City develops around changing ecosystem

In Winona County, they found that only between five and 10 percent of the land (less that 40,000 acres) still supported intact natural communities.

The rest had fallen to the ax and plow, under the sweat of European and American immigrants who muscled out a settlers’ life.

In 1851,Winona’s population was less than two dozen, hardly enough to muster a full-fledged landscape alteration.

But by 1900 it had reached nearly 24,000, a 50-year explosion that changed the land and the course of one of the earth’s largest rivers.

Prior to settlement, ecological change occurred on a geologic scale spanning thousands of years — a direction and pace unsuited to human time line.

In 1805, U.S. explorer Zebulon Pike climbed the bluffs over the future site of Winona.

Tall grasses blanketed the prairie below.

The river’s sloughs were braided in a diverse mosaic.

Animals roamed the land that have been gone so long we can scarcely imagine they ever existed: bison, elk, black bear, pronghorn antelope, wolf.

Pike experienced a river with species that were eventually extirpated or pushed to the margins.

Amber waves of wild rice flourished.

Fishes like the blue catfish, skipjack herring, pallid sturgeon, and others plied the waters.

The pre-Winona landscape was oak savanna, a mix rarely seen today, where scattered, fire-resistant oaks are enveloped by a sea of prairie.

Aside from the site of the future city, these also occurred on the bluff tops.

Natural fires regularly scorched them, rejuvenating the grassland and keeping oaks sparse.

Oak savannas were inviting to the continent’s most native and widespread herbivore, the bison.

On south-facing bluffs, where sunlight maintains heat and dryness and a steep slope keeps big animals off, prairie remnants held on, and still do.

Because of their unique qualities, goat prairies harbor the tag-ends of a former time, like timber rattlesnakes and birds-foot violets.

On the shaded slopes, richer soils rooted oaks, maples and basswood.

These forests, as well as the bottom land silver maple, ash and elm, served the black bear, wolf, bobcat, lynx, cougar and other mammals that eventually fled humans.

Humans suppressed fire, and savannas succumbed to encroaching trees.

This expanding forest soon became a crop of the lumber industry.

The river was less amenable to alteration by humans and staved off development.

Flood plain forests, wetlands and isolated sand prairies harbored rich arrays of reptiles, amphibians, fishes, mammals, birds, insects and plants.

Pickerel frogs and redshouldered hawks, rare today, likely flourished.

The Corps

In 1824, the U.S. Army Corps of Engineers began rudimentary river engineering to accomodate steam boats.

In 1866, Congress ordered dredging a 4-foot navigation channel, removing snags, clearing overhanging trees and removing sunken vessels.

In 1872, the Corps pulled nearly 1,300 snags and cut 2,600 overhanging trees.

As shipping increased, so did commercial requests for an improved channel.

In 1878, Congress authorized a 4.5-foot channel depth.

A campaign had clearly begun to transform one of the world’s largest rivers into an aquatic highway.

The Corps began building wing dams to deflect flow into the center.

Side channels were closed to keep water in the channel.

Shoreline was rocked to prevent the river from carving its flood plain.

Before Winona saw the 20th century, the free flowing river became an engineered channel, more narrow with a shrinking flood plain.

After steamboats were edged out by railroads, navigation boosters pushed for and won a new federal project in 1907 for a 6- foot channel, intensifying channel constriction.

The Corps added more wing dams and closing dams.

By 1912, river channeling was considered a failure, but the Great Depression of the 1930s required a work project.

In response to transportation crises, Midwestern business and navigation interests pushed for and were granted a 9-foot channel, leading to construction of the federally-funded lock and dam projects between 1934 and 1940.

Each dam required clearing land for the pool.

For 5A in Winona, 10,000 acres were cleared.

Number 6 in Trempealeau — 3,300 acres.Water flooded new areas and aquatic life bloomed shortly after 1940s.

But soon, areas like Weaver bottoms near Kellogg became sandy, turbid and lifeless.

Second to the Corps’ alteration of the river, and contrary to it, was the 1924 establishment of the Upper Mississippi River National Wildlife and Fish Refuge.

It occupies 261 miles from Wabasha, Minn., to Rock Island, Ill.

Fifty of these miles are managed by the Winona District.

It was established as an important migration corridor used annually by millions of waterfowl, songbirds and raptors.

Today, 3.5 million people visit the refuge each year, more than Yellowstone Park in Wyoming.

When you look at the river today, it is hard to imagine being able to wade across it.

Trees filled the bottoms on hundreds of islands, dispersing flowing water into innumerable side channels and wetlands.

Hundreds of sandbars broke the surface in the main channel.

These features made the river a natural aquatic wildlife haven, and an impediment to cheap, reliable river transportation.

So far, each side is holding its ground in a struggle for ground near the sandy island that today is called Winona.