Port Louisa National Wildlife Refuge and Odessa WMA
The 6,465 acre Odessa Wildlife Complex is a unique backwater habitat of the Mississippi River located in southeast Iowa at the confluence of the Iowa and Mississippi Rivers near Wapello, Iowa. The Odessa Complex is owned by the U.S. Army Corps of Engineers but management of the area has been out-granted to the U.S. Fish and Wildlife Service and the Iowa Department of Natural Resources.
Odessa is divided into the 2,326 acre Port Louisa National Wildlife Refuge (Louisa Division), managed by the U.S. Fish and Wildlife Service, and the 4,139 acre Odessa Wildlife Management Area , managed by the Iowa Department of Natural Resources.
Shallow water is ideal for migrating waterfowl. Shallows warm up early and produce an abundance of invertebrates, which are the most important food of spring-migrating dabbling ducks. Shallow water also avoids saturation of tree roots and allows germination and growth of trees and other plant seeds on the higher ground. Shallow water is also important for feeding waterbirds like herons, egrets and pelicans along with reptiles and amphibians. Often, spring floods will raise the water to a level that is more than desirable for optimum wildlife use.
Lowering the water level in the summer exposes over a thousand acres of mudflats which are heavily used by shorebirds. These areas quickly germinate with a variety of moist soil plants, such as millets and sedges, that produce heavy crops of seeds that will be consumed by migratory waterfowl during fall and spring migrations, and are the main substrate for the following spring’s invertebrate populations. It also allows sprouting of additional buttonbush plants from exposed rootstock and germination of perennial wetland plants like arrowhead, bulrush, and lotus. Lowering the water level is also important for tree root growth and maintaining the health of the forest resource on Odessa. The remaining shallow water in the complex is heavily used by wading birds, as well as snakes and turtles. Often, prolonged summer flooding on the Mississippi and Iowa Rivers will delay or prevent the lowering of the Odessa water level, limiting the amount of annual food and cover that is produced.
The water level at Odessa is slowly raised throughout the fall. Gradually increasing the water level will continually make new habitat available to migrating waterfowl as the fall progresses and thousands of ducks, geese and other migratory birds use the cover, seeds produced, and invertebrates that are abundant in the moist-soil vegetation.
Water is returned to a moderate level to minimize ice damage to shorelines, trees, buttonbush and other vegetation. It also prevents saturation of tree roots over winter. When possible, the inlet and outlet structures are opened to allow water to flow through the system to maintain acceptable levels of dissolved oxygen for fish, and also to maintain a few small areas of open water for migrating waterfowl.
The DNR-managed Odessa WMA is open to public hunting and has been a very popular waterfowl hunting location for many decades. A controlled waterfowl hunting program was operated for about 40 years but was eliminated after the 2009 season because reduced hunter numbers no longer warranted the special restrictions. Odessa now falls under the standard statewide wildlife management area hunting regulations. Most waterfowl hunters use blind boats as much of the area is only accessible by boat, however, there are some good walk-in hunting opportunities at the south end of the WMA. Deer, turkey and squirrel hunting are also popular on the area.
The Port Louisa National Wildlife Refuge is always closed to hunting and closed to all public use from September 15 until January 1. It provides sanctuary and food for the thousands of migratory birds that pass through the area. There are hunting opportunities available on other lands managed by the USFWS located nearby. Port Louisa NWR information can be found online.
Sport fishing is allowed all year in accordance with state seasons and regulations except the Port Louisa refuge is closed to public use from September 15 until February 1 (except the inlet area which is open to public use year around).
Odessa has an excellent fishery for catfish, crappie, and bluegill, but almost anything found in the Mississippi River can be caught in Odessa because of the frequent connection to the river due to Odessa’s water control structures and frequent flooding. Odessa's shoreline is all public land, so there are opportunities for bank fishing. Three boat ramps provide boat access for anglers. The inlet area of the Port Louisa refuge is an especially popular bank fishing area when water is being let in from the river. The area around the outlet structure on Odessa WMA is also popular when water is flowing out of the complex.
Snively Access Campground, on the shores of Odessa, is managed by the Louisa County Conservation Board and is Louisa County's most popular campground.
Boating opportunities on Odessa are many and can vary throughout the season based on water levels.
There are three access points with boat ramps and many miles of backwater chutes, sloughs and ponds to explore, in addition to the large open water main lake. Several water trails are marked for paddlers. Although it's a shallow system, paddlers and flat-bottomed boats with small outboards can still run several miles at even the lowest water levels.
