Officials in West Lake Hills and Rollingwood have identified areas in their respective cities that are prone to flooding when it rains.

Discussions on a citywide drainage study began in West Lake Hills in 2014, and City Council contracted with K. Friese & Associates in May 2015 to identify current conditions and present short-term and long-term solutions to any drainage concerns, including how much each solution would likely cost.

In Rollingwood, city staff is creating a drainage manual for builders and identifying potential drainage projects. Both cities hope to address some of the solutions in the coming months.

West Lake Hills projects

Drainage study results were presented to City Council on April 13, and the drainage projects in need of greater attention were divided into categories.

“Our timing could not have been better,” Mayor Linda Anthony said, referencing several years of drought the area experienced before the recent heavy rains.

Travis Kaatz, a water resources engineer in training, said he and K. Friese & Associates Vice President Charlotte Gilpin met with city staff last fall to discuss drainage problems in the city and then visited many of the problematic sites to capture data such as pipe size, erosion, water running over the water and sedimentation.

The firm then developed a public survey asking residents to identify areas where they experienced flooding and other drainage issues both on private properties and citywide. It received 164 survey responses, Kaatz said.

The firm identified 55 areas of interest in the city that could potentially become projects, categorized each of them by type and suggested establishing prioritization categories such as risk to public safety, potential damage to infrastructure, recurring maintenance, public awareness and acquisition of rights of way.

Around Camp Craft Road in particular, Kaatz said the firm identified three areas of interest: one at the crossing of Eanes Creek and Eanes School Road, where water frequently goes over the road and causes erosion; one at the crossing of Eanes Creek and Camp Craft, which Kaatz identified as a low-water crossing road with heavy overtopping and heavy erosion; and one a little farther south on Camp Craft, where overtopping and erosion was also an issue. [polldaddy poll=9414614]

Kaatz said a third of the 55 identified areas were categorized as “roadway cross drainage,” referring to bridge crossings and culvert crossings that overflow; another third were categorized as “roadway parallel drainage,” or roadside ditches that are under capacity; and the rest fell into various categories such as erosion and local flooding.

Code revisions

K. Friese & Associates also reviewed the city’s code and found drainage language scattered throughout the text. Gilpin recommended removing the language and placing it in one section to address drainage policies.

“This is a really key component, because your code is your tool that staff has in order to head off future problems and manage and mitigate in the future,” she said.

Gilpin also recommended creating a separate document—a drainage and environmental design manual—to address design requirements and drainage criteria.

The next steps for City Council and staff include prioritizing the identified drainage issues and deciding which issues should be addressed.

Gilpin suggested the city also compare neighboring localities’ development codes and hold workshops with city staff to draft the drainage code and accompanying manual.

Anthony said the public will also be able to review the drainage plan draft and contribute comments once the firm recommends how to address the high-priority items.

“I think given what we’ve seen happening in construction projects throughout the city points to the need to have this sort of thing, because the problems are going to continue to occur and get worse, and I think we do need to update our code,” she said. “I hope that council will approve going down that road.”

Drainage manual

Rollingwood’s drainage issues are twofold: The city’s engineering staff has been working on an drainage manual that would list required criteria for homebuilders, and Mayor Thom Farrell has a list of street drainage issues he wants resolved.

Creating a drainage manual first came up in July 2015, when a drainage subcommittee was formed through the city’s planning and zoning and its utilities commissions, City Engineer Jay Campbell said.

When a resident in Rollingwood wants to build or expand a home, the city requires homebuilders to submit a drainage plan without any established criteria, and it is up to the city engineer’s discretion to approve the site after analyzing where water will drain, Campbell said.

The city engineers have drafted a manual and are awaiting comments from the planning and zoning and utilities commissions before bringing the draft to City Council for approval.

Campbell said when a drainage plan is submitted, the homebuilder and engineer must ensure excess rainwater does not run into a neighbor’s yard. If that is the case, the homeowner must purchase and install a storage tank—which city engineers say costs around $50,000—on their property so water can be gradually discharged at a steady rate.

“You build detention and then you capture that first rush of water, and then you meter it out slowly so that the downstream neighbor sees the same flow rate that he always saw pre-development,” City Engineer Marcus Naiser said.

City staff said they regularly receive complaints from residents who say their neighbors’ rainwater is draining into their yards.

Farrell said he estimates 50 or 60 properties in Rollingwood are currently being remodeled or completely rebuilt and points to construction as the cause of much of the drainage issues occurring on private property.

Citywide drainage system

At Rollingwood’s March 16 City Council meeting, Council Member Joe Basham asked whether a citywide drainage system is feasible.

Basham said his suggestion would involve digging underground and installing a drainage system, which would collect water in a large retention pond. Pollutants would then be filtered out so the water would eventually drain into Eanes Creek or Lady Bird Lake, he said.

Rather than requiring residents to spend $50,000 on a retention pond or storage tank, the city could spend about $20 million on a citywide drainage system, Basham said.

“That would be a monumental undertaking,” Farrell said. “It would change the character of Rollingwood.”

He said longtime residents have been able to address drainage issues through landscaping features, and newer residents who moved in during the drought made changes to their land and homes and “are now having to figure out what the older residents figured out a long time ago.”

Rollingwood projects

In the meantime, Farrell said he has a list of projects he would like addressed where flooding is prominent, including on Hatley Drive between Riley and Inwood roads; at Inwood and Rollingwood Drive; at Hubbard Circle; on Nixon Drive next to City Hall; and at Gentry and Sugar Creek drives.

Solutions include installing valley gutters and enlarging drains and culverts, Farrell said.

“We’re trying to keep the water out of the streets and flowing to where it’s supposed to go,” he said.

He has tasked city engineers with performing a preliminary study on those areas and said he hopes to begin work on the projects in the coming months after reallocating the budget.

“We’re committed to doing this in a fiscally responsible way,” he said. “We’re working really hard to make sure that these are permanent solutions.”