Giant concrete piers, standing like the ghosts of early industry, for years inhabited the St. Croix River where a new four-lane bridge now links Minnesota and Wisconsin. To conservationists, those 24 unused piers represented blight on a free-flowing river.

Now they're gone, removed in a great sweep of environmental improvements made possible by Minnesota's largest bridge project.

"They were huge structures, like big silos in the river," said Randy Ferrin, who belongs to a river advocacy coalition known as the St. Croix Basin Team. "Getting rid of them and that eyesore was a highlight of this project."

It's part of an effort by both states to define a post-bridge environmental future for the federally protected river, funded as part of the $646 million multiyear project.

While the bridge captured the headlines, conservationists and local governments have used a $42 million budget for "mitigations," as they're known in the public policy world, to fund parks, study phosphorus runoff, preserve land along the river bluffs from development, and even write a "spill response plan" should mass pollution of the St. Croix occur.

Removing those cumbersome piers, at a cost of $1.1 million, was one of the most noticeable improvements funded with bridge money. Tons of sand inside the piers was spread on the river bottom to encourage fish habitat and aquatic health.

Other visible changes will include restoration of the now-retired 1931 Stillwater Lift Bridge to its original "federal green" color, along with reproductions of its original lamps, and the completion in 2019 of a 5-mile loop trail that will cross over the new and old bridges.

These projects — and dozens of others now mostly completed on both sides of the river — cover everything from the St. Croix's water quality to stormwater and wastewater monitoring, historical preservation, recreational enhancements and land use updates.

Finding sound solutions

The one major bridge-funded project that won't make the May 2018 deadline for completion for bridge spending is a countywide review of its zoning laws. Ellen Denzer, St. Croix County's development director, said that project, intended to manage population growth, could last a year beyond the deadline.

"We've tried to consider all these different protected resources and find sound solutions," said Todd Clarkowski, the Minnesota Department of Transportation engineer who coordinated the bridge project.

Clarkowski was involved in the 28-member stakeholder group that forged compromises for the long-debated bridge proposal in the early 2000s.

Many of the ideas for protecting natural resources, he said, came from a consensus among stakeholders that building a bridge over the St. Croix called for an environmental "balance." More money was invested in St. Croix-related improvements than for any other Minnesota bridge project, Clarkowski said.

Engineers and planners on both sides of the river said their environmental work carries far-reaching benefits for water quality, tourism and other major issues confronting the St. Croix. It also will increase public awareness of pollution, erosion and other threats, they said.

Many of the environmental improvements, including land acquisitions, wouldn't have happened if the bridge hadn't been built, Denzer said.

Ferrin agreed. "A lot of great stuff was done with the mitigation money," he said.

Waiting for growth

Much of the work still being done is on the Wisconsin side of the river, where St. Croix County is preparing for more residents and businesses that the bridge could bring.

County planners and supervisors in St. Joseph Township, where motorists cross the bridge into Wisconsin, have reviewed land use, stormwater runoff, wastewater treatment, trail potential and preservation of green spaces.

Similar work is being done in the Wisconsin cities of Somerset and New Richmond along the Hwy. 64 corridor.

"They've been working extremely hard to prepare the county. It's really been impressive to see," said Dan Baumann, a Wisconsin Department of Natural Resources regional director who coordinates the improvements.

The ultimate mission, Baumann said, is to adopt clean water practices to protect the St. Croix River and two main tributaries, the Willow and Apple rivers.

"The only way we get environmental improvement or restoration is through collaboration," he said.

One of the participants is Tom Spaniol, who chairs the St. Joseph town board. St. Joseph updated its comprehensive plan a year ago, commissioned a natural resources inventory, created a trail plan and studied wastewater.

The town is now positioned to handle any growth that might come, Spaniol said, but so far there's very little of it.

"A lot of the property owners were waiting for the bridge to open because they thought there was the pent-up demand to buy land, but there was no land rush," he said.

St. Joseph has 285 undeveloped lots, but because it has a 3-acre minimum for houses, many people can't afford to pay $140,000 for land to build on, he said. Only two developers inquired about buying 40-acre parcels, and most of the farming land near the bridge isn't for sale.

"It's going to be slow, controlled growth," Spaniol said of potential development in St. Joseph.

Denzer said county officials have used bridge money to purchase land in four places to block future development. Seven acres were purchased near Houlton Elementary School for a trailhead for the loop trail. Fifty-two acres on the river bluff were purchased in 2015, and an adjacent 114 acres were acquired later. Another 14-acre plot of land is now in county hands to ensure habitat and water protection.

"This is a real opportunity to look at things in concert," Denzer said. "Our intent is to do a much more thorough job with better impact in the long term."

Kevin Giles • 651-925-5037