Bagnell Dam, on Lake of the Ozarks. - FWS photo

Lake of the Ozarks is known as a prime destination for anglers, boaters, and outdoor recreationists from around the country.  Located in south central Missouri, the lake was formed with the 1931 completion of Bagnell Dam on the Osage River.

While the lake offers more than 55,000 acres of surface water and 1,150 miles of shoreline for recreation enthusiasts, the presence of the dam and hydroelectric facility creates challenges to fish and wildlife resource managers, particularly in the Osage River downstream from the dam. 

Among the concerns are altered flow regimes, bank and channel erosion, impacts on aquatic habitats, low dissolved oxygen, fish mortality at the dam, and negative impacts on freshwater mussels including two federally endangered species.

These challenges were met early and head on by Missouri Ecological Services as AmerenUE applied for a new license from the Federal Energy Regulatory Commission (FERC).  The Service and other stakeholders began working with AmerenUE in 1999, concentrating its efforts on impacts to fish and mussels in the lower Osage River and fish protection in the lake. 

With the Missouri Department of Conservation, Missouri Department of Natural Resources, and the National Park Service, the Service and AmerenUE worked together to implement studies to better understand the fish and wildlife impacts of the existing hydrowpower facility and development of measures to mitigate these impacts.   

The lower Osage River supports populations of native Ozark stream fish as well as big river species, some of them of special concern, such as the paddlefish, and sturgeon.  The lower river is also among the most important mussel streams in Missouri.  Thirty nine mussel species have been found in the river, including two federally listed species (the pink mucket and the scaleshell), one federal candidate, and several species of conservation concern.  The pink mucket population in the lower Osage River is one of the most significant in the species’ range and is the largest population west of the Mississippi River.

Through intensive negotiations, the federal and state resource agencies and AmerenUE developed a settlement agreement that satisfies all major environmental concerns while providing for energy needs, protecting critical lake levels for recreation, and addressing downstream landowner needs. 

In March 2007, the Federal Energy Regulatory Commission issued AmerenUE their new license, which incorporated all the conservation provisions of the settlement agreement. The key conservation measures provided by the license include improved stream flows and increased minimum flow in the 80 miles of the Lower Osage River.  This provides spawning flows, seasonal variations, and flows that will increase aquatic habitat for downstream species, including endangered mussels.

In addition, the conservation effort will increase dissolved oxygen levels in the lower river during project operations, enhancing conditions for mussels and fish. Additional conservation measures will be taken to reduce bank and channel erosion during flood flows. Fish protection tactics will be improved, including the addition of a barrier net that reduces or prevents fish mortality due to turbine or dam operation.

The plan will result in enhanced fish production for Lake of the Ozarks and restoration of mussel populations through artificial propagation. Two additional conservation programs will be implemented benefiting aquatic and terrestrial habitat. The aquatic habitat and species restoration and enhancement program will focus on mussels and their habitats in the lower 80 miles of the Osage River, while a shoreline management plan will protect terrestrial habitat used by bald eagles for nesting and roosting.

According to Charlie Scott, Field Supervisor of Missouri Ecological Services “our efforts on the Bagnell Dam hydropower relicense are typical of other large water actions that all Ecological Services Field Offices frequently participate in through its Habitat Conservation Program.”  

Missouri Ecological Services biologists, working with the licensee, State counterparts, and other key conservation partners expended considerable time and effort over an extended time period to document impacts and formulate effective and creative solutions.  Although this effort took over seven years to complete, the benefits to fish and wildlife resources and the citizens of Missouri are monumental.   

Scott noted that “the implementation of these conservation measures over the next forty years is a major milestone in restoring the aquatic ecology and biodiversity of the entire lower Osage River.”