If New York can do it, anyplace can.
If New York can do it, anyplace can.

Not far from my house, there is a reservoir and an elderly sand-filtration water-treatment plant that is no longer in service. As with so many things in the District of Columbia, its future use is the subject of heated debate. As I understand the history of the place, the city could have gotten the site for free from the federal government to use as a park, but instead bought it so that it could be developed for residential housing. As that development moves forward, a bitter dispute has grown between the Friends of McMillan Park, who would like to make it a park, and the locals who want more housing there.

As with so many of these debates, the argument roughly tracks the demographic change in the city, though far from perfectly: In general, young white gentrifiers think that obviously it should become housing, and the neighborhood's old guard thinks that it should be converted into a park. The urbanophiles who discuss it among themselves seem to largely think this is a no-brainer, the resistance a result of atavistic fear of neighborhood change and a deplorable ignorance of the economics of home prices.

Well, I think I understand the economics of housing prices pretty well. Nonetheless, I'm with the Friends of McMillan: The site should be turned into a park and the housing pressure relieved by upzoning nearby areas. It's not an opinion I'm too vocal about, because the arguments tend to be tedious and repetitive. But now that I've gone ahead and stated an opinion, let me explain. It's pretty simple, really: Dense cities need big parks to thrive.

I grew up in Manhattan, and I'm quite fond of dense living. I like having neighbors on either side of me, a few inches away. It doesn't feel oppressive or crowded; it feels cozy.

But if you want people to commit to lifelong density, they need some open space to escape to -- somewhere they can walk to. It's no accident that New York has an extensive park within walking distance of so many of its dense neighborhoods; it's the safety valve that allows people to live in such close quarters without killing each other. Very dense cities such as New York are exciting places to live, but they also produce high levels of psychological stress in the people who live there. Parks can help soothe some of that distress, making it easy to spend the rest of the day surrounded by strangers.

Unfortunately, the area of D.C. in question doesn't have much in the way of open space other than cemeteries and McMillan. If we build there, we're pretty much giving up on the idea of having a big park within walking distance. (There will be a park included as part of the new development, but it will be pretty small.)

Parks are especially important, of course, for people with kids, which describes relatively few of the pro-development side. And as Lydia DePillis recently noted, D.C. has a kid problem. We're doing a top-notch job of building a lifestyle city for childless young people (and some hip empty nesters). We're doing a much less good job building a sustainable environment in which people can hope to pass through their whole life cycles.

For many reasons, a city composed mostly of old and young affluent people, and little in between, seems likely to me to be one with great bars and food truck regulations but weak communities and low-quality governance. As long as the city is a way station rather than a permanent destination, people will underinvest in public goods such as educated voting and community organizations or fighting corruption. Also, children are cute and nice to have around, and we'll have more of them if there is somewhere convenient for Mom and Dad to take them to play.

Don't get me wrong: I'm not arguing that parks are the only thing standing between D.C. and a baby boom. Schools are a far more important determinant of whether parents stay. But the way you improve the schools is, by and large, to get a critical mass of middle-class parents who can invest a lot of time and energy (and money!) into improving the schools. And one way you entice that critical mass to stay here is to give them somewhere to take the kids.

Then there are those of us with dogs, and those of us who jog or like to take long walks in some green space. A park is a major public amenity, and we should strive to balance those needs with the need for more housing. I understand that a large package of land such as McMillan is an enticing development target, but buildings can be built on smaller parcels of land. A nice, big, refreshing green space can't. In paving over most of McMillan, I fear we're making the same mistakes as the urban-renewal people in the 1960s: conceiving of neighborhoods as "machines for living" rather than organic spaces.

Of course, that leaves us with an affordable-housing shortage. Frankly, building 50-story skyscrapers in that space would still leave us with an affordable-housing shortage, and we can't build anything like that in the area, not only because of the height limit, but also because the area has no close Metro access, which limits the number of people you can move in without completely overloading the nearby streets. Nonetheless, we need more housing, and McMillan would certainly provide some if we developed it. So I have a trade to propose: Upzone the area around the park for higher density. The city ought to be able to make a nice packet of money off the property taxes, what with all those lovely park views.

This column does not necessarily reflect the opinion of Bloomberg View's editorial board or Bloomberg LP, its owners and investors.

To contact the author on this story:
Megan McArdle at mmcardle3@bloomberg.net

To contact the editor on this story:
Brooke Sample at bsample1@bloomberg.net