A Butiful Plain: The Oacoma Bottom, the Missouri River, and the Legacy of Lewis and Clark

[This article first appeared in the May 2019 issue of “We Proceeded On.”]

“…the first comers in a land can, by their individual efforts, do far more to channel out the course in which its history is to run than can those who come after them….”  Theodore Roosevelt, July 4, 1886, Dickinson, Dakota Territory.[1]

On the morning of Sunday, September 16, 1804, after having travelled a little over a mile upstream from the previous night’s camp, Meriwether Lewis and William Clark, and the men aboard the keelboat and two pirogues, landed on the west bank of the Missouri River at a place later known as the Oacoma Bottom (west of today’s Chamberlain, South Dakota).  The exploring party spent the next two days at this location, drying clothing and equipment, observing flora and fauna, and hunting bison and deer.  The men had such a wonderful time at this Missouri River bottom that they referred to it in the journals as “Pleasant Camp.”

Several expedition members described Pleasant Camp and its environs. Clark referred to the bottom as “a butifull Plain Surrounded with timber.”[2]  John Ordway wrote, “…we Camped on S.S. in a handsome bottom of thin timbered land, lately burned over by the natives, it had grown up again with Green Grass which looked beautiful.”[3]  But it was Lewis, who spent all of Monday, September 17, traipsing across the valley lowlands and the plains above, who penned the most memorable lines. “…this senery already rich pleasing and beautiful, was still farther heightened by immence herds of Buffaloe deer Elk and Antelopes which we saw in every direction feeding on the hills and plains.  I do not think I exaggerate when I estimate the number of Buffaloe which could be compreed at one view to amount to 3000.”[4]

The Oacoma Bottom and the lands around it held more than just bison, white-tailed deer, elk, and pronghorn.  The exploring party also saw wolves, coyotes, porcupines, rabbits, and what the men called “barking squirrels” or prairie dogs.  A large prairie dog town pockmarked the entire bottom, stretching three miles long and a mile wide.  Cottonwood, elm, ash, and oak grew in the midst of the prairie dog town; and a quarter mile to the rear of the explorer’s camp stood a grove of plums – now ripe with the season.

The super abundance of life witnessed at, or near, the Oacoma Bottom, on September 16 and 17, 1804, was no mere coincidence. Biological diversity was not evenly distributed along the Missouri or across its vast drainage basin.  Rather, flora and fauna concentrated in the valley’s “bottoms.”

Bottoms differed from bottomlands.  Bottomlands lay next to the river and were subject to annual inundation.  Bottoms, on the other hand, stood on top of the second or third terrace above the Missouri and were immune to most floods, which meant trees had time to take root and grow.  As a result, bottoms often contained healthy stands of timber.  Rich soils blanketed the bottoms – the result of the decomposition of organic matter, the defecating of mammals, and the infrequent deposition of Missouri River silt.  Such soils fostered the growth of herbs, grasses, wild fruit, and nut trees.[5]  Edible plants brought bison, white-tailed deer, elk, pronghorn, and all sorts of other creatures into the bottoms.  The big grazers in-turn attracted predators, such as grizzly bears, wolves, and coyotes.

The Oacoma Bottom was one of many that once existed along the Missouri from the Platte to the Three Forks.  For instance, a small bottom once occupied the flatland between the mouth of Perry Creek and the mouth of the Floyd River (the site of today’s Sioux City).  Another dominated the eastern edge of the Big Sioux River a mile above its mouth.  Others sprawled out along the Missouri just downstream from the James, Niobrara, and Cheyenne rivers – to name a few.  One of the Missouri’s grandest bottoms extended six miles along the west bank of the Missouri north of the Bad River confluence.[6]

The bottoms acted as oases in an otherwise harsh land.  When drought struck the northern plains, the bottoms, which still contained food and water, filled with mammals, birds, and burrowing creatures.  During cold, snowy winters, all kinds of animals found shelter from frigid temperatures and deadly winds in the bottoms, nestled amongst the trees or lying low in the high grass.  Because of their ecological role as refuges, the bottoms helped sustain biological diversity across the northern plains for thousands of years.

