In 1975 a two-acre outdoor public space called Peavey Plaza opened in downtown Minneapolis, offering city dwellers an “urban oasis” at a time when many Americans were re-embracing city life, its designer, M. Paul Friedberg, said in a recent interview. Using a 10-foot depression created during construction of the adjacent Orchestra Hall, Mr. Friedberg, a Modernist landscape architect based in New York, built a terraced amphitheaterlike space and a drainable reflecting pool that could be used as a stage in summer and a skating rink in winter. Waterfalls absorbed noise; garden rooms offered intimacy and softened concrete edges. In 1999 the American Society of Landscape Architects recognized the plaza as one of the nation’s most significant examples of landscape architecture, along with Central Park in Manhattan and the Biltmore estate in North Carolina.


But things have changed. These days two of the plaza’s three fountains no longer work, their pumps and lines not easily replaceable. Concrete is stained and crumbling, exposing rebar. The reflecting pool is dry more often than not. And those intimate spaces are occasionally put to unsavory uses. Peavey Plaza’s time may be up. Even as preservationists argue for rehabilitation of what they consider the finest surviving example of Mr. Friedberg’s work, the City of Minneapolis, which owns 75 percent of it, has commissioned a significant redesign of the space. The plaza has become another battleground in the wars being fought around the country between preservationists determined to save what they see as underappreciated Modernist designs and cities and developers pushing to move on.


On Thursday the city’s public works department will appeal the Minneapolis Heritage Preservation Commission’s recent denial of a demolition permit, and if the permit is approved, the issue will be voted on by the City Council on May 25. Fund-raising has begun for a new design by Tom Oslund of Oslund and Associates, a Minneapolis firm, which is expected to cost between $8 million and $10 million, with $2 million provided by state bond funds.


“Even though Peavey Plaza is not a city landmark, the commission is considering it to be an historic resource worthy of further study and possible designation,” said Chad M. Larsen, chairman of the preservation commission.


Whatever it may once have been, the plaza “is not a beautiful space now,” said Gwen Pappas, the director of public relations for the Minnesota Orchestra, which owns 25 percent of it and has used the planned $50 million remodeling of its 1974 building to generate momentum for remaking the plaza. “The concern was if the hall was to get a shiny, new refurbishment and Peavey was left in its current state of disrepair, the discrepancy between the two would be even greater,” she said.


In addition, the city points out that Peavey Plaza meets neither Americans With Disabilities Act accessibility requirements nor sustainable water-use standards, and that it lacks the electrical supplies necessary for outdoor events. Mr. Oslund’s design addresses those issues and also creates a more open space, sunken less deeply below street level.


Supporters of rehabilitating Mr. Friedberg’s design say the city has not met its legal obligation to prove “that there are no reasonable alternatives to the demolition” as required by the code of ordinances on historic resources.


In June a group of people recruited to give feedback on proposed changes to the plaza was shown four concepts with preliminary budgets, said Erin Hanafin Berg, a member of the group and a field representative for the Preservation Alliance of Minnesota, which supports saving Mr. Friedberg’s design. In July the group was told that the city would move forward with developing two of those concepts, both by Mr. Oslund: a new scheme and one that adapted the original design.


But at an October meeting, “it was a rude shock when only the new, reconfigured scheme was on the table, and we were told that the restorative scheme was unfundable,” Ms. Berg wrote in an e-mail. In its demolition application, the city maintained that no feasible alternative was available because of the scope of construction and because funders would not contribute millions of dollars to restore the original design.


“There have been some conversations” with potential funders, said Charles T. Lutz, deputy director of the city’s Community Planning and Economic Development Department. They believe Mr. Oslund’s design “better reflects what is needed on the plaza today,” he added.


Mr. Friedberg had originally been on Mr. Oslund’s team; in an e-mail, Mr. Oslund said he removed Mr. Friedberg after he made it clear that he thought the plaza should not change.


Mr. Friedberg, who has recently come up with a set of design additions to Peavey Plaza that he believes would bring the space “into the 21st century,” said he would be open to more extreme change “if I thought what was being created advanced the idea of landscape architecture and urban culture.” Mr. Oslund’s design, in his opinion, “is not a significant view in that direction.”