Harvey revives flooding concerns about CodeNEXT

In the wake of Hurricane Harvey, the land use commissions questioned staff on how CodeNEXT would address local flooding at their Aug. 29 joint meeting. “Austin came real close to having another catastrophe this (past) weekend. Real close,” Zoning and Platting Commissioner Ana Aguirre said at the meeting.

The storm event has opened up a national conversation on how city planning contributes to flooding, particularly in the case of impervious cover. As cities like Houston or Austin continue to develop, the inevitable result is more runoff after rainfall.

There are ways to mitigate it, though, and the CodeNEXT planners have high hopes for tools included in the new land use code. “CodeNEXT will do a much better job than what is currently on the books,” said Planning and Zoning Director Greg Guernsey.

In particular, the Watershed Protection Department has proposed a new regulation that would require redevelopment projects to retrofit the property with flood mitigation measures, like on-site detention ponds. Guernsey also mentioned that anyone can go to the city’s website to view flood plain maps.

Aguirre pointed out that what was missing from the data available on the city’s website was information on localized flooding, or flooding that specifically results from runoff or inadequate drainage systems as opposed to creek flooding when rivers overflow. “All of the properties (at risk of localized flooding) need to be identified. All of those properties should be included in the (CodeNEXT) mapping process,” she said.

Despite Guernsey’s reassurances that flood plain maps are being incorporated into the CodeNEXT maps, Planning Commissioner Karen McGraw said that if the risk of flood for a zoning district was not made explicit, especially if that district is upzoned through CodeNEXT, it might lead to future problems. “Why would we intentionally give away entitlements in a place that floods?” she asked.

Guernsey clarified that there are already regulations in place that prohibit new development in flood plain areas and also require Council approval for any additions to existing structures in those areas. McGraw disagreed and said that developers and homeowners are able to obtain waivers too easily. “I don’t think we want to make that a more prevalent situation,” she said.

The main obstacle faced by planners who want to use zoning to enforce flood mitigation is that flood plains change, Guernsey explained. Regional detention facilities may be constructed that remove properties from a flood plain, but if they were zoned as if they were in a flood plain then they would have to request a zoning change, a lengthy process.

Regardless, Zoning and Platting Commissioner Ann Denkler echoed her colleague’s calls for Watershed staff to present at a future joint meeting, because the CodeNEXT map could be integrating assumptions made by staff that the commissions and the public at large are being excluded from. She recalled investigating where a regional detention facility could be constructed to accommodate the Grove Planned Unit Development before it was approved, and she discovered that there weren’t any suitable sites for it along Shoal Creek.

“This isn’t just a matter of flood plains. It’s a matter of the mapping and how it relates to the stormwater infrastructure,” she said. “We’re not just buying out homes in Onion Creek. We didn’t just buy them out in Shoal Creek. (We) just spent $2 million on February Drive in District 1. That was an area annexed (into the city) with no curb and gutter.”

For context, about a quarter of the city’s storm pipes were constructed before 1977, before modern engineering standards had even been adopted.

Guernsey said that he would talk to Watershed staff and see when they could participate in a dialogue with the land use commissions.

Curious about how we got here? Check out the Austin Monitor’s CodeNEXT Timeline.

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