In 1804, the Lewis and Clark Expedition witnessed firsthand the biological diversity present in, and around, a single Missouri River bottom.  Had the expedition reached Oacoma in June (the wettest month on the northern plains), its members would have likely seen only a fraction of the wildlife that they saw in September (one of the driest months).  We’re fortunate they arrived when they did, because we now know, through their journals, of the incredible variety and vast number of creatures that lived in and around the Missouri Valley in the early nineteenth century.

After Lewis and Clark returned to St. Louis, the two men advised prospective fur traders on the best sites for the establishment of trading posts within the Missouri Valley.  Armed with this information, the Missouri Fur Company established a post in 1809 in the Oacoma Bottom – it’s purpose – to trade with the Teton Lakota for furs, especially that of the beaver.  This post lasted only a year before burning to the ground.[7]

Not until the end of the War of 1812 did the Upper Missouri fur trade kick into high gear.  In subsequent decades, large trading posts and smaller, temporary trading houses arose in the bottoms, many in the vicinity of Oacoma.  Fort Pierre, Fort Clark, and Fort Union became lasting fixtures of the fur trade, each of those posts built atop a bottom.

In the early years of the trade, keelboats and pirogues carried supplies and laborers to the posts.  But in the 1840s, keelboats disappeared along the Missouri, replaced by the faster, larger, and more cost-effective steamboat.

The fur trade, and the steamboat traffic that supported it, fundamentally changed the hydrology and ecology of the Missouri Valley and northern plains.  The fur trading posts, and the men who worked within their walls, prevented bison and other species from using the bottoms during the height of summer and the depths of winter.  Forced to remain on the wide-open plains during the most difficult months of the year, species suffered higher mortality rates.

The fur trade also decimated the beaver population on the lands between the Missouri trench and Continental Divide.  How many of the animals inhabited that area prior to the fur trade is unknown.  But the number may have been astronomical – in the millions.  Removing the beaver from the scene had unintended consequences.  Hundreds of thousands, perhaps millions, of beaver dams fell into disrepair in the decades after 1815.  As a result, more rainfall and snowmelt flowed into the Missouri, and at a faster rate, forcing the stream to rise higher than it did in the past.  These higher, and more frequent, flood flows rearranged the valley’s habitat mosaic – washing away islands, submerging sandbars, and toppling timber stands.

The loss of beaver ponds not only influenced the Missouri’s hydrology, it harmed all of the species dependent upon the water in those ponds.  Birds, fish, reptiles, amphibians, and mammals lost an important source of water. No longer able to access the beaver ponds, creatures either perished or tried to migrate to comparable areas – such as the Missouri River bottoms.  These attempted migrations happened at the very same time the bottoms came under increasing human pressure from fur traders and steamboat crews.

The steamboat may have been a technological marvel of the age, but it came at great ecological cost.  Steamers went up the Missouri in March and April, riding on the high water of the Spring Rise.  The northbound boats passed through the Upper Missouri Valley just as the calving season came to an end. Newborn elk, bison, and deer huddled with their mothers in the bottoms at this time of the year.  The boats made such a racket as they rattled and thumped their way upstream that creatures fled to the highlands to escape the strange sounds.[8]  Once on the uplands, in the open, the young fell prey to both the weather and wolves.

To add to the woes of the wildlife, crews on board the steamers all-to-frequently shot anything that lacked the wits to flee. And if all of the commotion and gunfire that accompanied the passage of the steamers were not enough of a disruption, the steamers regularly docked at the bottoms to gather wood.  Once a boat reached shore, dozens of gun-toting passengers and crewmen disembarked, transforming a forest that minutes before had been quiet, or pierced only by the gentle notes of bird song, into a place of sound and fury.

