-2745 or sandrak@gwtc.net.

Howard Paul, technical coordinator email: hpaul@sio.midco.net
1511 Holiday Drive
Canton, SD 57013 (605)987-4165 (605)770-0998