Zoo Interchange Plan May Help Butterfly Habitat on County Grounds

Parks and open space advocates have minced no words about their dislike of the proposed siting of three stormwater detention basins outside the bounds of land owned, controlled or being acquired by the state Department of Transportation for the Zoo Interchange project.

Wauwatosa Patch reported Friday on concerns over loss of public parkland to two of the three basins the DOT has proposed.

But for one Wauwatosa land and wildlife steward, there is a silver lining in the DOT’s new Reduced Impact Plan, and also some possibilities that could make the plan an even bigger boon to her favorite place.

Barb Agnew, Wauwatosa resident and owner of Barb and Dick’s Wildflower floral shop at 12326 Watertown Plank Road, founded the Friends of the Monarch Trail several years ago to protect and promote a rare spectacle of nature. Every September, monarch butterflies on their annual migration to Mexico stop off at certain groves of trees on the County Grounds to roost for the night, sometimes in thousands at a time.

Agnew has worked tirelessly for three years with Milwaukee County and the University of Wisconsin-Milwaukee Real Estate Foundation to set up a monarch habitat protection zone prior to the sale of the land to UWM for its Innovation Park engineering research center.

She has also negotiated with the DOT and acted as an ad hoc adviser on the Zoo Interchange project to see to it that highway construction plans take into account the need to preserve the butterfly roost trees and adjacent wildflower meadows.

“So far, we’ve been successful in establishing the habitat zone as a no-build site with UWM,” Agnew said, “but of course we’ve been waiting to see what this highway plan would look like.

“It’s not all good, but I’d say that for the Monarch Trail there’s more good than bad, and a number of ways to make it even better.”

The habitat area surrounds the Eschweiler buildings southeast of the junction of Highway 45 and Swan Boulevard.

Initially, Agnew was contending with plans that would encroach on the habitat zone and a grove of oak trees with a new northbound ramp to Swan lying further to the east than the existing one.

But the revised plan does away with access to Swan east of the freeway altogether and instead sends both lanes across Highway 45 via a new bridge.

That change is necessary because the DOT abandoned plans for a large interchange to access Wisconsin Avenue and Blue Mound Road as too costly.

“Interests at the Medical Center and the Research Park had wanted direct access to the freeway,” said Tim Anheuser of Forward 45, a group of three engineering firms on contract to advise the DOT. “We said, ‘If we can’t give them access here, we’ll give them a free-flow interchange at Watertown Plank.'”

“Free-flow” refers to an intersection at which no traffic going in any direction or changing direction has to stop. The existing intersection at Watertown Plank, including the ramp to northbound Swan, has traffic signals that could require a stop in any direction getting on or off the freeway.

The free-flow concept, however, requires a full cloverleaf design that occupies more space. The northeast cloverleaf ramp would edge over the DOT easement, and the associated detention basin would sit mostly outside of it on land that ultimately would be included in the UWM plan, but for now is also part of the route of the Monarch Trail.

The Sierra Club and others have decried the impact of the freeway project on the trail, but Agnew said the new plan actually has advantages for her program, increasing the space available to the most critical butterfly habitat zone.

“We gain ground, but we hit a wall,” Agnew said. “The Swan roadway would be elevated to go over the freeway, but the approach to it that they show is not a bridge, it is a berm that would be a barrier to both people and wildlife wanting to move between the natural areas north and south of Swan.”

Nevertheless, Agnew sees a solution to that problem that would in fact be an overall enhancement to the many recreational interests in the area.

The ground-level Swan Boulevard “is a hazard now to cross, and this plan would put up a barrier,” Agnew said. “But it also offers the opportunity to create a tunnel, or passageway, under the road that would be a safe and natural connection between the forestry property up here (to the north) and the Monarch Trail.

“In fact, this would be a conduit connecting the whole network of trails and routes (on the Grounds) that are now interrupted or made difficult by dealing with Swan Boulevard," she added. "This would create the connection everyone has been talking about.”

Agnew forwarded a proposal and photos of such underpass conduits to the DOT, which she said had shown interest.

Agnew is less pleased with the planned detention basin to the south, but she sees a simple and obvious solution to that as well.

“Just put the pond inside the cloverleaf,” she said, pointing to a map showing the circular area enclosed by the ramp as nearly the same size as the proposed pond outside it.

“There is ample room inside the footprint of the interchange to deal with the problem (of runoff),” she said. “You see this everywhere you go, detention basins inside cloverleafs and between ramps and roadways.

“It’s unusable, inaccessible space anyway, so it’s a logical use of the land.”

The DOT is also considering that plan, she said.

Agnew also said that while the south berm area, where the pond is currently proposed, is not the primary butterfly habitat on the Grounds, it is important.

“The south berm is degraded habitat in some ways,” she said, “but it is just entirely covered by whorled milkweed,” a native plant that monarchs use heavily for both feeding on nectar as adults and on the leaves of the plants as caterpillars. Monarchs lay their eggs and feed as larvae exclusively on members of the milkweed family.

“Whatever happens,” Agnew said, meaning loss of the tract to the DOT basin or later development by UWM, “I wish they could just scrape up this topsoil from here and lay it down over there. I’ve never in my life seen such a solid concentration of whorled milkweed.”