The Convincing Case Against Gavin’s Point Dam

GavinsPointDamGavin’s Point Dam lies athwart the Missouri River a few miles northwest of the town of Yankton, South Dakota.  Federal engineers built the dam in the 1950s as part of the Pick-Sloan Plan for Missouri River Development. The key architect of the Pick-Sloan Plan, Colonel (and later General) Lewis A. Pick, claimed that the plan’s dams and channelization works would provide residents of the Missouri Basin with increased wealth, enhanced social stability, and flood control.

Wealth would come in the form of a heavily-utilized barge channel from Sioux City, Iowa, to the river’s mouth near St. Louis, Missouri.  Barges navigating the Lower Missouri would decrease the transportation costs of valley agriculturalists and industrial manufacturers by carrying Midwestern products cheaper than land-bound railroads.  Any savings in transportation costs would be pocketed by valley residents, who could then spend their new-found wealth to improve the quality of their lives.

Pick asserted that the plan’s earthen dams in the Dakotas would forever end flooding along the Missouri main-stem south of Sioux City.  Valley residents would be secure in their property once the Missouri had been caged behind big dams.  Social stability would result from both increases in per capita income and from the end of economically-disruptive floods.  Pick believed the plan that he co-authored with Glenn Sloan of the Bureau of Reclamation would herald in a new era along the Mighty Missouri – one of peace and prosperity.  Needless to say, Pick placed great hope in the development of the Missouri River.

It has been almost seven decades since the congressional passage of the Pick-Sloan Plan and 56 years since the closure of Gavin’s Point Dam.  In the intervening years, the dammed, engineered, and manipulated Missouri has failed to deliver Pick’s promised benefits.

To any objective observer, the navigation channel constructed south of Sioux City has been an abject failure.  In 1951, Army officials testified during a congressional hearing that the Missouri navigation channel would carry 5 million tons of material by 1980.  The Army made this claim to justify the huge expense of constructing the nine-foot channel.  Contrary to the assertions of Army officials, the Missouri has never carried 5 million tons of cargo per year.  Barge traffic peaked on the river in the 1970s and then began a precipitous decline.  In 2008, barge operators carried a minuscule 175 tons on the Missouri.  That is less than two full rail cars.  In 2009, the amount of cargo on the river increased to 245,000 tons, which was still far below the cargo estimates the Army used to justify the barge channel’s construction costs.

What is surprising about the above statistics, besides how little traffic has actually emerged on the river, is that the Army continues to spend millions to maintain the navigation channel.  Recently, the Army requested $3,050,000 from Congress to ensure the riprapped Lower Missouri remains inside its rock-lined banks.  The question that begs to be answered is this: can the millions spent on maintenance of the navigation channel be justified on economic grounds?  Someone as bipartisan and esteemed as Senator Byron Dorgan of North Dakota believes that the Army’s management of the Missouri River system for navigation does not make any sense.

The Army has failed in other ways along the Missouri.  For example, after completion of the last Dakota dam in 1966, floods continued to strike the Lower Missouri.  The Missouri jumped its banks in 1971, 1973, 1984, 1993, 1995, and throughout the first decade of the 21st century.  Just this past summer, a Missouri River flood sank portions of central Missouri.  Despite the failure of the Pick-Sloan Plan to live up to expectations, the U.S. Army (which has never liked to admit defeat and which refers to a retreat as an “advance to the rear”) continues to operate its Missouri River dams and reservoirs in support of the navigation channel.  One of the primary purposes of the dams at Gavin’s Point, Fort Randall, Big Bend, Oahe, Garrison, and Fort Peck is to supply the water for a nine-foot channel in the river south of Sioux City.  Millions or dollars are spent each year on maintenance of the dams.  In 2009, the Army received $8.7 million to spend on maintenance work for Gavin’s Point and Fort Randall dams.  If the new deficit hawks in the GOP (they weren’t deficit hawks during the Bush years), such as John Boehner and Mitch McConnell, need a further example of a wasteful pork-barrel project, they need look no further than the Missouri River.  Congress could immediately save millions of taxpayer dollars by de-authorizing the navigation channel and halting its maintenance. Additionally, Congress could decommission and dismantle two Missouri River main-stem dams with negligible consequences for the flood situation along the lower river.

It is a historical fact that the Army built more dams and acquired more reservoir storage space than it needed to provide flood control to the Lower Missouri Valley.  In 1944, the Bureau of Reclamation concluded that approximately 40 million acre-feet (MAF) of reservoir storage would be sufficient to curtail the Missouri’s annual spring and summer rises.  Glenn Sloan, at the Reclamation Bureau, believed that large dams at Fort Randall, Big Bend, and Oahe (in conjunction with the already-completed Fort Peck Dam) would be adequate to protect the lower valley from devastating floods.  Sloan did not consider Gavin’s Point or Garrison necessary for flood control or support of the navigation channel.  Nevertheless, the Army constructed Gavin’s Point and Garrison dams.  The Army also continued to manage Fort Peck for the support of navigation south of Sioux City.  The Army built over 73 million acre feet of storage into the Missouri River reservoir system, which was nearly double the amount of storage Sloan believed necessary to control the river.  What Sloan’s 1944 calculations make clear is that Garrison and Gavin’s Point dams could be removed without affecting flood heights at Sioux City.  The four remaining dams at Fort Peck, Oahe, Big Bend, and Fort Randall will keep the lower valley safe from superfloods.

