Water quality experts believe that these types of landscape and design features, known as low-impact development, or LID, are both an important part of solving San Antonio’s problems with environmentally degraded waterways and flooding, particularly as the city continues to grow.
City planners expect about half a million new residential units here by 2040. With that comes more pavement and rooftops, surfaces known as impervious cover that prevent stormwater runoff from absorbing back into the ground and can make flooding more destructive and deadly.
Data from the U.S. Geological Survey show that the top annual floods along some San Antonio’s urban creeks and rivers have become more intense. All the city’s creeks and the San Antonio River carry levels of E. coli bacteria too high to allow safe swimming. San Antonio River Authority biologists say the cause is human and animal feces that wash off of impervious surfaces and into waterways when it rains.
These problems leave the city, Bexar County, SARA and others grappling with how best to manage flooding and water quality and whether the most effective way is through regulations or voluntary incentives.
The options come down to this: Continue to only send stormwater runoff downstream using pipes, culverts and similar hard infrastructure, which is the traditional method, or also incorporate LID tools.
LID includes about 10 landscaping and design features that let more water infiltrate the ground on site. Most involve plants, usually native ones, set in well-drained soil or gravel designed to catch storm runoff. Among them are permeable pavement, bioswales and rain gardens that act as natural filters. They capture the first flush of rainwater, the runoff most likely to carry concentrated pollutants that have built up over dry periods.
Such features also can help reduce flooding. Rain falling on pastureland will produce less runoff than rain falling on a new subdivision or strip mall that’s covered in pavement, experts say. LID mimics predevelopment conditions, slowing the stormwater as it travels off a site or giving it more time to absorb into the ground.
The point is “to go upstream as far as you possibly can and begin to treat water there and begin to capture water there and let the runoff soak into the soil instead of having huge detention facilities that are downstream,” said Larry Clark, landscape architect and vice president of Bender Wells Clark Design.
The firm has worked on LID projects across the city, including a large plaza of permeable pavement at VIA Metropolitan Transit’s new Centro Plaza. “All of those sorts of elements help reduce flooding on a small storm event particularly, and it just slows it (runoff) down and redistributes it so plants … help clean it up,” he said.
Increasingly, LID features are being incorporated into public buildings, such as the Convention Center expansion, the DoSeum’s new building on Broadway and the Mission Branch Library and Mission Marquee Plaza on the South Side. Clark’s VIA plaza site is more complex, involving a huge underground cistern and filter system that’s capable of handling a 100-year storm event and slowly releasing excess stormwater over a day.
Current flood projects in Bexar County
For now, with some minimal exceptions, San Antonio and Bexar County developers and builders do not have to include LID elements in their projects, though city and county codes encourage it.
Local officials have stitched together a tapestry of incentives and rebates to convince a skeptical development community that there are benefits to changing how they’ve done business for decades but without unduly increasing their costs.
SARA, the local champion of LID, developed a manual that outlines 10 such design features in depth.
“We have to come up with pragmatic rules that make sense,” said Steve Graham, SARA assistant general manager, and institute measures that “don’t double the price of the project.”
LID features, since they incorporate plants, also offer some aesthetic benefits that are harder to tie to a dollar amount, SARA watershed engineering manager Patrice Melancon said.
“People would rather be surrounded with green space than by concrete,” she said.
Old ways and new
Some engineers who design traditional drainage systems, “what they learned in school,” are now more open to considering LID techniques, said Afamia Elnakat, an engineering professor at the University of Texas at San Antonio who previously worked for Pape-Dawson Engineers and the engineering firm CH2M.
“The more they do it voluntarily, the easier it will be to promote positive change,” she said.
She would support modifying the city’s development code to incorporate LID, though in some locations, traditional methods, what she calls “hard engineering,” can be more effective.
Some think LID is more expensive to maintain, but that could be a misconception. Both require maintenance, but unkept LID projects might be more conspicuous. Cracked and clogged pipes and crumbling concrete can go unnoticed more than overgrown rain gardens or bioswales, she said.
“When you don’t maintain LID, it’s obvious because you might have water puddling, you might have a mosquito problem,” Elnakat said.
LID features may add some cost, but they can save in other ways, said Clark, the landscape architect. They can also be more affordable if they are included in a project from the beginning.
For example, at Hemisfair, new underground infiltration planters capture water off the pavement so it can be soaked up by plants. The remaining water slowly flows through a pipe and into the San Antonio River, Clark said.
That considerably reduces the amount and size of pipes and the number of stormwater inlets needed for a project, he said.
Generally, the cost of LID fluctuates based on the size and configuration of a site, said Irby Hightower, a founding principal of Alamo Architects.