The steamboats consumed huge quantities of timber. Crews procured all of the fuel for the boats from the valley itself.  Each boat burned an average of 25 cords of wood per day.  A single steamer working the river between March and November might burn thousands of cords. Not surprisingly, the steamboats fostered severe deforestation, especially in the river reach between the Platte and Yellowstone.  As early as the mid-1840s, river travellers noted the paucity of wood.  That absence compelled steamboat crews to desperate measures.  On May 21, 1843, at the mouth of the Niobrara River, Edward Harris, who was traveling on board the steamer Omega, recalled the actions of the boat’s roustabouts.  “…here we found a Fort (Fort Mitchell) which had been abandoned on account of the high waters and our folks went to work pulling down the stockades for fuel for the boat and carried off some furniture which was left in the houses.”[9]  In the 1850s, the lack of valley timber became acute.[10]

Trees store water in their leaves, branches, trunks, and roots.  Stands of riverside timber act as small catch basins – holding water back from the Missouri.  They also serve as buffer strips, slowing or stopping surface runoff from entering the river.  Trees even stabilize the banks, slowing the stream’s propensity to wander across the valley floor.

At the same time that the valley’s forests vanished into the furnaces of the steamboats, a series of floods came charging down the Missouri.  The most voluminous Missouri River floods in the nineteenth century coincided with the steamboat era.

We cannot prove that the deforestation that accompanied the steamboat era caused successive floods along the Missouri.  Nevertheless, we can assume that deforestation worsened the flooding. Knocking down the valley’s forests had to have had an influence on the river’s flow volumes.

Floods struck the Missouri Valley in 1844, 1857, 1858, 1867, 1872, 1874, 1875, 1878, and 1881.  During those same years, the river’s morphology changed noticeably.  When Lewis and Clark went up the Missouri, the river south of today’s Yankton flowed through its valley in long, relatively-narrow loops.  By the 1880’s, the lower river had become straighter and wider (or what hydrologists call a “semi-braided stream”) in order to carry the higher flows moving through its channel area.[11]

In the nineteenth century, European-Americans radically altered the Missouri’s hydraulic regime.  Weather phenomena played a role in that transformation, but the near-extinction of the beaver, along with deforestation, delivered a one-two punch to the river, pushing it higher than otherwise would have been the case.  Those higher flows altered the river’s morphology, rearranged the valley’s habitat, and damaged European-American settlements further downstream.

During the steamboat era, European-Americans relied on the river as a transportation route and as a source of food, furs, timber, and fodder.  When the railroad reached the river, settlers turned away from the Missouri and its by-now depleted resource base, relying instead on the railroad for many of life’s necessities – and a few of its luxuries.

In 1894, the Missouri River Commission published detailed maps of the Missouri Valley.  Map 37 in the series shows the Oacoma Bottom and vicinity.  Much had changed since Lewis and Clark’s visit ninety years earlier.  A cemetery, a federal post office, and the Lower Brule Indian Agency occupied the south-western corner of the terrace.  A smattering of small trees grew near the mouth of American Crow Creek before it emptied into the Missouri near the agency headquarters.  To the north and east, a road skirted the edge of the bottom where it met the bluffs, connecting the Indian agency with a pontoon bridge that crossed the Missouri to Chamberlain – the terminus for the Chicago, Milwaukee and St. Paul Railroad.  In the following decade, the railroad reached the river’s west bank, passed through the tableland north of the Oacoma Bottom, and then swung westward up the valley of American Crow Creek.

The commission map provides no information on what animals lived at or near Oacoma.  Nevertheless, we know the bison and beaver were long gone; and elk, deer, pronghorn, and wolves were in decline.  The prairie dog – an animal with no value in American meat or fur markets – may have still lived at Oacoma – but it was considered so inconsequential that no one left a record of its presence.[12]

By the time of the publication of the Missouri River Commission maps, Missouri Valley residents had begun to view the river as a wasted natural resource and a threat to their way of life.  Politicians from Missouri to Montana shared that perception.  Beginning in the 1880s, the business elite in the valley’s urban centers, and their federal and state representatives, lobbied Congress to develop the river for hydropower, irrigation, flood control, and barge navigation – with the goal of making the Missouri useful to an industrializing and urbanizing nation.

