West Campus grew like gangbusters between 2000 and 2010. I've tried to convey how remarkable this growth truly was. In 2000, tracts 6.03 and 6.04 had 5,273 and 5,199 inhabitants, respectively. In 2010, they had 7,793 and 6,496 inhabitants, respectively. Austin's two densest neighborhoods thus grew by 36%, outpacing Austin's 20% growth (much of which took place in cow pastures).
Perhaps looking at the change in population density is more impressive. In 2000, tracts 6.03 and 6.04 had densities of 17,288 and 19,645 ppsm. In 2010, they had densities of 25,550 and 25,276 ppsm. (It's interesting that when density restrictions were loosened via the West Campus/University Neighborhood Overlay, these adjacent neighborhoods converged to the same density.)
A map is better than 115 words, though. A reader pointed me to this Campo map of building permits issued in West Campus between 2005 and 2009. This is what growth must look like for a dense neighborhood to become significantly denser:
Three points here. First, and obviously, a dense neighborhood cannot grow noticeably denser without lots and lots of new construction. Three or four projects scattered around the neighborhood might look like a lot, but a 40% increase in density means, literally, new construction everywhere you look.
Second, lots and lots of new construction means the destruction of lots and lots of low-intensity buildings, particularly single-family homes and smaller, older apartment buildings. It must be this way because a neighborhood wouldn't be dense to begin with if it weren't already built out. Restrictions aimed at preserving existing buildings necessarily cap density, despite the frequent denial by activists. And always remember that "denser" is shorthand for "room for more people." The West Campus growth between 2000 and 2010 required the destruction of lots of older apartment buildings. It also made room for 3,700 more people. You can cling to old buildings or you can make room for more people; you can't do both, unless you're satisfied with making room only for a lucky few.
Third, almost all of the permits were issued for construction in the neighborhood interior. Again, it has to be this way if a neighborhood is to add a lot of people. Most of the space is in the interior. That's just geometry: a 10-block by 10-block neighborhood has 100 blocks but only 36 blocks on its perimeter. What's more, new construction in the interior only has to compete with other residential uses; residential uses on the perimenter have to compete with commercial uses. Vertical mixed uses are great and I've long advocated that we allow them freely on our busy streets, but they will always be more expensive to build. And to manage -- there are practical problems mixing retail and residential uses in the same building. There are standard techniques for handling them, but they require extra work, which isn't free.
No one is advocating the wholesale replacement of single-family homes in neighborhoods like Bouldin and Zilker with the massive apartment buildings like those in West Campus. But if we really want to make room for more people in these neighborhoods, we cannot relegate new construction to their fringes. A good start would be to permit small multi-family projects (four units or so) as a matter of right but adopt reasonable design standards to protect their neighbors. It's a conversation that needs to take place regardless, and it should begin with a clear understanding of what making space for more people really means.