“If you’re dealing with something that’s like an area that would normally be landscaped anyway, there’s very little cost,” Hightower said.
But in highly dense urban areas with little or no green space, costs can climb, he said. Large underground storage tanks can get expensive, or LID might result in a project having less parking.
That’s why some developers are still wary of LID or making it required. Additional costs, say on a single-family home, are always passed on to the buyer.
“I think the position of the development community is, if it proves out to be less expensive and beneficial, they’ll do it,” said Michael Moore, proprietor of Ironstone Development. “If it’s expensive and doesn’t provide any positive aspects to the drainage plan, they won’t do it.”
One LID method most widely used in San Antonio is a sand filter — usually a large detention structure that is heavily lined and uses sand to filter pollutants carried by runoff from buildings and pavement. Graham, with the river authority, calls sand filters “an abomination to the eye,” especially when property owners allow trash and weeds to accumulate there.
One reason so many developments use them, especially over the Edwards Aquifer recharge zone, has to do with the state’s aquifer protection regulations. To avoid the risk of polluted stormwater getting into the aquifer, state regulations require the retained water to be piped into a storm drain then into a creek or river, not allowing it to go into the ground.
To protect the aquifer, San Antonio has put some limits on impervious cover — buildings and pavement — over the recharge zone. Most developers,however, have been able to bypass the limits by relying on “vested rights,” as the Express-News reported in June. Four out of five projects — nearly 1,380 total — avoided impervious cover restrictions, according to San Antonio Water System data.
What other cities do
Some cities, including Lake Tahoe and Austin, have tried to address impervious cover and pollution through tighter rules on development. In some areas close to waterways, Austin prohibits impervious cover.
Graham said Austin’s policies go too far toward “environmental wackoism” and would not work in San Antonio. Still, there needs to be more done here to encourage LID, he said. The current incentives available here “aren’t strong enough.”
San Antonio developers, property owners, construction companies and engineers have resisted attempts to even bring up the idea of impervious cover restrictions beyond the recharge zone.
The most recent debate came in September, when the city’s Planning Commission voted to strip the city’s SA Tomorrow Sustainability Plan of language suggesting expanding the city’s impervious cover requirements beyond the recharge zone, “if deemed necessary.”
The language was opposed by the San Antonio Real Estate Council trade group, which said in a statement that it supported cover limits on the recharge zone but not elsewhere.
“The proposal that impervious cover limits should be applied citywide without a good reason is deeply concerning,” the statement read. “We are aware of no scientific rationale that has been put forth to support this proposal. There has been no cost-benefit analysis. Including such a proposal in the Sustainability Plan sends the wrong message to companies that are considering investing in San Antonio. Impervious cover limits increase the cost of doing business by requiring more land for every project. Impervious cover limits also increases sprawl, which is diametrically opposed to many of the goals of SA Tomorrow.”
Nothing about the SA Tomorrow plan is binding. Any changes to the city’s Unified Development Code would have to go through the City Council.
Council divided on mandates
The council is divided on how to tackle development issues long-term.
In an email last week, District 9 Councilman Joe Krier said he doesn’t know that imposing impervious cover regulations beyond the recharge zone “would outweigh the higher construction costs that would result — costs that builders always pass on to the buyers.”
District 10 Councilman Mike Gallagher expressed similar concerns that the city “could harm needed development if we start over-regulating.”
District 4 Councilman Rey Saldaña said he has watched the same push-and-pull over impervious cover play out since 2004, when former Mayor Ed Garza appointed a committee to examine whether the city had let too many property owners avoid restrictions on the recharge zone.
Most of the time, elected officials have given in to pressure from the business community, he said. This affects historically disadvantaged communities that have to deal with flash flooding created by rapid development upstream, he said.
“At some point, city policy should not only incentivize but require LID features,” Saldaña said.
District 3 Councilwoman Rebecca Viagran said in an email that limiting impervious cover is “worthy of consideration,” especially around the city’s creeks and river. LID “can be an important part of ensuring environmentally conscious growth and development,” she said, but it could have consequences for the availability of affordable housing.
“Low-impact development features like these are expensive and may be unattainable for many property owners,” Viagran said.
District 8 Councilman Ron Nirenberg, who’s become an ally of water conservationists across the city, said that right now, people are still getting comfortable with the notion of low-impact development, but he believes that the city needs to act faster.
“We know in terms of sustainability and best practices here and across the world that low-impact development helps control costs, is better for management of resources, natural and financial, and is something that we eventually need to get to,” Nirenberg said.