The lobbying efforts paid off.  Between 1891 and 1940, the Army Corps of Engineers, in fits and starts, constructed a six-foot barge channel in the river from the mouth to Sioux City. Then, during the Dirty Thirties, the Army built Fort Peck Dam to supply water to that six-foot channel.  Soon after the completion of those two public works projects, floods returned to the Missouri.

The Missouri flooded south of Sioux City in 1941, 1942, 1943, 1944, 1947, 1949, 1950, 1951, and 1952.  The Army’s narrow barge channel exacerbated the flooding – as did Midwestern farmers, who had increased their crop acreage to meet the wartime emergency.  Lacking the conveyance capacity to safely pass the floodwaters downstream, the barge channel forced the river up and out.  Freed from the pile dikes and revetments hemming it in, the Missouri ran wild.  Its fast-moving waters slashed deep gashes across the valley floor, undermined roadways, and carried away farmhouses.   The loss of ground cover to cropland increased runoff into the stream – adding to the height of the flood crests and the destructive power of the floodwaters.[13]

To halt flooding south of Sioux City and to prevent the barge channel from being completely destroyed by the Missouri’s high flows, and to provide hydropower and irrigation water to the residents of the northern plains, the Army and the Bureau of Reclamation proposed the construction of dams across the Missouri main-stem in North and South Dakota.  The legislation authorizing those dams became law in December 1944.

On July 20, 1952, the Army closed the embankment at Fort Randall Dam in southeast South Dakota.  Not long afterward, Fort Randall’s reservoir began filling with water.  By September 1953, the reservoir was rising at the rate of six inches per day.  In September 1954 – a 150 years since Lewis and Clark’s visit – the cold, grey waters of the dammed river approached the Oacoma Bottom.  By the end of 1955, the once “butifull Plain” at Oacoma lay silently beneath the wind-ruffled surface of the reservoir.[14]

At the same time the Army bulldozed mountains of dirt across the path of the Missouri in the Dakotas and filled its main-stem reservoirs, it rebuilt the barge channel south of Sioux City – this time to a depth of nine-feet.  When completed in 1980, the narrow barge channel eliminated almost all of the lower Missouri’s islands, sandbars, sand flats, and side channels.  Only 57 acres of sandbar and island habitat remained along the river reach through western Iowa and eastern Nebraska upon the completion of the barge channel, this compared to an estimated 9,757 acres of island habitat and 14,790 acres of sandbar habitat along the same reach a hundred years earlier.[15]  Upstream, the Dakota dams, plus Fort Peck, divided the river into six distinct segments and drowned over 750 miles of river valley.

Encouraged by the Army to believe the Missouri had been irrevocably confined behind rock and reservoirs, the American people moved ever closer to the river.  They erected their interstate highways, factories, power plants, gated communities, farms, RV parks, wastewater treatment facilities, hotels, strip malls, fast-food restaurants, parking lots, and warehouses next to the barge channel or alongside one of the upstream reservoirs.  In the late twentieth and early twentieth-first centuries, all the lit-up, loud, super-sized accoutrement of modern America crowded in on the river.  The last remnants of habitat fragmented into a thousand little pieces. Songbirds disappeared. Insects vanished. Forests fell.  Deer fled. Fish diversity plummeted. Invasive species took hold and did not let go.

And then the unthinkable happened, the earth warmed, the rains came, and the Missouri flooded – again and again.  In 1971, a major flood struck the lower valley – the first since all the Dakota dams went on-line.  Floods followed in 1973 and 1984.  In the summer of 1993, the lower river rose higher than at any time since the super flood of 1952.  Non-stop thunderstorms, the tiling of agricultural lands, increasing suburbanization, the drainage of valley wetlands, the straightening of the Missouri’s tributaries, the laser-levelling of cropland, the compaction of soil by heavy farm equipment, and the “asphaltification” of land to accommodate The Car meant rainwater had nowhere to go but into the Missouri.  Kept out of its floodplain by its riprapped banks and a system of levees, the Lower Missouri rose until it overtopped both the barge channel and the levees; it then cascaded down into towns such as Hamburg, Iowa.

