Shoreline takes beating

• Erosion

Julie buntjer/Daily Globe Soil erosion can be found along Sailboard Beach following the high lake level of a couple weeks ago.

Talk about it

WORTHINGTON — Water levels on Lake Okabena have dropped more than a foot since a deluge of rain fell on the region nearly two weeks ago, but the damage it left behind will take much longer to fade into the memory of some property owners with lakeshore lots.

Among battered docks and signs of slumping shoreline, perhaps the most visible destruction caused by the five-plus inches of rain occurred on a parcel of property along South Shore Drive. There, nearly the entire width of a single lot saw significant erosion — so much so that boaters passing by can see a sudden drop-off that reveals a layer of sod and black dirt atop several feet of clay.

Typically, shoreline erosion happens over time. As the lake rises and falls, freezes and thaws, it puts pressure on the shoreline. Residents who don’t take steps to stabilize their lakeshore — whether they keep the natural vegetation in place or maintain riprap or a retaining wall — will, over time, begin to see their shoreline fade into the lake.

“The more trees — woody vegetation — you leave on the shoreline, the better it’s going to be,” said Dan Livdahl, Okabena-Ocheda Watershed District Administrator, during a lake tour Monday afternoon. “A lot of people have cleared the trees to improve their view of the lake.”

Good examples of shoreline stabilization can be seen all around Lake Okabena, from the clusters of trees that keep the soil in place along the northwest shore near Vogt Park to the concrete slabs that have protected the shoreline along Slater Park for decades. Both of those examples are on city-owned property.

There are private property owners with success stories as well. One parcel — located next door to the property that suffered the most significant damage — features large rocks strategically placed along the slopes, surrounded by a variety of native plant and grass species.

The native plants have deep root structures to help hold the soil in place, said Livdahl. Good options for landowners who want to incorporate native plants into their lake lot include everything from big bluestem and Indian grass to switchgrass and prairie flowers, he added.

Ordinance enforcement

Though a section of Worthington’s city code details regulations for alterations of vegetation and topography, rarely if ever does the code get enforced.

The code states that “alterations of vegetation and topography will be regulated to prevent erosion into public waters, fix nutrients, preserve shoreland aesthetics, preserve historic values, prevent bank slumping and protect fish and wildlife habitat.”

It goes on to detail that intensive vegetation clearing within the shore and bluff impact zones, and on steep slopes, is not allowed.

Despite the written ordinance, Livdahl said the city doesn’t go after offenders, and the watershed district doesn’t have a system in place to prosecute people.

Natural shorelines

Wayne Smith, Nobles County Environmental Officer, also serves as the county’s shoreland administrator. He has jurisdiction over all of the lakes in the county, with the exception of Lake Okabena in Worthington.

“We’re very fortunate in Nobles County that all the lakes (except Lake Okabena) are natural resource lakes,” said Smith. “With fewer homes on the lakes, landowners are more content to leave nature undisturbed.”

Smith said most property owners don’t realize they should leave trees and vegetation in place along the shoreline. Rather, most think they need to have the well-manicured lot with lush grass growing right up against the rocky shores.

In recent years, the city has worked to protect the shoreline of Sailboard Beach by installing riprap. Even with that work, the high water levels of a couple weeks ago caused some noticeable damage. In a couple of areas visible by boat, rocks have either sunk or disappeared to reveal a layer of eroded soil.

Livdahl said the damage is heading ever more closely to the bike path. Trees once surrounded by grass are now so close to the water’s edge that portions of their root system have been exposed.

“That’s the reason for the city’s riprap project there,” he added.

State-wide issue

Shoreline erosion isn’t just taking place locally, but can be found on lakes all across the state, Livdahl said. And while Worthington’s city code details what lakeshore landowners can and can’t do regarding stabilization efforts, the responsibility ultimately falls on the property owner.

The Okabena-Ocheda Watershed District has resources available to landowners who want to implement lakeshore stabilization practices, and cost-share funding may be available through the Soil and Water Conservation District’s Ag Best Management Practices (BMP) program or other shoreland stabilization programs spearheaded by the Department of Natural Resources and the Board of Water and Soil Resources.

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