The views from the observation deck of the Witch's Hat, a historic water tower in Minneapolis' Prospect Park neighborhood, are as precious as they are rare.

The 110-foot tower offers a panoramic view of the Twin Cities, but visitors are able to climb up to the deck only once a year, during a school fundraiser near Memorial Day.

Now a neighborhood group is alleging that a planned 14-story condominium along University Avenue will ruin that view. Last week, it sued the developers of the project in an attempt to stop construction.

The lawsuit, filed by the nonprofit Friends of Tower Hill Park against Vermilion Development and three property owners, argues that the redevelopment would violate the Minnesota Environmental Rights Act by blocking the observation deck views of downtown St. Paul, including the State Capitol and the Cathedral of St. Paul.

"If you put another tall structure next to it, you obscure and obliterate views out from the tower, but you also detract, in a substantive way, from what this tower right now means as an iconic landmark," said Gayla Lindt, a lecturer in architecture at the University of Minnesota and a founder of Friends of Tower Hill Park.

Ari Parritz, development manager for Vermilion Development, called the lawsuit's assertions "ludicrous."

The Witch’s Hat tower near Minneapolis’ Prospect Park is known for the great views it affords those who climb to its top.

"We hold tremendous and sincere respect for the community of Prospect Park and for Tower Hill and the Witch's Hat, and we're honored to be contributing to the area's growth along the green line," Parritz wrote via e-mail. "The baselessness of this lawsuit is a painful smear on the positive nature of all of our relations to date."

According to Parritz, the condo tower would be north of the Witch's Hat tower and could not block the view toward the Capitol. "The only view it could impact is that of the Hubbard Broadcasting Antenna, and hopefully the annual visitors to the top of the tower will forgive us for that," he wrote.

Chicago-based Vermilion Development wants to build its mixed-use project around the Art and Architecture building down the hill on University Avenue.

The project received approval from the Prospect Park Association, the Minneapolis Planning Commission and the City Council, Parritz said. He said he hopes to close on the land and break ground in early 2019.

During meetings with neighborhood groups, residents were concerned the high-rise would block views of and from the tower, Parritz said. As a result, the design was scaled back from an original 17 stories to what is now "basically at the same level" of the water tower's observation deck.

Still, Friends of Tower Hill Park say there is broad support to protect the water tower, which was built in 1913, decommissioned in 1952 and added to the National Register of Historic Places in 1997.

Lindt said opponents of the development are following the process after the city rejected a petition for an environmental review of the project earlier this year. Any construction near the park, she said, should respect the historic setting of the Witch's Hat tower.

She added that Friends of Tower Hill Park would like to have the observation deck open at least three seasons a year.

No hearing date was assigned to the lawsuit, filed in Hennepin County District Court, as of Tuesday evening.

Miguel Otárola • 612-673-4753