Citing numerous concerns, the city of St. Paul has asked Canadian Pacific Railway for more detailed answers about how its plans to expand a rail switching yard along the Mississippi River will affect the environment.

After weeks of reviewing the railroad's plans and taking comments from government agencies, advocacy groups and the public, the city announced Friday that it is requiring a full environmental impact statement (EIS) before approving a permit.

The decision puts the project on hold for the moment. The timeline for developing the EIS varies greatly, city planner Josh Williams said. The first step will be determining the questions about the project that need answering, a process that will be led by the city and include at least one public meeting.

Ed Greenberg, spokesman for Canadian Pacific, said the railroad was disappointed in the decision. Canadian Pacific, he added, has done its due diligence to address all environmental components associated with the project, which should reduce train congestion, locomotive idling and noise from switching operations.

Concerns for wetlands

The proposed expansion of what is known as the Dunn Yard — which entails adding six new tracks, lengthening them from 7,000 to 10,000 feet to accommodate longer trains and filling in more than 6 acres of wetlands along Pig's Eye Lake — "has the potential for significant environmental effects," the city said in a ruling signed by Kit Hadley, St. Paul's interim planning and economic development director.

The city is most concerned that the expansion will essentially fill in the wetlands around Pig's Eye Lake, which is fed by an inlet from the river. Wetlands are an important wildlife habitat that filter pollution and sediment and aid in flood control. Without the wetland buffer, both the lake and river could be affected, along with the river's flood plain.

The plan also would add an 880-foot retaining wall made of steel sheeting, ranging in height from 5½ to nearly 11 feet. Pilings to support the wall would be 23 to 43 feet deep. Canadian Pacific has said that groundwater could flow through seams in the wall and weep holes added to the pilings, but the city wants specific details on how effective those measures would be.

The railroad is required by law to replace the wetland at a 2-1 acreage ratio. It's proposing to buy wetland banking credits for its mitigation, documents show, rather than create or restore wetlands in the area.

In its comments, the Ramsey-Washington Metro Watershed District "has significant concerns with the major wetland and flood plain fill being requested."

Potential habitat impact

The city also said it needs more answers on the safety risks of having more and longer Canadian Pacific trains coming through the Dunn Yard, where there is no spill containment system.

Because the St. Paul expansion would reroute traffic from other parts of the railroad's network, the city says, there is "a potential for increased risks from hazardous materials, including potential impacts to public safety and potential impacts on water quality and wildlife and wildlife habitat."

The railroad has characterized its expansion plan as having no impact on the amount of rail traffic coming through the yard, nor the types of materials carried by the trains.

By making its rail operations more efficient, Canadian Pacific asserts, it will actually reduce the risk of incidents involving hazardous waste.

The railroad's plan conflicts with St. Paul's Great River Passage master plan, an effort to develop 17 miles of Mississippi riverfront that's been years in the making.

Pig's Eye, the largest lake in St. Paul, now is almost inaccessible to the public except by boat. The city envisions linked trails in the regional park surrounding the lake, as well as fishing and paddling access.

The railroad's plan "almost certainly will result in both large cost increases and technical challenges" to achieving that vision, according to the state Department of Natural Resources.

In response, Canadian Pacific points out that some of the city's plan included building trails on the railroad's property. It acknowledges that the park plan isn't compatible with the yard expansion, but says it would be willing to help find alternative access points to the park.

The park provides habitat for Blanding's turtles, a threatened species in the state, about a half-mile from the project area. It's also home to the Pig's Eye Island Heron Rookery Scientific and Natural Area, one of the largest urban heron and egret refuges in the Upper Midwest and site of several eagle's nests.

According to the railroad, the project will not directly affect the hatchery. It agreed to a DNR request to avoid loud construction during nesting periods.

Jim Anderson • 651-925-5039 Twitter: @StribJAnderson