Hurricane Harvey brought an estimated nine trillion gallons of water into the streets of Houston, bringing America’s fourth largest city to its knees. In the wake of the disaster, many urbanists asked: To what extent did Houston’s unconventional approach to planning make the damage worse?
Before the rain stopped falling, more than a few writers laid the blame for some of the damage at the feet of Houston’s lack of zoning and the region’s startling horizontal growth. Others pointed to Houston’s rapidly spreading impervious surfaces, often in the form of surface parking lots and roads, which prevent water from soaking into the ground, adding to runoff and increasing the speed of flowing water. Since 2010 alone, area officials have approved the construction of over 7,000 houses in 100-year floodplains. Much of this development also occurred in prairie wetlands, reducing the region’s capacity to absorb the extreme amounts of water dumped onto the city by Harvey.
But while some new construction happened within Houston proper, most of it occurred in Houston’s conventionally zoned suburbs; as Mayor Sylvester Turner recently put it, “Zoning wouldn’t have changed anything. We would have been a city with zoning that flooded.”
There is no doubt that developing on wetlands and adding too much impervious surface contributed to the catastrophic shape of the Houston region’s flooding. But for the most part, these problems have very little to do with zoning. Houston does lack conventional Euclidian zoning—residents have voted it down three times, most recently in 1994. But lacking Euclidian zoning just means that Houston doesn’t strictly separate land uses and densities—that is to say, the city doesn’t forcibly separate things like single-family homes, apartments, groceries, and offices. In practice, this means is that Houston lacks several of the land-use regulations that many urbanists today revile. Most of these regulations—from floor area ratios to banning accessory dwelling units—have very little to do with developing in floodplains, and largely serve to restrict dense urban development.
Beyond not segregating uses, Houston’s approach to planning is unique in that it doesn’t artificially limit densities or throw up barriers to dense urban redevelopment. This is generally good if you care about housing affordability or racial segregation, since it keeps NIMBYs from blocking new multi-family housing. Unlike San Francisco or Boston, Houston lacks a lot of the discretionary reviews and “neighborhood vetoes,” making it much easier to convert single-family homes in high-demand areas into apartments or townhouses. This also makes dense infill redevelopment much easier, which allows cities to grow up and become more dense. Where the zoning in most cities pushes new development out into the suburbs, Houston keeps it easy to add more housing in desirable urban neighborhoods. Ironically, if we are concerned about destructive greenfield development, Houston’s lack of zoning almost certainly helps more than it hurts.
In this sense, Houston’s lack of zoning could prove to be an advantage when it comes to recovering and rebuilding in a sustainable way. Early estimates put the number of homes destroyed at 40,000 and many more partially damaged homes will likely be demolished in the coming weeks and months. We also know that if we want to avoid worsening the next flood, new housing can’t go back into wetlands or onto sensitive greenfields. With the risks of suburban development clear and over 500,000 cars waterlogged, many residents displaced by flooding may look to urban Houston for a new home. Houston is going to need a lot of new housing, and most of it will need to go into the city’s existing urban areas.
Happily, Houston’s unique, hands-off approach means that building dense new housing in the city is easy. Consider that over the last few years, Houston has been undergoing an unprecedented boom in multifamily housing construction. In 2016 alone, Houston built an estimated 25,000 apartments, much higher than considerably larger cities like New York and Los Angeles. Few other cities of Houston’s size would have the administrative capacity or willingness to facilitate the massive urban rebuilding that will be needed post-Harvey, and this is largely thanks to Houston’s lack of zoning and flexible approach to urban development.
For planners, the key will be to make the tweaks needed to keep this massive redevelopment from worsening future extreme weather events. First, planners could eliminate the city’s minimum parking requirements. Where land is cheap and parking requirements are high, these requirements force developers to build large surface parking lots, resulting in hundreds of acres of impervious surface across the city. As the rebuilding process starts, it would be silly to see developers forced to rebuild them.
Second, state and local policymakers should set aside more funds for the purchase of development rights, allowing the city to buy from landowners the right to develop their property. This has the benefit of preserving sensitive wetlands and environments before they are developed. Where wetlands were already developed, the city should buy out property owners and convert the land back into wetlands. Both solutions could expand and protect water-absorbent wetlands without running afoul of Houston’s famous reverence for property rights.
Finally, policymakers in Houston and surrounding municipalities could expand incentives for new developments and renovations that incorporate stormwater mitigation into their design. Less impervious surface and more wetlands preservation will help on the margin, but as The Atlantic’s Ian Bogost pointed out, planners still need to find a place to put all that water during extreme weather. Expanding incentives to add cisterns, green roofs, and detention ponds to new development could help to address this challenge.
The trick will be expanding such programs not just in the city of Houston, but across the region, with its many levels of government and municipalities. Some municipalities have taken stormwater mitigation very seriously. But going forward, the state will probably need to tame the region’s tangled mess of 949 suburban Municipal Utility Districts, which manage local infrastructure. So far, they have largely dropped the ball on stormwater management. If Houston is going to manage nine trillion gallons of water again, it’s going to need help.