To protect the fragile shore from erosion due to wave action there are several no-wake areas on the complex, including the entire refuge.
Generally the water level is highest during the spring, early summer, and mid to late fall, with the lowest water levels generally occurring from mid-summer through early fall. Odessa is greatly influenced by the Mississippi River and Iowa Rivers and water levels can vary dramatically from year to year.
The Odessa Complex is centrally located along the Mississippi Flyway, a major route for migratory birds, affording visitors an excellent opportunity to see wildlife throughout the year. Over 200 species of birds visit the Complex throughout the year with October, November, March, and April being the best months to see large concentrations of waterfowl. Warbler migrations usually peak around the first week of May. August is usually the best viewing time for shorebirds. Bald eagles are common in fall and winter and increasingly common in spring and summer as nesting increases on the complex.
Herons, pelicans and egrets are commonly seen during the summer feeding in Complex wetlands. Deer, squirrel, raccoon, muskrat, turkey, otter, beaver, skunk, and opossum are year-round residents, but not always easy to spot.
Shorelines are a good place to look for most of these species while boating or paddling the area, in addition to the wide variety of turtles, frogs and snakes found here, including some that are state listed as endangered or threatened species.
There are also several observation decks located at the Port Louisa refuge with spotting scopes that allow for viewing of the refuge.
As part of the Mississippi Flyway, the Odessa complex contributes scarce, high quality migration habitat in a landscape dominated by agricultural production. The Mississippi Flyway is a globally significant flyway for 60% of all North American bird species and provides a major route used by shorebirds, ducks, geese, blackbirds, warblers, sparrows, and thrushes. It contains the longest migration route of any route spanning the Western Hemisphere, more than 3000 miles from the mouth of the Mackenzie River to the delta of the Mississippi River. This flyway supports an average of 36 percent of all ducks in the contiguous United States and most of the mallards in North America use the flyway. Most North American land birds that winter in the tropics also use this flyway.
The Odessa complex represents a small fragment of the vast expanse of shallow wetlands that covered the Mississippi River floodplain when European settlers began arriving in the early 1800s. In those days, spring floods spread out over the entire floodplain and filled thousands of shallow basins and sloughs scattered from bluff to bluff. Many of those basins would dry during late spring and summer, and a variety of wetland plants would germinate and grow in them. Depending on depth and soils, some would be dominated by perennial plants like cattails, bulrush or buttonbush, and others would grow annual seed-producing plants like smartweeds and millets. Normal fall rains produced a slight rise in the river that filled many of those basins again, making all that seed available to migrating waterfowl. In the spring, those heavily vegetated basins produce an eruption of tiny aquatic organisms, including insect larvae, tiny crustaceans, and others that biologists refer to generally as invertebrates. They supply spring migrating waterfowl a crucial source of protein for their northward journey, especially to hens building energy reserves for egg laying. Ideal conditions wouldn't have been present everywhere on the river every year, but because of the vast resources stretching its length from bluff to bluff, vast areas would have been present for birds to refuel on their migration. Today, the river and floodplain are now a completely different system. The river has been reduced to a narrow ribbon cut off from most of the floodplain by adjacent levees, and drainage systems keep most of the floodplain dry year around for agriculture and other development. The river itself has been converted to a series of impoundments by the navigation dams, and while it still floods, the drying cycle has been eliminated and so too has most of the wetland vegetation that once sheltered and fed migrating waterfowl.
At the Odessa Complex, managers have a unique opportunity to mimic the historic water level fluctuations that produce everything the waterfowl and other migratory birds need during their migrations. An inlet structure above Lock and Dam 17 allows water to flow in from the pool, while an outlet structure below the dam allows water to be drained into the lower pool 18. The normal operation is to slowly drain water out of the Complex once the spring flooding is over to reach the lowest levels by mid-summer when nearly a thousand acres of mudflats are exposed. Those mudflats will sprout a profusion of seed-producing moist soil plants if water is kept off them for a month or so. When the water is slowly raised throughout the fall to incrementally flood each slight rise in elevation, the birds can take advantage of the different food that has been produced at each of those levels. A maximum fall level is usually reached by late November. However, water level management at Odessa is not always that simple… Flooding on the Mississippi or Iowa Rivers along with heavy localized rain events may impact the water level drastically at any time.
