The folks at King County Parks have come up with a new proposal for Seattle Center, creating a large open green space where KeyArena now stands. The proposal, which is being pushed by King County Executive Ron Sims, is touted as a way to plan for life after the Sonics (at least at the Key), as a way to handle stormwater runoff better, to solve some Metro Transit problems, and to give Seattle a major downtown park. And did I mention all the art?

It's an exciting and comprehensive proposal for "turning gray space into green space." But first, you might reasonably ask, what is the county doing telling the City of Seattle how to design Seattle Center? Particularly when the city is deep into a process, called the Century 21 Committee, to create more open space at the Center? Is Ron Sims trying to muscle his way into a sacred Seattle space? Doesn't this man have enough on his plate, now that he's taken on the whole Proposition 1 roads-and-transit plan?

Sims explains his unveiling of the Seattle Center plan (you're reading it here first) as "a hint" to the city. By that he means that the county has a surprising number of cards to play for the Center. As the boss of the Municipality of Metropolitan Seattle (Metro for short), King County is charged with treating stormwater, and so it legitimately wants to take a lot of the runoff water from the Center and stop dumping it, laced with pollutants, into Puget Sound. Hence the idea for capturing 100 percent of the stormwater generated by 74-acre Seattle Center and treating it through a series of attractive raingardens, pools, and vegetated swales as it makes its way down several streets to Elliott Bay and Lake Union. Metro also runs our bus system, and Sims and his staff have in mind a transit hub on Mercer Street (perhaps replacing the poorly designed Mercer Garage across from McCaw Hall) that would turn Mercer into a major bus route, intercept buses coming in from the north, and link up with a Lake Union-to-Sculpture Park trolley and maybe the Monorail.

Then there is KeyArena. It is likely, whatever the eventual outcome of the Sonics negotiations, that a significant portion of stadium-related money, such as hotel-motel and car-rental taxes, will be coming to the Center and any new arena. Should the Sonics leave the Center, mitigation money to the Center is likely to come from those sports taxes. Here's the catch. Those funds, while authorized at the state level, flow through King County, not the city, since they are collected countywide. So Sims would have to propose how they should be used to the King County Council, and that council would have to agree. Get the picture? In short, Sims can step on the oxygen hose to any solution to KeyArena, post-Sonics. The city has not been talking to Sims at all about its new plans for the Center, including a likely 2008 levy campaign. Going public with his scheme is meant to prompt a few phone calls, to see if, just maybe, Sims has any suggestions ...

Suggestions he has, for Sims has taken a pretty active dislike to the neglected Center. He favors much more open space, jogging trails, a big open amphitheatre for concerts, sculpture, and lots of activation of the open spaces by putting artists, retail, and residents nearby. (Disclosure moment: I've been involved with some other citizens in pushing for a more park-like Seattle Center, replacing Memorial Stadium, the Fun Forest, and Center House with open space.) Sims has shifted the focus of other park advocates by looking at the western edge and tackling the big question of the Center, what to do about Key Arena. He fears that if the Sonics move to a larger new arena somewhere in the region, KeyArena will face a lingering death, as has been the case in many other cities. Sims thinks the plans he's seen so far for carving up the Key and making do with second-best space would turn into "another government statement." Better to get out ahead of that by simply tearing it down, capturing some new open space north and south of the Key, and ending up with a beautiful park in that space rather than a relic.

The usual objection to more open space in an urban setting is that it would just sit there, lightly used and vaguely unsafe during the non-summer months. Sims therefore proposes to put the park right up against the lively urban village of Lower Queen Anne, adding more retail, restaurants, and other activity generators along the park's western edge. He adds lots of public art, walking paths, a pervious running trail (like Green Lake's), and numerous rainy-weather attractions. His planners put a large water feature near the center of the new space, where the stormwater is held and released before following landscaped "canals" across the Center and down several streets to the Sound and Lake Union.

Sims also brings a lot of people to the Center by routing a proposed streetcar or trolley up from the waterfront, along the western and northern edges of the Center, and on eastward to Lake Union Park and the connection with the South Lake Union Streetcar. The transit hub proposed for Mercer Street would turn Mercer into a transit spine, give bus riders an easier way to and from the Center, collect commuters, and help make the Center a transit nexus for all its many uses. Finally, as with the Century 21 Committee's plan, Sims builds a large outdoor amphitheatre for summer concerts. Sims puts his amphitheatre in new space in the southwest corner of the Center, while the Century 21 folks put it atop Memorial Stadium or over by the Space Needle.

Like many local politicians, Sims has made his pilgrimmage to Chicago's stunning new Millennium Park, where bold artwork, a dazzling outdoor amphitheatre, and lovely gardens (designed by Seattle-based Kathryn Gustafson) have created the most exciting urban park in decades. He's seen what the Olympic Sculpture Park has done, attracting 400,000 visitors since it opened early this year and touching off lots of new residential construction on its edges. Sims has got religion on sustainability, and he knows how much green space resonates with the new ethic of addressing climate change, in part by attracting more people to live in denser quarters by giving them generous public open space.

As with Sims' famous switcheroo on the Sound Transit proposal (which he steered for many years and now opposes), he's very late in getting into the Seattle Center game. The city's planning, which also has embraced a greenheart for Seattle Center, puts that space where the run-down Fun Forest now sits and where the Memorial Stadium, also run-down, now perches. That assumes, of course that the city can pry the stadium away from Seattle Public Schools, no easy feat. At any rate, the city's planners have stayed away from making any decisions on KeyArena, partly because its fate is unknown (and we're likely years from a decision). Other factors fending off bright ideas for the arena are the large number of union jobs there and the lucrative parking revenue the Center gets from Sonics games and big rock concerts. To be sure, Sims, like city planners, leaves untouched such popular elements as the row of theaters along Mercer, the big fountain, the Science Center, Center House, EMP, the Children's Theater, and the Space Needle.