Digest>Archives> January 2001

Erosion Control Projects Set for Two Apostle Islands’ Lighthouses

By Jim Merkel

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Outer Island Lighthouse, Wisconsin.
Photo by: Karen Harshman

More than lovers of flags were upset when the flagpole at the Raspberry Island Lighthouse was taken down and moved in 1994.

The relocation was a clear sign of the steady erosion of the bluff in front of the venerable old light station on the western side of the Apostle Islands National Lakeshore in Lake Superior. So fast is the pace of erosion that one National Lakeshore staff member worries the lighthouse itself could lose a part of its resources within a decade. He also said another Apostle Islands lighthouse, at Outer Island, may be in jeopardy within two decades, as erosion eats away at a bluff near that lighthouse.

Though the steady erosion at the steep red clay banks next to both lights seems grim, there is hope for lighthouse enthusiasts; Congress has authorized expenditures of nearly $2 million for projects to stabilize the banks at the two light stations this year and next year.

This year, the government hopes to do bank stabilization at the Raspberry Island Lighthouse, which was first lit in 1863. Next year, it will turn its attention to the light at Outer Island, which went into operation in 1874. The two are among six historic light stations in the Apostle Islands National Lakeshore, the largest collection of light stations in the National Park Service. During the summer, cruise boats regularly visit the Raspberry Island Lighthouse. There are fewer visits to the Outer Island Lighthouse, which is at the northeast corner of the Apostle Islands. The only time scheduled cruises make stops there is during the Apostle Islands Lighthouse Celebration each September.

The erosion control projects will come none too soon for the light stations, which were placed on the Lighthouse Digest “Doomsday List” of endangered lighthouses in 2000. The corner of the fog signal building at Raspberry is about 25 to 30 feet from the edge, and is losing ground at the rate of more than four inches a year. Portions of the fog signal building and lighthouse at Outer Island are less than 50 feet from the edge. At Outer, the erosion rate in front of the signal house from 1978 to 1991 was between .98 and 1.18 feet a year.

“If nothing is done, we’re looking at a significant loss of the resource at Raspberry Island within 10 years, and at Outer Island in 10 to 20 years,” said Bob Mackreth, historian at the Apostle Islands National Lakeshore. “So now’s the time to do it.”

The Fiscal Year 2001 Interior Appropriations Conference Report signed by President Bill Clinton included allocations of $1.36 million for repair of erosion at the Raspberry Island Lighthouse and $600,000 at the Outer Island Lighthouse. The legislation was promoted by U.S. Sen. Russ Feingold, a Democrat from Wisconsin. Feingold visited the Outer Island Lighthouse in July 2000 to assess the needs at Outer Island.

“If we are to be true stewards of America’s public lands, we need to be willing to make necessary financial investments and management improvements when they are warranted,” Feingold said in a statement released in October. “My family, like so many other Wisconsinites, vacations regularly in this truly beautiful place. I am delighted that Apostle Islands National Lakeshore will receive the attention that it deserves in order for it to be available for many generations to come.”

Another strong supporter of the legislation was the Congressman from the area, Democrat Dave Obey. He visited the Raspberry Island Lighthouse in the summer of 2000, and promised to push for funding for erosion control.

In both cases, efforts will be made to prevent erosion at the bottom and the top of the clay banks.

“We’ve got the force of Lake Superior hitting at the base of the cliff and causing erosion at the base,” Mackreth said. Meanwhile, erosion at the top causes big chunks to fall off. Erosion at Raspberry Island is occurring at the rate of .36 feet per year. Based on that calculation, the shore moved back 42 feet between 1882 and 1989.

“What happens is there’ll be several years where nothing happens, and then one year a big chunk several feet (wide) will break off and fall down,” Mackreth said. In the 1990s, in addition to moving the flagpole, a rope meant to keep visitors away from the edge has been moved back.

There are unstable clay banks throughout the Apostle Islands archipelago, causing the shoreline to recede, Mackreth said.

On the other side, at the light station on Long Island, at the south end of the archipelago, something different is happening. The island - basically a sand spit extending northwest from the shoreline - is moving northward, away from the lighthouse. The original 1858 lighthouse, which is now in ruins, is the best part of a quarter-mile inland, Mackreth said. That lighthouse was replaced by another one in 1895.

At Raspberry Island, plans are to put a revetment (sea wall) at the bottom, high enough to resist waves of a Lake Superior winter storm. At the top, there will be a drainage trench. Water will run off through a drainage system, to the lake, thus reducing erosion from the top. Also, the slope will be regraded and covered with vegetation to further reduce the erosion.

Jim Nepstad, management assistant at the Apostle Islands National Lakeshore, said visitors to Raspberry Island may experience some inconvenience. “The public should expect a little bit of disruption for the upcoming summer,” he said.

But Nepstad added that the Raspberry Island Lighthouse will be accessible to the public nearly every day this summer. “Only a very small number of closure days are expected,” he said.

At Outer Island, there are similar plans. There will be a trench on top, to redirect the water flow. Also, there are plans to regrade the slope and put vegetation over it. At the bottom, there will be a protective wall. In addition, there will be a stone breakwater below the surface of the lake.

There will not be a submerged breakwater at Raspberry. “This is an area that a lot of boaters come to and it’s relatively deep water. You can get in very close,” Mackreth said. There are fewer boaters at Outer Island, and the traffic is fairly shallow anyway, he said. “This does not present a navigational hazard here that it would if we were to do something like that at Raspberry Island,” he said.

This story appeared in the January 2001 edition of Lighthouse Digest Magazine. The print edition contains more stories than our internet edition, and each story generally contains more photographs - often many more - in the print edition. For subscription information about the print edition, click here.

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