9 thoughts on “Nirenberg: City Reviewing ‘Pandora’s Box’ of Impervious Cover Policies

  1. It’s about time. Impervious cover affects everyone who gets a SAWS bill in the City. Your stormwater fee is based on how much impervious cover you have. It used to be based on lot size only – and that wasn’t great, either.

    As it stands now, my mid-century ranch on a half-acre lot has lots of trees and reasonable grass, flower and vegetable beds (and low-water bills, I’m frugal) has minimal storm runoff and a very gentle slope. I even capture rainwater for hand watering. But I pay the same or more than similar sized houses densely built with minimum setbacks on steep slopes in caliche soils with few trees in the northern part of the city (I’m looking at you, Stone Oak…). Larger setbacks, or smaller houses on the small lots would help – but that can contribute to sprawl, so it’s not easy.

    Regardless, the “Federal Stormwater Fee” has no business on your SAWS bill. It’s a payment to the City based on physical improvements made to real property – and that sounds an awful lot like a property tax. If you want to tax me, then tax me, but call it what it is and get it off my SAWS bill.

  2. The focus on impervious cover at the site- or lot-level biases this discussion towards poor decisions. The photo at the top of this article illustrates that bias. It suggests that densely built areas are the core of the problem. That leads to the conclusion that suburban property on a large lot is the solution. The outcome is individual sites that may better manage water, connecting big box stores and lots and lots of parking with wider and wider streets. A development with 100 homes of 3,000 sf with 30 foot setbacks on half acre lots has more impervious cover as 100 homes of 3,000 sf on one-eighth acre lots and 10 foot setbacks, but the large lots require more pavement. Either of those will have more impervious cover than 100 two-story townhouses in a neighborhood where the preferred travel mode is walking.

    • On an absolute basis, I might agree with you, but on a relative, site- or lot-level basis, I can’t.On an absolute basis, I might agree with you, but on a relative, site- or lot-level basis, I can’t.

      A 2-story 3,000 sf home on a 1/8th acre lot, with an attached 2-car garage, driveway and sidewalks is about 60-70% impervious cover – just on the lot, before y0u factor in roads and supporting infrastructure. Relative to the lot, the water has nowhere to go, so it flows into the street. Postage stamp lots with McMansions on them are a real problem. On a developmental scale (x 100 houses…) a minimum permeable cover ratio per home site may be necessary – which means code or plat restrictions – which means changes to the law to eliminate “grandfathered” plats. Good luck fighting the developers.

      100 2-story townhouses are surrounded by what? Parking lots, or are they built with “luxury” attached garages? Where are the trees for air quality and shade, over in Hardberger Park? What about the strip malls with the restaurants that pop up to serve them? How many supermarkets are there near the Pearl? Does anyone actually walk to the Pearl?

      Use the example of San Marcos student apartments and 2015 flooding. Super-dense housing, poorly built and sited relative to the natural drainage systems contributed to much worse flooding than previously because they densely built up and out and pushed the runoff away.

      You MUST consider the individual “site” and its capacity to absorb or propensity to shed water.

      Large lots and sprawl aren’t the answer, but neither is a pipe-dream of dense urban infill townhomes. That ship sailed when San Antonio chose to use above-ground creeks and didn’t build a storm-sewer system. And again when San Antonio repeatedly votes against light-rail, and quibbles about supporting Via, and chose to support Vista Ridge…to meet the demands of large suburban lots.

      The impervious-cover question is in two parts: what is going to be done AND how is that going to be paid for.

  3. More talk, and I still count at least 15 vacant City of San Antonio sidewalk tree wells in my immediate area a few miles from downtown–when we are in prime tree planting season and meant to be planting a bunch of trees to help mark our Tricentennial.

    There’s no clear path to requesting a tree planting via the City’s main, 311 or SA300 websites. It’s no Pandora’s Box–just a lot of empty sidewalk boxes (filling up with stormwater) and no action.

  4. Remember, there are other impacts to sustainability that need to be factored in to the equation. Martha’s earlier point is one, but adding to that is a lower density sprawling city will result in more vehicle miles travelled (VMT) and bring with it several adverse impacts. Those include carbon pollution, additional natural resources to build the extra infrastructure (roads, sewer lines, ugly overhead power lines, etc..) as well as the adverse impact to quality of life by being subjected to longer commutes. These are simply the reality of lower density development.

  5. Not all impervious cover is equal—it’s not all bad. These surfaces provide a ready-made alternative to San Antonio’s worst nightmare, an inevitable shortage of its existing water supply. To reduce damaging runoff and increase the water supply, an innovative solution would be to encourage rainwater harvesting far beyond the existing levels. One need only look below the ground to realize this practice is not new, just forgotten. Well before there was a SAWS that could import other people’s water as an alternative to a finite quantity of water from the Edwards Aquifer, cisterns were commonly used to store rainwater. A brick one, assumed to be built at the time of construction in the 1870’s, was discovered at the Halff House in Hemisfair Park. In downtown San Antonio, a similarly constructed cistern of a comparable time period was uncovered by a work crew during excavation work for the San Antonio Fish Market and Bakery Restaurant at the corner of Saint Mary’s Street and Commerce Street. According to the Texas Water Development Board Rainwater Harvesting Manual: “Such notable historic structures as the Stillman House in Brownsville, the Fulton Mansion near Rockport, the Freeman Plantation near Palestine and the Carrington-Couvert House in Austin collected rain from their roofs, and then guttered and piped the water into an aboveground tank or cellar cistern. While many of these systems are no longer in use, they signify the importance that early Texas settlers placed on captured rainfall for sustenance.” In Houston, rainwater was captured in a massive 15 million gallon underground cistern built in 1926 and used it as water supply until 2007. Clearly, appropriate regulation of impervious cover is in the future for San Antonio. Yet, the city need only look to the past for innovation that can reduce that damaging runoff today and create a local, renewable source of water for tomorrow—rainwater harvesting.

  6. I’m revisiting this thread for a variety of reasons, but foremost is a lack of leadership or cohesive coordination.

    A factor in runoff that was mentioned in several comments is rainwater capture via barrels or cisterns. Did anyone know that just this week “large cisterns” were a topic at this week’s SAWS Community Conservation Committee? https://www.saws.org/who_we_are/community/ccc/docs/CCC_Agenda_20180110.pdf

    Did anyone even know there was a meeting? Did you know that the minutes of this meeting will likely never be published, based on past record?

    Why not? Because it wasn’t publicized! SAWS didn’t list it. The Mayor didn’t promote it. The Councilman (D9) who has the current Chair of the Committee doesn’t follow up on it. And the vast majority of San Antonians are blissfully ignorant.

    Task forces, working groups, community involvement doesn’t amount to a hill of beans if the powers-that-be aren’t held accountable to actually addressing the problems.

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