Millions of gallons of water would wash into Clearwater Creek, dropping Bald Eagle Lake by 5 or 6 feet, if a small century-old dam crumbles in Hugo.
That's the most catastrophic scenario but not an entirely far-fetched one, said City Engineer Jay Kennedy, who has found more evidence that the deteriorating outlet at 129th Street North needs urgent attention. Rust has eaten through some of the five metal culverts and a small sinkhole appeared on the road above in May, he said.
"I would be concerned that some properties would be flooded downstream," Kennedy said last week. The city doesn't appear to own the dam, he said, but dispatched crews to repair the sinkhole "just out of sheer protection of the public."
The problem isn't a new one, but is pesky nonetheless because the dam provides an outlet for high water on 1,047-acre Bald Eagle Lake, a popular fishing and boating lake. Much more water-abundant than its close neighbor, diminishing White Bear Lake, its high levels this year have accelerated public concern over the dam's poor condition.
The outlet, which also provides a bridge over the creek, funnels water much as a spillway would function at a dam. The outlet stands 8 feet tall and spans 28 feet on a natural seam in the landscape that leads to the creek.
"It certainly caught our attention this spring, when we had a lot more flow through that outlet, that it needed to be replaced very soon," Kennedy said. "There's a greater sense of urgency."
The Minnesota Department of Transportation will pay half of the $500,000 cost to replace the dam, but a nagging mystery about who built it has left reconstruction in limbo while Kennedy and others search for the remaining money.
Documents suggest that St. Paul built the dam in about 1900 to channel water to nearby Otter Lake, an early source of the city's drinking water. Although Hugo as an incorporated city didn't exist then, Kennedy said, city leaders want a solution and have been working to bring various jurisdictions together to determine ownership.
"We want to make sure it gets rebuilt," he said.
The outlet falls within Hugo's city boundary, but most of the lake it serves lies in Ramsey County, with portions reaching into Washington and Anoka counties. The lake also borders Lino Lakes and White Bear Township.
Kennedy met with St. Paul Regional Water Services, which he said found documentation that ownership of the small dam had been transferred to the Minnesota Department of Conservation years ago. That agency, now the Minnesota Department of Natural Resources, is searching its records also.
Meanwhile, Hugo residents continue to drive over the outlet to get to their houses on the north end of the lake. The high water at Bald Eagle Lake is an interesting contrast to White Bear Lake, where low water has left docks stranded and boaters fuming.
"With all this rain that's the most water I've seen come through this structure in several years," Kennedy said.