Last summer, council members ultimately compromised when it was their turn to adopt the SA Tomorrow Sustainability Plan. They agreed that a “representative” stakeholders group “study and consider” whether to expand the impervious cover ordinance.
Mayor Ivy Taylor said in an email that the stakeholder group could begin meetings and discussions after a similar group, led by the city’s chief sustainability officer, Doug Melnick, revisits parts of the city code that deal with too much lighting interference near military bases, particularly Camp Bullis.
The impervious cover group won’t convene until at least the spring, Melnick said.
Taylor said she recently met with SARA General Manager Suzanne Scott and board Chairman Mike Lackey “to begin discussions about their role and guidance regarding this process.” She did not answer questions about whether she supports changing the code.
Incentives or requirements?
To kickstart LID, both incentives and requirements are beginning to make their way into local policies.
In San Antonio, LID is mandatory only in areas that abut the San Antonio River.
Elsewhere in the city, with LID being voluntary, San Antonio adopted its first incentives, giving developers some leeway on other city requirements. For example, if a development incorporates some LID features, that will count toward meeting the city’s tree preservation requirements, said Gene Dawson Jr., president of Pape-Dawson Engineers.
So far, the city’s Transportation and Capital Improvements Department has approved three projects that meet the LID ordinance requirements. That doesn’t include projects that might have been submitted through the city’s Development Services Department, such as individual rain gardens or projects that aren’t related to new development.
Most developers assume these rules won’t be voluntary forever.
For one, the Environmental Protection Agency is increasingly pushing cities to control the quality of their stormwater runoff, Dawson said.
As the city changes, and there are more redevelopments, such as those at the Pearl and Lone Star breweries, Dawson expects that more LID projects will start to appear.
But for the development community to adopt the idea on a widespread basis, the LID rules “will have to have more teeth and become more mandatory,” he said.
LID continues to be studied. Last year, voters approved reauthorization of a sales tax for the city’s aquifer protection and linear parks. As part of that, $10 million was set aside for the first time to study LID projects over the aquifer recharge and contributing zones.
The city will take two of the demonstration projects to the City Council for approval early next year, said Grant Ellis, the parks department’s natural resources manager.
For the past two years, SARA has offered incentives for LID features. Private developers, as well as public entities, are eligible for reimbursements between $15,000 and $100,000 for construction costs.
Last fiscal year, SARA gave out $345,000; this year, the agency is on track to pay $520,000 in reimbursements by the time the application period ends in January.
“This is an attempt to help developers transition into this new style of construction and understand what the costs are and help offset some of that, help in the learning process,” said Jake Aalfs, a landscape architect for the river authority.
SARA also offers a $22,000 grant program to schools with kindergarten through 12 grades in Bexar, Wilson, Karnes and Goliad counties to fund on-site stormwater management features.
The river authority is working with the city to tack on LID features to any of the drainage projects currently slated for the 2017 bond, which voters will consider in May, Graham said.
The city is doing its part to incorporate natural elements when possible. Among the drainage bond projects being considered is a plan to improve Panther Springs Creek off Blanco Road. The city plans to keep the existing natural channel as part of the new water conveyance system.
“The old way to have done that project would have been a concrete ditch,” Graham said.
As part of a 10-year, $500 million flood control program, Bexar County developed an Ecological Assessment Protocol to identify and try to preserve natural resources, such as heritage trees, endangered species habitat and karst features, when planning and building its drainage projects. Engineers working with the county try to incorporate natural channel design when they can.
“If, within my flood control project, I can incorporate some water quality benefit within reason, then we do it,” said David Wegmann, Bexar County engineering services manager, who’s overseen the county’s flood control program.
LID has been incorporated into major street projects funded by previous bonds, such as Hausman Road and Ray Ellison Drive. SARA is retrofitting its headquarters in Southtown to include LID features, such as bioretention units and a permeable pavement parking lot. It is also adding rain cisterns at its Euclid office, where there’s already a rain garden.
It’s those kinds of publicly funded projects that are likely to convince the development community of LID’s benefits.
“I think before we see it from private industry clients, we will have to see it from public developments,” UTSA’s Elnakat said.
Even if LID rules become mandatory, it will be years before there’s a large, measurable effect in a city as developed as this one, said Dawson of Pape-Dawson Engineers.
“You’re not going to change stormwater quality overnight with one low-impact development or 10 low-impact developments or 10,000 acres of low-impact development when we have 700,000 acres of Bexar County,” Dawson said. “It will take a next generation of development before we can look back and say because we approached future development with low-impact criteria that it will make a difference.”
bgibbons@express-news.net
vdavila@express-news.net
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