The owner of a controversial upscale apartment building in Minneapolis' Uptown is illegally pumping groundwater into a nearby lagoon in the Chain of Lakes and making its ice unsafe, the city contends in a lawsuit filed this week.

The lawsuit asks Hennepin County District Court to forbid the pumping of groundwater from the lower level of the building's underground parking garage into the city's sewer, which enters the lagoon. The city also asked for a penalty of $1,000 per day for alleged violation of its storm drain ordinance and for other unspecified damages.

The 56-unit apartment building opened two years ago at 1800 W. Lake St., a location that some residents regard as the western gateway to Uptown. The proposal stirred debate in 2009 over the appropriate height for buildings near Lakes Calhoun and Isles under a land use plan adopted in 2008 after construction of a taller building across the street.

Developer Daniel Oberpriller said development firm Lake and Knox LLC is trying to figure out the right thing to do, but referred further comment on the lawsuit to the firm's attorney, who could not be reached. The Minneapolis Park and Recreation Board has also discussed its legal options.

Lake and Knox LLC obtained temporary state and city permits that allowed it to pump enough water to build the building's foundation several feet below the surrounding water table, according to the city lawsuit. But its application to the state said the temporary dewatering would end after 90 days, and its city permit for discharging the water into the sewer was timed for the same period in 2011.

The city alleges that pumping to drain groundwater from the completed apartment building has continued at a rate of at least 240,000 gallons per day. That's impairing the lagoon, the city alleges, by causing thin ice and open water that imperils cross-country skiers and other lake users, while marring the scenic view.

The city also alleges that the pumping uses sewer capacity needed for rain and snowmelt, and interferes with the operation and maintenance of a city grit chamber that's designed to reduce sediment flowing into the lagoon.

"We are really frustrated by this," said Nancy Johnston, who formerly chaired the zoning committee of the East Calhoun neighborhood. "It's going to cost these developers a lot of money."

Ironically, the building's profile was lowered, pushing its garages deeper, in order to accommodate neighborhood objections. One sign of the intensity of the debate was that four adjoining neighborhoods took the unprecedented step of jointly appealing to the City Council the Planning Commission's approval of variances and other approvals the project needed. That appeal failed.

The rent for a one-bedroom apartment in the building ranges from $1,500 to $1,800 monthly, and a two-bedroom unit costs from $2,200 to $2,900 monthly. The building boasts such amenities as a fitness center, a business center and a pet care service. The same developer recently brought plans to neighborhoods for a smaller condo building one block east on Lake Street, Johnston said.

The continued outflow from the sewer was discovered by organizers of the City of Lakes Loppet, when people associated with that ski race noticed that lagoon ice was soft even in a January cold snap and inquired at City Hall, according to John Munger, executive director of the Loppet Foundation. He said the discharge disrupted the loppet route last winter.

Steve Brandt • 612-673-4438