On busy Lake Minnetonka, Big Island is a sanctuary.
Every day in the summer, boats of every shape and size zip past Lake Minnetonka's Big Island or tie up at its infamous Cruiser's Cove for floating parties.
The mainland shore is lined with well-kept homes, many of them mansions.
Despite the activity, the island is a rare oasis in the metro area: 275 acres of woods and wetlands that are reverting back to their natural state thanks to partnerships between the city of Orono, the Minnehaha Creek Watershed District and Three Rivers Park District.
"It's a really nice sanctuary area where the wildlife doesn't get harassed to any large extent, and the natural processes can continue as they have for thousands of years," said John Barten, director of natural resources for Three Rivers.
The Park District owns the 62-acre Arthur Allen Wildlife Sanctuary on the island. The city of Orono owns the 56-acre Big Island Nature Park next to it. Both are working with the Watershed District to give the island's shoreline a facelift, the most recent environmental project on the island.
"The opportunity to preserve a 56-acre park in its natural state in the middle of Lake Minnetonka was a huge priority for us," said Renae Clark, project manager for the Watershed District.
Volunteers as caretakers
On a recent boat tour of the island, Gabriel Jabbour pointed to the top of a 30-foot bluff, where a nylon rope dangled from the edge with a faded plastic tent stake attached to its end. "Ten years ago there were people camping up there on a piece of ground that no longer exists," he said.
Jabbour, an area businessman, owns one of about 50 seasonal homes on the island. He was a key player in assuring that the eastern third of Big Island became the Nature Park in 2006.
Jabbour also serves as the Nature Park's volunteer custodian, organizing dozens of volunteers to remove hundreds of tons of trash from the park over the past few years. It is open for day use only, including swimming, picnicking, hiking and exploring the few remaining concrete foundations and terra cotta facing from a long-defunct amusement park. It has a public dock, but no running water or restrooms. Overnight camping, fires and motor vehicles are prohibited.
An opportunity for study
The Three Rivers Wildlife Sanctuary is closed to the public, available only to scientists with permission to conduct research. Barten said it's an excellent opportunity to preserve a high-quality natural system, one that's home for kingfishers, osprey and eagles, as well as rare plants and ferns.
"Obviously being on an island surrounded by water, there's less of an opportunity for some of the invasive plants and some of the runoff that degrades most of our other wetlands," he said. "You don't see that in the rest of the metropolitan area."
Other protections include a conservation easement on the park purchased by the Watershed District to ensure that it will never be sold and developed.
The property hosted an amusement park with a roller coaster, carousel and other rides in the early 1900s, and was a popular destination for city folks who could ride streetcars to the lake and hop steamboat ferries to the island.
In the 1920s, the land became the Big Island Veterans Camp, and for decades it offered camping and other recreation for Minnesota's war veterans.
The problem of shoreline erosion is more recent, and has developed over the past couple of decades, said Jabbour.
"It's wave action, and bigger boats on the lake," he said. "Man-made waves and God-made waves."
Clark pointed to an ocher-colored bluff along the Three Rivers sanctuary shoreline that is one of the next targets for repair. Lining its side were trees that had given way and slid down the slope.
"The waves crash up against the shoreline and undermine the steep bluffs from the bottom, so it gets dug out, falls, gets undermined again and falls again," she said.
One project completed three years ago stopped bluff erosion along 2,700 feet of the nature park's shoreline.
Another $300,000 will be invested in the next year, beginning this fall, to halt collapsing banks along the Park District's sanctuary.
To stabilize the bluffs, Clark said, landscapers need to flatten out the slopes and revegetate them.
The remedy is to build flat "benches" at the foot of the eroding cliffs that extend about 15 feet to the water's edge, she said. Landscapers first install rocks as barriers along the shoreline, or use biological blocks such as jute-covered rolls or bricks of compost. Behind the barriers they install sand or pea gravel, and plant it with willow, dogwood and other water-friendly plants and bushes.
As the flat benches fill in with vegetation, Clark said, the exposed clay bluffs are protected and eventually will break down to form a more gradual "angle of repose."
Tom Meersman • 612-673-7388