Understanding hydrogeomorphic history to restore, manage and protect the lower Missouri River
The lower Missouri River, the largest free-flowing river reach in the United States, encompasses nearly 1.5 million acres of bottomland habitat for fish, wildlife and plants, while providing commercial transportation and recreation opportunities for communities across our nation’s heartland.
Two centuries ago the lower Missouri River, nicknamed the Big Muddy, provided up to a mile-wide braided channel of riverine and floodplain habitat. But more than 200 years of urban development, flooding, agricultural expansion, and human exploitation for navigational, recreational and commercial use have permanently altered the river’s character.
Conservation forces across federal, state and non-governmental agencies and organizations are committed to uncovering layers of Big Muddy’s past to set a course for future restoration and management of this regulated, yet untamed river system.
The method uses hydro-geomorphologic characterization, a landscape-scale analytical technique that has been applied across major North American river systems including portions of the Colorado, Arkansas and Mississippi rivers, to help land managers preserve existing and restore potential fish and wildlife habitat. Now, researchers aim to use the process to inform more effective conservation and management across 670 miles of the Missouri River from Decatur, Nebraska to St. Louis, Missouri, as part of the Lower Missouri River Hydro-geomorphic Restoration and Management Project.
Natural resource researcher and private consultant Dr. Mickey Heitmeyer is leading the effort to pull together quantitative data on the hydro-geomorphic attributes of the lower Missouri River prior to European settlement.
“We want to know how the Missouri River was formed, its shape, characteristics of the floodplain, and how that has changed over time,” Heitmeyer said.
Today, the lower Missouri River is highly influenced by upstream reservoirs and water control that affect the river’s physical and ecological functions. These alterations pose significant challenges for those that live and make their livelihood along the river, as well as for the maintenance and protection of wildlife habitat.
Engineers and ecologists are working alongside Heitmeyer to analyze both historic and contemporary information about physical features of the lower Missouri River, ranging in scale from site-specific tracts on national wildlife refuges to large watersheds and floodplains.
“We are gathering the data in layers, piecing together the geology, soil structure, topography, and finally, the hydrology of the river. What was the nature of the river before it was altered, including its dynamics, and seasonal and long-term patterns?” Heitmeyer said. “Once we have that data, we map it, layer over layer, and compare it to current day conditions.”
The U.S. Fish and Wildlife Service’s (USFWS) Division of Biological Resources partnered with the Eastern Tallgrass Prairie and Big Rivers Landscape Conservation Cooperative (LCC) and Plains and Prairie Potholes LCC to co-fund the project. The Division of Biological Resources provides robust, defensible and transparent scientific information and assistance to the National Wildlife Refuge System, while LCCs are partnerships that seek to bridge the gap between science and natural resource management.
“This is a partnership that we are very proud of and we feel reflects the overlap of landscape scale conservation priorities between the National Wildlife Refuge System and the LCCs,” said Josh Eash, USFWS regional refuge hydrologist.
The research will not only benefit refuge managers, but will also provide valuable data that can be used by managers across a broad spectrum of publicly and privately owned lands throughout the floodplain.
“We want to ensure the Big Muddy remains home to vibrant and diverse fish and wildlife species, while continuing to benefit future generations of river communities,” said Rick Nelson, coordinator of the Plains and Prairie Potholes LCC. “By bridging the science behind the lower Missouri River landscape with all types of land managers, we can work toward more objective and scientifically sound conservation of this dynamic natural resource and the fish, wildlife and people it supports.”
Nelson and Eash agree that taking a landscape scale approach to conservation efforts and management decisions is crucial to addressing long-term natural resource challenges, from impacts of climate change to shifts in agricultural practices. Through this collaborative effort, land managers within the lower Missouri River floodplain can visualize the river in its pre-settlement state to help set conservation and management objectives for the future.
“If we know the geology, the soils, elevations, and flooding patterns, then we can get a sense of what plant communities were historically there, what attributes caused them to be there, their distributions, and what physical features caused them to be sustained over time,” Heitmeyer said.
Refuge managers like Tom Bell of the Big Muddy National Fish and Wildlife Refuge in Missouri, are anxious to use results from the project to help inform restoration and acquisition actions for the refuge.
“This research will allow us to look at subsurface maps of ancient Missouri River features within the floodplain,” said Bell. “We will physically be able to see where surface topography will either promote or hinder wetland restoration, so we’ll be able to make better decisions on restoration activities and locations.”
Big Muddy National Fish and Wildlife Refuge, with units dotting portions of the Missouri River from St. Louis to Kansas City, was established following the flood of 1993 when private landowners sold more than 16,000 acres of floodplain for permanent protection to the federal government. The USFWS has approval through Congress to acquire up to 60,000 acres of floodplain and adjacent land on the Missouri River between St. Louis and Kansas City.
