Parks staff mark completion of first phase of Walnut Creek trail project

The city has brought to a close all major work on the portion of the Walnut Creek Hike and Bike Trail that runs through Balcones District Park, located to the west of MoPac Expressway. In a presentation to the Parks and Recreation Board last week, staff from the Parks and Recreation and Public Works departments detailed the many stops and starts that went into completing the section of the larger trail project that started construction in 2010.

The westernmost section has in recent years become known in PARD shorthand as “phase 1A” because it had to be broken off from the rest of the three-mile trail project due to difficult landscape engineering issues and its connection to a larger Austin Water wastewater project. Construction work on phase 1A concluded in late 2018 and late last year the department performed a one-year warranty checklist with the contractor that found several problem areas that needed to be corrected.

Those issues included sections of cracked pavement throughout the 10-foot trail, recently planted trees that were in poor health due to inadequate watering and a severely hot summer, and excessive erosion and drainage problems along a ramp located near Scribe Drive.

Ana Seivert, a project coordinator for the Public Works Department, said the contractor and at least one subcontractor on the project were difficult to contact about issues discovered by staff and residents in the nearby Milwood neighborhood, which added to the time needed to replace the concrete sections and address the other issues.

“We’ve learned some valuable lessons from this, for sure,” she said. “We thought that putting trees in an existing park where they’d be accessible for contractors to water and keep healthy would be relatively easy for the contractor to do that … that was not the case. The contractor was not reliable and was very difficult in getting them to respond.”

Seivert said part of the drainage issue and erosion along Scribe Drive was caused by the installation of a curb ramp that allowed water from the street to run onto the trail and erode one-foot compacted gravel shoulders for a short section along the trail. The curb ramp has since been replaced and the shoulders that had erosion those have been replaced with soil and native vegetation that has started to flourish and reduce the runoff.

Board Member Francoise Luca said the drainage problem was compounding along the creek and creating water quality issues downstream in Gracywoods Neighborhood Park and Walnut Creek Metropolitan Park.

“One of the concerns we have is on these shoulders and the runoff from the gravel, it’s going into Walnut Creek and so what’s happening is that the water quality at Gracywoods is failing or is being compromised by the silt of that material running into the creek,” she said. “If we don’t address it in Balcones Park we’re just pushing the problem into Gracywoods Park.”

The rest of the first phase of the trail – located east of MoPac and running through Walnut Creek Metropolitan Park – was completed in 2017, though at times it too faced problems including concerns from neighbors. The second phase that will extend the trail to Interstate 35 is listed as “Active” but not under construction on the city’s capital project explorer portal.

Board Chair Dawn Lewis said she and other stakeholders noticed some steep drop-offs caused by erosion along the trail, including one near a ramp entrance, that presented clear safety issues. Her questions about replacing the eroded ground prompted Public Works project manager Larry Mendez to respond that the more important step is removing the features that are causing the erosion, such as the gravel shoulders, and planting native vegetation.

“At one point we were looking at the question of if we are going to replace all of the base material and put soil back in there,” he said. “Now if there is an erosion problem or a drainage problem, whatever you put in there is going to erode until the vegetation gets established.”

This story has been changed since publication to clarify the role of the Public Works Department on this project, and the nature of the erosion on the trail. Photo courtesy of the city of Austin.

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