St. Paul city officials knew of erosion at Lilydale Regional Park but did not understand the landslide danger before a landslide killed two fourth-grade students visiting the park on a field trip in May.
The investigation uncovered a 2012 email from a parks employee who had been alarmed at what he called a "high risk" of a landslide in the area.
But the city was concerned at that point about the environmental impact of soil erosion and didn't know it posed a safety threat to park visitors, said Hamline University Law School Dean Donald Lewis, who led the inquiry. His law firm handled one of the investigations.
"We have concluded that the city did not know that the soil erosion posed a threat to visitors at the fossil ground," Lewis said as officials released their findings Thursday.
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• Why Lilydale is a good place for fossils
While the deaths of the two children, Mohammed Fofana and Haysem Sani, were tragic, the city could not have predicted the slide, St. Paul Mayor Chris Coleman told reporters this morning as the city released the findings.
In the aftermath of the tragedy, Coleman said he faced some difficult questions.
"What we knew, when we knew it, what could have been preventable, was this an accident that we should have been able to predict, was this a tragedy that we should have been able to predict?
"Those were all questions that I asked myself," he said, "that I asked my staff at the very beginning of this, and that I needed answers to."
To obtain answers, Coleman commissioned two investigations that will cost the city up to $180,000.
An engineering report also released today warned that groundwater played a key role in the May landslide and that all bluff areas like Lilydale hold similar risks. Lilydale's fossil areas are historically vulnerable to landslides and would remain so, engineers said.
"It's the nature of the bluff line," said Ryan Benson, an engineer with Northern Technologies, which examined the cause of the landslide.
"It's the nature of the geology of the site, the natural weathering that is occurring out there that these slopes are going to continue to go through this weathering, erosional process as they try to lay back to their natural angle of repose," Benson said, adding it's "very difficult to predict when, if, where the next slide may occur."
The second report, conducted by the Minneapolis law firm of Nilan Johnson Lewis, concluded that city personnel knew the bluffs were eroding. The investigation also revealed that those employees were aware of a similar landslide that took place in the park two years ago, also in May -- a mere 50 yards from the one this year, Lewis said.
"But we concluded that the city's knowledge and concern was focused on the environmental impact of soil erosion, and not any safety risk posed by a sudden slope failure," he said.
Those environmenal concerns inlcuded the effect of erosion on trails, a nearby lake and the park's natural beauty.
Every year, St. Paul provides hundreds of permits to hunt fossils in Lilydale Regional Park, many of them for school groups. But Lewis said it appears the city never considered what would have happened if fossil hunters had been in the area at the time of the 2011 landslide, as they were when a section of the bluff gave way on May 22 this year.
"However, what may seem clear now, was not so clear before the May 22 incident," he said. "Our investigation suggested that city employees may not have fully appreciated or understood the meaning of what they were observing in the park."
Lewis said St. Paul is responsible for some 200 parks and recreations and that it's understandable that the city didn't "connect the dots" at Lilydale following the 2011 landslide.
John Goetz, an attorney who represents the family of Mohammed Fofana, one of the two students killed in the landslide, disagreed.
The facts presented in the report show the city should have anticipated the potential for danger, said Goetz, who also represents Devin Meldahl, who was badly injured.
"Knowing of a terrible slide that would have killed anybody in the area had there been people there two years before, they should have closed the area down at that time of year, at least for kids," Goetz said. "School-age kids, elementary school kids, should not be subjected to the kind of hazards that these poor kids were."
Lilydale Park permits and access will remain closed, Coleman said, although he hoped it would be considered safe to reopen the area someday. He didn't know when.
"Natural areas have inherent risk. That's part of the nature of them, that's part of the charm of them, that's part of the inherent beauty of them," said Coleman, who lives near the park. "But that doesn't mean that we can't learn from others in other places how we might be better able to go forward as we try to reopen Lilydale Park to visitors and school groups in particular."
Coleman says it's impossible to make a nature preserve like Lilydale or the rest of the Mississippi River bluffs 100 percent safe.
"We can put up a sign. We can put up a fence. We can put up a gate," he said. "But we can't keep people from getting back into 17 miles of wild area along the bluffs of the river in the city of St. Paul. The best thing that we can do is to arm people with knowledge."
St. Paul is working with the National Parks Service to determine the best way to make the park as safe as possible.
Read the full report. The executive summary is below: