Which proposed Kendall Square park is your favorite?

Glenn KnicKrehm has a beautiful vision for Kendall Square – a cutting-edge, four-stage opera house and “village of art” upon which he’s done an incalculable amount of research, hopscotching around the world to ensure every last detail is acoustically and aesthetically perfect.

But that’s been the plan for more than two decades, and it’s not clear his Constellation Center is any closer to happening. It was once expected to open in 2012; three years later, with no progress seen, KnicKrehm offered to install a temporary park to beautify the area while he continued to fundraise the $300 million or so needed to make that vision come true. The park design was supposed to go before the Planning Board for approval last year, but “something got disconnected there,” in the words of city staff.

Two years later, there’s still just a field of gravel surrounded by a chain-link fence on KnicKrehm’s land. Almost five months ago he said he was in negotiations that would lead to an announcement “in a few weeks.” Now he says negotiations remain ongoing, while the Community Development Department reports no movement on a park.

Across the street is another situation unfair to Kendall Square and the residents of Cambridge: The imminent redevelopment of 14 acres of federal government land, but with green space dramatically shrunken compared with what’s been expected going back to 2001. Then the talk was of a 7.5-acre park, and the city approved dense developments with that dangling before residents and elected officials. Now planners say a speckling of greenery throughout the area makes a large central park unnecessary, and the finances of development on the government’s Volpe site make it all but impossible – bringing obscure formulations of open space (“more than three acres of ‘publicly beneficial open space,’ of which at least two will be contiguous”) that sound like the weird math rejected in calculating public space at East Cambridge’s empty Foundry building. Elkus Manfredi Architects have presented four schemes for the government’s Volpe site, and none impress.

What can be done to fix the impossible? For one thing, if a skyscraper wins back open space, it should be considered. A 500-foot building would be tall for Cambridge, but might not make much of a difference; councillor Leland Cheung has proposed a soaring, signature tower of 1,000 feet.

ConstellationCenter, once expected to open in 2005 and 2012, remains a gravel field in the heart of Kendall Square. (Image: Google)

And, while it is no joy to propose it, KnicKrehm’s languishing property is an acre of unused urban blight, and if he cannot prove his plan for the Constellation Center is happening – and cannot even move to provide his pop-up park – it may be time to procure or, if necessary, seize the land. Use it for structures that would otherwise go on the Volpe parcel, and add his acre to guarantee a bigger combined open space.

KnicKrehm is a sincere, well-liked man with an admirable dream. But the situation is simple: His plan may not happen, and the Volpe redevelopment will; that would mean two adjoining, permanently broken promises for Kendall Square. City officials should consider how to prevent that before it’s too late.

KnicKrehm may even want to donate the land to the city, with the stipulation that its inclusion on the Volpe site has an open-air performance area that, in good weather, can host opera, drama and dance of a kind once anticipated for his Constellation Center.