Although the flood of 1993 should have led to the dismantling of the barge channel between Sioux City and Kansas City, and the realignment of levees, powerful interest groups insisted on the reconstruction of both.  Not surprisingly, the Army obliged those interests, rebuilding both the barge channel and the levee system.  More floods descended the Missouri in subsequent years, but no one dared tackle the root causes, because to do so would have impinged on somebody’s bottom line.

In 2011, a record 61 million-acre feet of runoff entered the river north of Sioux City.[16]  All of the factors that fostered the Flood of 1993 were there in 2011, plus an additional one.  Spurred on by high commodity prices, farmers in the Midwest and Plains states had in the previous decade converted millions of Conservation Reserve Program (CRP) acres to cropland.  The new corn and soybean fields lacked the absorption capacity of the CRP acres.

Nothing could contain the ocean of water that ran into the Missouri that year, not even the Army’s main-stem reservoirs.  To prevent the structural failure of its big dams, the Army leadership in Omaha decided to drain the reservoirs as fast as possible, dumping a “controlled flood” into the valley south of Yankton.  Incredibly, after this unprecedented deluge, the Army again rebuilt the flood-prone barge channel and levee system south of Sioux City.

In 2016, the Bureau of Reclamation published a report on the probable effects of climate change on the Missouri.  The report concluded that the Missouri would become more erratic in the years ahead, with higher highs and lower lows.  Most importantly, the river would experience dramatic rises on short notice – the consequence of warming temperatures, the rapid melting of snow cover, and/or heavy rainfall events.  On the other extreme, more frequent and intense drought episodes would lead to water shortages for municipalities, irrigationists, and power plant operators.[17]

Lewis and Clark envisioned the Missouri River Valley as a transportation route, a source of furs, the future site of European-American settlements, and as a means of projecting military power into the northern plains and Rocky Mountains.  The two men never once considered leaving the river and valley as they found it – as a place rich in biological diversity and a source of sustenance for native cultures.  In that regard, Lewis and Clark were radicals, men bent on overturning an ancient ecological order and the indigenous societies sustained by that order.

In the nineteenth century, fur traders and trappers, steamboat owners and operators, railroad men, and agricultural settlers fulfilled Lewis and Clark’s vision for the Missouri River and its drainage basin.  In the twentieth century, the American people took Lewis and Clark’s vision even further, transforming the Missouri so thoroughly that it became as much a human artifice as a natural one.

History possesses weight, mass, and momentum.  For over two centuries, the Missouri, its basin, and its people have been on a course first launched by Lewis and Clark.  There is nothing in the foreseeable future that will alter that course.  Granted, the Army may open additional side channels south of Sioux City to lessen the flood threat, and the least tern, piping plover, and pallid sturgeon may be saved from near-term extinction, but those actions will not fundamentally redirect the Missouri from its 215-year-old trajectory.

Today, the four, gleaming-white, concrete lanes of Interstate 90 cross the Missouri at Chamberlain, touch the western shore of Lake Francis Case, and then make a graceful turn to the southwest, passing within a half mile of the long-drowned Oacoma Bottom.  A motorist approaching Oacoma from the northeast first passes three wastewater ponds on the left; then, a little further on, and on the right, a Baymont Hotel, a strip mall named Al’s Oasis (with three artificial bison out front), an RV park, and a slew of billboards, including one advertising for the Golden Buffalo Casino – “Your Winning Destination.”  The majority of the town’s 451 residents (2010 Census) live in modest houses and trailers on the riverward side of the highway, within earshot of the constant hum of high-speed traffic.

If you travel to Oacoma, take Exit 260, turn south on Dougan Avenue, rumble over the railroad tracks, stay on the road until it turns to gravel and reaches a “T” intersection, turn left, pass two gravel roads on the right, turn right onto the third gravel road.  Drive until you reach the edge of Lake Francis Case.  Stop.  Get out of your vehicle and walk up to the riprapped embankment.  From there, in every direction, you can see the legacy of Lewis and Clark.


