Purgatory Creek project aims to mitigate flooding

A project that would put at least 90 structures out of the floodplain got the city council’s informal go-ahead Tuesday night.

Project Engineer John Espinoza and Director of Engineering and Capital Improvements Laurie Moyer gave a presentation on the Purgatory Creek Capital Improvements Project. The presentation was meant to determine if city staff should move forward with the plan, which is not funded yet but is in the city’s long-term Capital Improvement Program. 

“We understand funding challenges are the outstanding issue and we are working on that,” Moyer said. “... We’re here tonight to make sure that we’re on track with what you’d like to see.”

Espinoza gave the presentation on the Purgatory Creek project, which has just gone through the preliminary engineering phase. 

“The primary goal is flood mitigation,” Espinoza said, adding that the city will take “a holistic approach” to the project that also takes into account improved public spaces and water quality. 

Phase 1 of the project will run from Johnson Avenue to the San Marcos River, Espinoza said. Phase 2 will run from Wonder World Drive to Johnson. 

For Phase 1, Espinoza said, the creek will have a 140-foot bottom width with varying slopes along the channel sides. The project will also include tree preservation and riparian grow zones to help with water quality, as well as trail considerations.

“We talked a lot about this,” Espinoza said of the potential trails. “... Right now what we have is just a conceptual idea.”

The trails are intended to provide access to streets, other trails and the river, with an eye to accessibility and safety. 

The project will also include utility and wastewater upgrades and drainage improvements and a channel diversion for the creek’s outfall into the San Marcos River during high water flows. All in all, Espinoza said, after the project’s completion, more than 90 structures currently in the floodplain will be out of the floodplain.

Permitting for the project will involve working with the U.S. Army Corps of Engineers, the Texas Historical Commission, Union Pacific, the Texas Parks and Wildlife Department and other agencies, Espinoza said. The anticipated cost of the project is $23 million for Phase 1 and $21 million for Phase 2.

Though no formal vote was taken, the council expressed its approval of the project and urged staff to continue with it. The city’s proposed 2020 Capital Improvement Program includes design funds in 2020 and construction funding for Phase 1 in 2022. 

However, the agenda stated, “The Purgatory Creek project is significant in scope and cost; staff will be investigating options to supplement city funds as well as phasing options to meet city funding limitations.”