“We have the opportunity to get ahead in our strategic planning for restoration and acquisition of lands for the refuge, rather than learning by trial and error as we have done in the past,” said Bell.
Heitmeyer said that managers at national wildlife refuges and wetland management districts will be able to zoom into specific tracts of land to visualize historic hydrogeomorphic traits and overlay that visual with present-day conditions. “By visualizing the historic vegetation, natural resource managers can also determine, by default, the animal communities that were historically supported there,” he said.
Tom Cox, refuge manager at DeSoto National Wildlife Refuge, which straddles the Iowa-Nebraska border, said Missouri River refuges are home to a broad spectrum of floodplain-dependent fish and wildlife species.
“That’s why science-based decisions about land acquisition, and restoration and management is critical to how we do business in the future,” Cox said. Cox plans to use the results of the Hydro-geomorphic Restoration and Management Project to help plan restoration activities that benefit existing wildlife populations on the refuge, and have the potential to augment habitat for species in decline.
“When I came to DeSoto we were looking at serious declines in waterfowl numbers, a drop as much as 75 percent over historic long range numbers,” Cox said. “We have thousands of acres of hydric soils, so we are using wetland restoration as a key tool to bring back the ducks, and a host of other species from secretive marshbirds to shorebirds.”
Floodplains are also important spawning sites for numerous native big river game and non-game fish species, including the federally endangered pallid sturgeon. Natural and man-made channels also benefit resident and migratory shorebirds and waterfowl, including the federally listed piping plover and interior least tern, which utilize sandbars for nesting, breeding and foraging.
Cox explains that shifts in agricultural practices over time on surrounding refuge lands have changed the diversity of wildlife on the refuge. “We know that we will never be able to restore the natural ecosystem as it existed in the past because of artificial manipulation of water levels, so we have to be more strategic and creative in our wetland restoration efforts,” he said. “The hydro-geomorphic study can open our eyes and give us a range of options for restoration activities.” Wetland restoration on the refuge has contributed to a four-fold climb in waterfowl populations over the past decade.
Refuges that adjoin stretches of the river are also common destinations for visitors from the Midwest and across the U.S. Birders, wildlife photographers, nature enthusiasts and hunters and anglers alike, frequent Missouri River refuges during spring and fall bird migrations and hunting and fishing seasons.
“Our management decisions on the refuge impact more than just wildlife. Our job is to help sustain fish and wildlife populations and protect habitat for declining species, but, we also recognize the economic and intrinsic value of these natural resources,” Cox said. “Healthy habitats for fish, birds and other wildlife contribute to local economies by providing outdoor recreation activities enjoyed by many people.”
Boyer Chute National Wildlife Refuge in eastern Nebraska and Squaw Creek National Wildlife Refuge in northwest Missouri, also positioned along the lower Missouri River corridor, will also be able to use mapping tools developed by the Hydro-geomorphic Restoration and Management Project to inform acquisition and restoration activities in relation to contemporary flood control, reservoir regulations, policies, and other management considerations impacting refuge and surrounding lands.
The reality, as Heitmeyer, Bell and Cox attest to, is that returning river habitat to pre-settlement condition is simply not feasible under these current environmental conditions and stressors.
“So the final step in the process is evaluating management or restoration options in the current, real-world environment,” Heitmeyer said. “We have forests, ditches, levees, roads and other impediments to restoration that land managers must consider, in addition to the economic considerations of land-use.”
Despite the dynamic changes experienced by the Big Muddy over the last two centuries, project partners are optimistic about the restoration and management potential of this landscape approach to data collection and research. By bridging the gap between science and natural resources management along the Big Muddy, land managers can more successfully protect, manage, conserve and restore portions of this biologically diverse, economically significant, and ever-changing river system.
“This is really where the rubber meets the road. We are forming a template for refuge managers to make decisions about restoration projects and species conservation efforts in light of historical and contemporary conditions,” Heitmeyer said. “By doing this from St. Louis to Omaha we are thinking about the entire system and will get a sense of an entire stretch of river at a landscape scale. Our job is to put the refuge in the right context relative to the whole region.”
The lower Missouri River Hydro-geomorphic Restoration and Management Project received $100,000 in funding from the Plains and Prairie Potholes LCC and Eastern Tallgrass Prairie and Big Rivers LCC, and, an additional $150,000 from the USFWS Division of Biological Resources. The project is anticipated to take 2.5 years to complete.
Image courtesy U.S Fish and Wildlife Service