[1] David McCullough, Mornings on Horseback: The Story of an Extraordinary Family, A Vanished Way of Life, and the Unique Child Who Became Theodore Roosevelt, (New York: Simon and Schuster, 1981), 349.

[2] Gary E. Moulton, ed., The Journals of the Lewis and Clark Expedition, Volume 3, August 25, 1804 – April 6, 1805, (Lincoln: University of Nebraska Press, 1987), 77.

[3] Gary E. Moulton, ed., The Journals of the Lewis and Clark Expedition, Volume 9, The Journals of John Ordway, May 14, 1804 – September 23, 1806, and Charles Floyd, May 14 – August 18, 1804, (Lincoln: University of Nebraska Press, 1995), 60.

[4] Moulton, The Journals, Volume 3, 81.

[5] Melvin R. Gilmore, Uses of Plants by the Indians of the Missouri River Region, Enlarged Edition, (Lincoln: University of Nebraska Press, 1991), 22-37.

[6] Max Heinze, Artist, Missouri River, (St. Louis?: Missouri River Commission, 1894), Map XL.

[7] Richard Edward Oglesby, Manual Lisa and the Opening of the Missouri Fur Trade, (Norman: University of Oklahoma Press, 1984), 97; Gary E. Moulton, Editor, The Journals of the Lewis and Clark Expedition, Volume 1, Atlas of the Lewis and Clark Expedition, 1983), Map 20.

[8] Reuben Gold Thwaites, ed., Early Western Travels, 1748-1846, Vols. 22-24, Maximilian, Prince of Wied’s Travels in the Interior of North America, 1832-1834, (New York: AMS Press, 1966), 22: 268, 334, 366.

[9] John Francis McDermott, Editor, Up the Missouri with Audubon: The Journal of Edward Harris, (Norman: University of Oklahoma Press, 1951), 68.

[10] John Francis McDermott, Editor, Journal of an Expedition to the Mauvaises Terres and the Upper Missouri in 1850, by Thaddeus A. Culbertson, Smithsonian Institution, Bureau of American Ethnology, Bulletin 147, (Washington: GPO, 1952), 88.

[11] George R. Hallberg, Jayne M. Harbaugh, and Patricia M. Witinok, Changes in the Channel Area of the Missouri River in Iowa, 1879-1976, (Iowa City, Iowa: Iowa Geological Survey, 1979), 10.

[12] J.C. Barr, Artist, Missouri River, (St. Louis?: Missouri River Commission, 1894), Map XXXVII.

[13] Pierre Capital Journal, “Corn, Soybeans Dominate SD Planted Acres, While Wheat Acres Have Dwindled,” Stephen Lee, September 25, 2017; Gerald Miller, Aaron Sassman, and C. Lee Burras, “Iowa Corn and Soybean Acres Planted, 1927-2016,” (Ames: Iowa State University, Agronomy Department, January 17, 2017).

[14] Department of the Army, U.S. Army Corps of Engineers, The Federal Engineer, Damsites to Missile Sites: A History of the Omaha District, U.S. Army Corps of Engineers, (Omaha: U.S. Army Corps of Engineers, Omaha District Office, 1984), 110; Omaha World Herald, “Randall Lake Grows Fast,” October 17, 1954.

[15] Hallberg, et.al., Missouri River, 1879-1976, 32.

[16] Sioux City Journal, “Missouri River Runoff Forecast to be Above Average,” Nick Hytrek, March 7, 2019.

[17] Bureau of Reclamation, Secure Water Act, Section 9503(c), Reclamation, Climate Change, and Water, 2016, “Chapter 6: Missouri River Basin,” (Denver: U.S. Department of the Interior, Bureau of Reclamation, March 2016), 6-10 – 6-11.

This entry was posted in Uncategorized and tagged , , , , , , , , , , , , , , . Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Footer Divider


Follow Us

Join Mailing List

Contact Us

If you wish to contact Eco InTheKnow, please email us or contact us on the number below.

1303 596 1854