The least useful of the Missouri River dams is Gavin’s Point.  Its ineffectiveness is only exacerbated by the siltation of its reservoir. According to Paul Boyd at the Omaha District, U.S. Army Corps of Engineers, the reservoir behind Gavin’s Point Dam has lost between 22% and 24% of its capacity since the closure of the dam’s earthen embankment in 1955.  As the reservoir fills in, Gavin’s Point Dam and reservoir offers fewer benefits. For example, the reservoir has always been too small to appreciably reduce flood heights at Sioux City.  That reservoir is now even smaller.  Additionally, the recreational value of the reservoir diminishes each year as the silty delta at its headwaters advances southeastward toward the upstream face of the dam.  Water skiers, sail boaters, and house boating enthusiasts find the boggy wetlands at the head of the reservoir to be unsightly, difficult to navigate, and even harder to enjoy.

The Army initially wanted the lake behind Gavin’s Point Dam to act as a re-regulating reservoir, meaning it would smooth out the surges of water descending downstream from the larger Fort Randall Dam.  Once the turbulent waters exiting Fort Randall Dam had been calmed inside Gavin’s Point reservoir, the dam would release those waters into the navigation channel, where they would pose no threat to barges and tows. But with Lewis and Clark Lake now losing its storage capacity to siltation, its ability to smooth out water surges has been reduced.  Furthermore, with the navigation channel in a state of disuse, Gavin’s Point Dam has lost its main reason for existence – to support downstream navigation.  There is less and less of a justification for Gavin’s Point Dam.

Nonetheless, there is talk of extending the life of Gavin’s Point Dam by dredging its reservoir.  Predictably, Yankton area businesses favor this option.  Where the Army would put all the grimy sludge dredged out of the reservoir is anybody’s guess.  Dredging is a multi-million dollar proposition that offers only a short-term solution to a long-term issue.  The reservoir will continue to fill with silt regardless of any dredging operation.

Another scheme to save Lewis and Clark Lake involves diverting the Niobrara River (the main source of silt in the reservoir) around the dam by either constructing a large pipe or a canal along the western side of the reservoir.  This supposed solution is not cost-effective.  The recreational value of the reservoir does not justify the expense of redirecting the entire Niobrara River.  A third proposal entails “flushing” the reservoir of accumulating sediments.  This method may or may not work.

There is a fourth option available to decision-makers.  Instead of continuing to waste money to maintain the largely useless Gavin’s Point Dam, it should be decommissioned when the reservoir fills with silt.  The benefits of this option for the ecological health of the Lower Missouri would be readily quantifiable and far-reaching.  The water passing into the Missouri from the unregulated Niobrara would provide the Lower Missouri with a small but important pulse in the spring and early summer.  Such a pulse would act as a wake-up call for Missouri River fish species.  The pulse would signal fish to spawn, thus aiding fish propagation.  Also, the organic matter entering the lower river from the Niobrara would provide food for aquatic insects which would then feed fish.  Again, the Niobrara would help boost Missouri River fish numbers.  Niobrara River sediments would foster sandbar formation which would provide habitat to the endangered least tern and piping plover.  Plus, Niobrara River sands and gravels would increase the Missouri’s turbidity levels – which will aid fish dependent on turbidity for survival, such as the pallid sturgeon and paddlefish.  Such turbidity might curtail the explosive population growth of such sight-feeders as the invasive silver carp and bighead carp.

A decommissioned Gavin’s Point Dam would enable threatened and endangered fish species to once again move freely upstream to their ancient spawning grounds at the mouth of the Niobrara.  At present, the dam blocks the movement of paddlefish and pallid sturgeon to those spawning beds.  Decommissioning of the dam would enable that annual migration to once again take place, contributing to self-sustaining populations of those species.  Those reestablished migrations would put less pressure, and fewer costs, on fish hatcheries currently working to maintain those fish populations.  The larger fish populations that would result from the reintroduction of Niobrara silt and organic matter into the Lower Missouri would aid in the reestablishment of populations of predator species along the river – such as otters.  Recreational pursuits, including bird watching, fishing, and hunting would be enhanced along a more biologically-diverse Lower Missouri.

The strongest advocate for preserving Gavin’s Point Dam and reservoir is the Yankton Area Chamber of Commerce.  Local businesses want to continue to benefit from the four-month-long reservoir recreation season.  Such a narrow economic interest must be subsumed to the ecological health of the much larger Missouri River system.  All in all, the future decommissioning of Gavin’s Point Dam and reservoir will be a win for the public and for ecology.

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One Response to The Convincing Case Against Gavin’s Point Dam

  1. Susan Harris says:

    This article was written Feb 2011. i was wondering if the author had any more comments regarding Gavins Point since the devasting flooding began in May?

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