Researchers taking a close look at the Grafton wetland

By DON BEHM
of the Journal Sentinel staff

Last Updated: July 8, 2001

Town of Grafton - The summer assignment in Ozaukee County for three researchers: Wade through the dense muck of the largely hidden Ulao Swamp and uncover for the first time the diversity of plants growing in the 490-acre wetland south of Port Washington.

Ulao Swamp Photo/Peter Zuzga Research assistant Kathi Weyker of Belgium slogs through the Ulao Swamp to inventory plants and trees and collect samples in the Town of Grafton. Photo/Peter Zuzga Field biologist Jill Hewitt uses a densiometer to measure the amount of sunlight that filters through the canopy of the Ulao Swamp in the Town of Grafton. Hewitt and two research assistants are spending the summer inventorying plants and trees in the swamp. Quotable All right. This is muck. It feels good. - Jill Hewitt, biologist

This two-mile-long swamp at the headwaters of Ulao Creek is little known to even its neighbors. A fringe of trees and shrubs hides the swamp from the view of local residents or passers-by on Port Washington Road and Highway C. It is just south of where the massive Port Vincent housing development is planned.

A partnership of local landowners and county and state agencies hired the researchers to complete a plant inventory in the swamp as part of a restoration project for the Ulao Creek watershed in eastern Ozaukee County. The swamp protects the headwaters of the stream.

Entering the edge of the swamp west of Stonecroft Drive recently, Jill Hewitt and two research assistants push through grasses standing six feet tall at the end of June. Dogwood towers above the grass.

Hewitt takes a compass reading and sets out. Breaking out of the dogwood, she steps into shallow water.

"All right. This is muck," Hewitt calls out, as if she's just returned home from a long absence. "It feels good."

Frail, green fronds of duckweed, the world's smallest flowering plant, float on the surface.

While the deep mud is familiar to the trio of biologists, it is not an ally in their work.

The mire hides fallen trees that become stumbling blocks slowing progress through the swamp. When legs sink knee-deep, or more, into the muck, it becomes difficult to walk. The mud pulls on clothes and boots.

"It takes us 45 minutes to go 100 meters in some of this stuff," Hewitt says.

At 10 a.m. on a recent workday, sweat cascades off the forehead and nose of assistant David Voigt as he struggles to free himself from the mud's grasp. Voigt's strategy is to lean in the direction of travel so that he lies nearly parallel to the surface as he pulls out the stuck leg.

The free limb advances one step, and Voigt repeats the process until he reaches a shallow area.

Voigt, a native of Brookfield, does not admit to second thoughts about his selection of what has to be the most uncommon summer job in the region. Fieldwork could become routine for him. He is pursuing an environmental science degree at Southwest State University in Marshall, Minn.

Their first research stop of the day is 20 meters west and 60 meters south of their entry point. A second destination was marked 100 meters east of the first. A third was marked 100 meters east of the second, and a fourth at the same distance from No. 3, as the team established a line of study across the swamp.

Where the swamp narrows, only three research sites are marked on such east-west transects. Wider portions of the wetland accommodate as many as 12 points.

At each site, Voigt pushes a plastic pipe into the muck to mark the spot. Field biologists in the future will locate the pipes to determine whether there has been a change in the plant community living there.

On this day, the first pipe is located within cattails in the shadow of an American elm and a silver maple-red maple hybrid.

"No poison sumac," Hewitt says after scanning the site.

As Voigt holds one end of a tape measure at the pole, Hewitt marches five meters east and ties a red ribbon around a clump of cattails. She places a square, wooden frame atop the muck's surface here and drops out of sight within the tall, narrow leaves of the cattails.

"Oooh. This is cool," Hewitt says, in response to finding several Boneset, a native flower.

'Nature is my boss'

"Clearweed. Water arum. Sedge. Water hemlock. Duckweed. There's a lot of goodies in this one," Hewitt says.

After picking through the vegetation, Hewitt raises a special instrument, known as a densiometer, to measure the amount of light streaming through the tree canopy.

The process is repeated five meters west of the post, as red-winged blackbirds trill unseen from nearby trees.

Weyker, an undergraduate in environmental science and biology at the University of Wisconsin-Green Bay, seeks shade as Hewitt inspects more plants.

"I love this," Weyker says, extolling the benefits of an outdoors job in summer. "Nature is my boss." The boss is kind on this day, providing occasional clouds to block the sun.

Hewitt removes a single Canada bluejoint grass that will be preserved in a collection of plants from the swamp. She shows her assistants how to identify this native species, the grass most frequently associated with sedges in certain types of wetlands.

"Oh, this is the stuff you can whistle with," Weyker says. Grasping one of the plant's slender leaves between her thumbs, Weyker's attempt at a whistle sounds more like a duck call.

Before moving on to the next research site, Hewitt walks a circle around the post and measures all trees greater than 2.5 centimeters in diameter.

High water threatens trees

One reason might be that water levels are higher than in the past. The likely source of the water is residential and other development around the outside of the swamp, according to Hewitt.

"Today, water flows off lawns and roads and fields and into the swamp," she says. "Some of that water should be diverted to maintain the swamp forest."

Hewitt will recommend that the Ulao Creek Partnership consider such a step in future land use planning.

"Otherwise, we will be left with an open marsh or shrub carr wetland with few trees," she says.

Maples and green ash, particularly, are vulnerable to higher water levels in the swamp, according to Hewitt. Black ash and American elm appear to be holding their own.

Nearly 11/2 feet of water now stands above the muck north of where Ulao Parkway crosses the swamp, Hewitt says. Few trees remain there except on the eastern edge. Cattails are filling in the open spaces.

The widest portion of the swamp, which includes a leg extending toward the intersection of Lake Shore Road and Ulao Parkway, is now the wettest section. Water stands waist-high there, Hewitt says. It has been transformed into an open cattail marsh with little plant diversity.

The white cedar and other conifers that used to dominate the swamp prior to settlement of the region are largely absent. They have been replaced with hardwood trees and shrubs. Now the maples and ash and other hardwoods are threatened by the latest human disturbance, rising water levels.

At this point in the summer-long study, Hewitt and her assistants have collected and identified 150 plant species. There could be as many as 400 hidden inside the long, narrow swamp, she said.

Blue flag iris and joe-pye weed are among them.

Atop joe-pye stems are a dozen or more pink or purple flower discs. The iris splash light to deep blue petals on the swamp floor.

For Hewitt, they are the beauties within this beast of a workplace.