Repairing Austin’s beleaguered drainage system will potentially save lives and properties in the city’s flood-prone areas, such as Onion Creek, Southwest Austin stakeholders say.
“In the 2015 flood, drainage pipes did more damage to homes in the upper Onion Creek neighborhood than the creek [did],” said Ken Jacob, vice president of the Onion Creek Homeowners Association and member of the city’s Flood Mitigation Task Force.
The city’s watershed protection department estimates about 100 of the 1,100 miles of storm drainage pipes in Austin are in need of replacement and upgrades.
“We suffer from flood amnesia,” Flood Mitigation Task Force secretary Carol Olewin said. “We are in a drought right now, so flooding is in back of mind. Then we get flash floods, and we are inundated with a system that has not been maintained.”
EMPHASIS ON DRAINAGE
In March 2016 the task force presented an executive summary to City Council describing the top priorities it identified as imperative in fixing the city’s flooding problem.
An emphasis was placed on repairing aging storm-pipe infrastructure, which members said was not designed to handle the additional runoff caused by population growth a
nd an increase in existing and future developments.
The summary recounted personal stories of loss and grief from residents who had experienced flooding caused by “overloaded storm drainage systems, poorly maintained drainage systems, increased impervious cover from development and poor drainage designs from the past.”
Their home badly damaged by the October 2015 flood, David and Liz Willson were offered a buyout by the city of Austin. At an Aug. 3 meeting, City Council authorized the designation of funds to purchase the Willsons’ home and nine other properties in the upper Onion Creek neighborhood determined to be most at risk for flooding.
The Willsons maintain the city’s development regulations, which limit the amount of stormwater runoff into the drainage system, are inadequate.
“There is no way a developer can do enough on his particular project to accommodate the scope of the flooding problem along Onion Creek,” David Willson said.
The task force also proposed a moratorium on all new development in the 100-year flood plain, or areas determined to have a 1 percent risk of flooding in any given year, until the watershed protection department’s ongoing Onion Creek Floodplain and Flood Mitigation Study is complete. That recommendation was not enforced by City Council.
THE IMPACT OF DEVELOPMENT
Members of the task force, the watershed protection department and City Council are advocating stricter impervious cover regulations be placed on developments in the final draft of CodeNEXT, the city’s overhaul of its land development code.
According to the watershed protection department, impervious cover, or manmade surfaces impenetrable by rainfall, places additional strain on the city’s drainage system by increasing the volume and speed of stormwater runoff.
To adhere to city regulations, developers must show that runoff from their property will not increase peak stormwater flow and cause adverse effects downstream. To do so they can provide a mitigation structure, such as a detention pond, or they can participate in the city’s Regional Stormwater Management Program, in which a developer pays a fee to the city to help pay for the planning, design and construction of regional drainage improvements, according to the watershed protection department.
Council member Ann Kitchen, whose district covers Onion Creek, said a developer’s contribution to drainage solutions should be based on the proposed development’s total impact on the city’s drainage system.
“What we have going with CodeNEXT is a change requiring both new developments and redevelopments contribute their fair share by providing both on- and off-site flood detention ponds and conveyance solutions proportional to the impact the development has on the system,” she said.
Jacob voiced particular concern over the 70-acre Cebolla Creek subdivision under construction in Austin’s extraterritorial jurisdiction near the intersection of Old San Antonio and Twin Creeks roads. Most of its drainage will flow directly into Onion Creek via a 10-square-foot pipe “big enough to drive a small car through,” he said.
“While there is some disagreement as to who will be impacted, the message is clear that there will be an additional impact on flooding downstream,” Jacob said.
Maintaining the pipes
Reem Zoun, supervising engineer with the city’s watershed protection department, said her staff addresses drainage issues based on a “worst first” criteria determined through video monitoring and 311 calls.
Repairing the infrastructure built prior to the adoption of the city’s drainage criteria manual in the mid-1970s, she said, would require resources the department does not presently have.
“Our storm drains are not sized large enough in some areas,” Zoun said. “That is what is expensive, and that is where we do not have the resources to address or upgrade all of our storm-drain systems.”
A backlog of 502 work orders is slowing the regular maintenance of closed storm drainage pipe infrastructure, the task force report said. The department is chipping away at those orders, many of which are minor, said Jose Guerrero, assistant director of the watershed protection department.
A NEED FOR FUNDING
Each year, the department allocates funding toward drainage pipeline management, which pays for the operating costs of cleaning, inspecting, and rehabilitating the pipes, as well as investigating drainage complaints and paying employees who work to repair the system.
The city’s drainage utility fee that appears on the monthly utility bills of Austin residents is what funds a portion of the watershed protection department. The fee is based on a property’s percentage and amount of impervious cover.
Due to an increase in impervious cover from new development, the watershed protection department’s budget is projected to increase by approximately 6 percent in fiscal year 2017-2018. Of that, $7.2 million will pay for drainage pipeline management.
The flood-mitigation task force contends that the drainage utility fee is not sufficient in funding major capital improvement projects. Instead members say those projects should be funded through bonds, which has not been done since 2006.
“As long as the department is depending on the drainage utility fund to cover budgetary requirements, anything big needs to go through bonds because, if not, you are robbing Peter to pay Paul,” Jacob said.
Anupa Gharpurey, financial manager of the watershed protection department, said a bond would not be sufficient in fully addressing the department’s exorbitant capital improvement project needs.
“Our capital improvement project needs can be supplemented through bond funding, but our need for drainage utility fee funding is not going away anytime soon,” she said.
Kitchen said she is supportive of a bond to fund drainage improvements.
“I think we will have to [pursue a bond],” she said. “There is no way we can keep up with these needs given the status of our storm pipes.”
In early August a group tasked with reviewing requests and making recommendations related to drainage infrastructure improvements to the city’s 2018 bond advisory committee was formed by City Council.