The high impervious surface costs of Austin’s current zoning scheme

The high impervious surface costs of Austin’s current zoning scheme

February 8, 2018 Off By Ashkan Jahangiri

In December, the City of Austin Watershed Department released a memo that looks at the impervious surface impacts of two alternatives: keeping current zoning or switching to the draft CodeNEXT V.2. They looked at the expected impervious surface in the full buildout scenario – meaning that every entitlement would be used up – something that never happens. But it provides a useful way to compare two plans for future growth.

And so far it seems most discussions of this memo completely miss the powerful findings.

Their conclusion was that the proposed CodeNEXT V.2 was a slight improvement over current zoning, with about 1,200 less acres of land paved over in the city or about 1% of the city left open rather than paved, because of the change.

This is already a very strong rebuke of any claims that keeping the current zoning is good for flooding or environmentally friendly.

However, we can go further, because these two scenarios actually mean quite different things in terms of the numbers of people allowed to live in the City of Austin. Allowing more people to live in the City of Austin not only is the most significant step we can make to counter displacement, but also has a tremendous environmental advantage.

When we take the different future populations into account, we see that these two paths represent dramatically different future impervious surface per capita for the people of the City of Austin and the region. In these two scenarios, the CodeNEXT V.2 future would mean each resident of the City of Austin were responsible for almost 1,000 less square feet of impervious surface, compared to the future we expect if we keep the current zoning scheme.

There are also regional impervious surface benefits of this shift just inside the City of Austin toward more sustainable compact, connected development. If a lot more people lived inside the City of Austin, thus not living the high impervious surface per capita lifestyle that most new housing in our region outside the city of Austin provides,  the total regional effects would be dramatic. And these benefits are not captured in this current analysis. So we could similarly go further with this argument and intend to do so.

But this chart is already a very strong rebuke to anyone pretending to claim environmental or flooding or water quality (or heat island) reasons to argue against CodeNEXT in favor of keeping the current zoning code that has caused so many localized flooding problems for Austin.

Join us Friday, February 16 for the 3rd of 4 events in the Growing Weirder Breakfast Seriesto talk about this and other environmental sustainability issues related to regional growth, CodeNEXT, and the regional transportation plan. Get your tickets today.