Attention Neighbors, Trail and Park users and Friends of Balcones Park
We have an urgent plea for your assistance!
You may have noticed the shoddy state of the most recent section of the Northern Walnut Creek Trail in Balcones Park between Amherst and the ballfield by Scribe Drive. After months of delay, the city has announced that they will be performing limited repairs beginning 9/30/19 as follows:
1-addressing erosion & drainage issues,
2-cracked slabs and portions of the trail that have been undermined,
3- runoff issues at Scribe Drive.
MNA has pressed the city repeatedly to provide clarification regarding fixing specific design defects that have led to gravel eroding from the side of the trail and washing onto the pavement and into the creek. This problem results from two design deficiencies
Firstly, the city decided to use “Flex Base” (crushed limestone -see below for a technical discussion and further explanation) to backfill the edge of the concrete path. This material is not erosion resistant and water flowing off the concrete path erodes the material and washes it out of the side of the trail, leaving large drop-offs in some areas. In other areas it washes onto the trail creating a hazard to trail users. Additionally, much of the eroded material washes off the trail and into the nearby creeks. The city has indicated that they will only replace the areas of flex base that have completely failed, despite the fact that other areas are showing signs of impending failure and that along most of the trail, runoff has eroded the surface layer from the flex base, leaving a loose gravel surface. Even during months of drought, this loose material gets tracked onto the pavement creating a slipping hazard for foot traffic and skidding hazard for cyclists.
Secondly, the design of the sidewalk ramp at Scribe Drive was designed so that it allows water to escape the street drainage system, cross the sidewalk and flow down the trail instead of directing water to a curb inlet. The City initially did not want to fix this but after is was pointed out that city standards specifically prohibit runoff leaving street drainage and flowing across and down as sidewalk, they finally agreed to remove and replace the ramp. [link to email to City][link to MNA analysis sent to city]
This brings us back to the flex base issue. Flex base is used primarily in street construction beneath the asphalt or concrete pavement. It works well for this purpose as it compacts to a very stable state and provides good support to the pavement, as long as excessive moisture does not penetrate the flex base. MNA first heard that the project manager intended to require flex base along the trail in October 2018 when MNA asked the city to revisit how the trail would connect to the existing trail completed in Dec. 2017. Public Works employees Larry Mendez and Josh Oeffinger told us that flex base was the new standard for trail projects, and that the plans required it. We were assured “it will wear like iron”. In fact, the project plans and specifications call for “select fill”, but does not specifically require flex base [City of Austin standard specification 130S-Borrow]. We pointed out that flex base has insufficient organic material content and and lacks the moisture retention capacity needed to sustain vegetation. We requested that soil, protected with erosion control matting be used instead of flex base which could have been done at little or no cost as flex base is more expensive than soil. The plans already called for erosion control blanket in most of the erosion prone areas of the site. (link to 9/28/19 memo)
Despite our request, the city directed the contractor to backfill the pavement with flex base. Very soon after, the installation was tested by a rainstorm. Large areas of flex base were washed off the pavement and into the creek, with large deposits left on the trail [link to photos]. We immediately shared this information with the city. This led to a series of meetings and email communications with the city. The city’s reaction was that this was not a big deal and saw no reason to correct any of the deficiencies! We reached out to other city departments including the office of the Chief Engineer, who shared with us a newly adopted trail standard – that does not have flex base, but topsoil for the pavement backfill! [City of Austin Standard Detail 1302S-1] We also found out that the City Environmental Board had insisted on this design due to erosion problems in other trail projects in the City [Austin Monitor 4-8-19]. We also found out that the City General Permit Program that has environmental oversight over the project likewise insisted that the flex base was not acceptable and directed project staff to replace the flex base with soil and vegetation [link to email from GPP to Public Works]. As we were continuing to meet and discuss the issues, the city poured a concrete swale along one section of the the trail to replace a section of eroding flex base. This fix has worked fairly well, except that it directs water across the trail. Again, water flowing in a concentrated manner across a sidewalk violates city standards, but we agreed to live with this as long as other areas of flex base that were showing signs of erosion would be replaced with soil.
Finally in April 2019 we had a reprieve – the city staff agreed to replace the flex base where it was eroding. The city asked us for our opinion on what areas needed to be replaced, which we sent to the city. During the next few months, we had several more rainstorms. With each storm, more flex base washed out from the side of the trail, onto the trail and into the creek [link to Dec. 29, 2018 photos] [link to April 7 2019 photos].
Despite the known deficiencies that were creating trail hazards, the city was completely indifferent to the trail conditions, meaning that it was up to trail users to report the hazards. [link to 6-17-19 email to project mgr] [link to 7-15-19 email to project mgr] When contacted, the city did send the contractor to clean it up, but gave no word on a permanent fix. In August, we noticed further displacement of the cracked pavement as well as shifting and cracking of flex base along the trail. [link to 8-21-19 email to project mgr] We asked again for the status of the permanent fix and were told the contractor was asking too much to do the repairs, (insisting on using hand labor to avoid damaging the pavement.) We pointed out to city staff that the contractor was very obviously using water trucks to water the trees and shrubs along the trail that were planted as part of the project (albeit only after neighbors noticed the trees were dying due to lack of water – see link to Dead Tree Page), and that sections of the trail that already cracked were the contractors responsibility to replace (and long overdue). Soon after we were told that an agreement had been reached with the contractor, and that the work was just waiting to be scheduled. We then requested clarification on what areas were to be repaired and found that our list had been redlined by city staff and that only 3 areas of the worst erosion were to be replaced. [link to redline of repair areas] We protested strongly and pointed out areas where the embankment was improperly graded and why the flex base was expected to fail. We also pointed out areas of concrete cracking beyond the areas identified in April. We requested a meeting with the City to discuss further. On 9/17/19 we got our answer
“After extensive conversations with the Parks and Recreation Department, our engineers as well as maintenance staff, some areas you recommended for base removal and revegetation have not been included in the scope of work. The main reasons for this are because we have observed vegetation growth in these areas and do not want to disturb what has started to take root. The seeds that have been planted are native seeds, and are perennials which won’t require reseeding. ”
Regarding additional pavement cracks beyond the area noted in April, the city responded that new cracks are superficial.
We responded with one final attempt to compromise – requesting the city to at least repair two more sections – one that is showing signs of impending failure and another area that needs repairs due to improper slope stabilization, and provide a commitment to fix the other areas that are not as likely to fail, but will continue to create hazards by bleeding gravel onto the trails erosion by next summer. We also pointed out our disagreement regarding the cracked pavement and requested clarification on what the city would actually replace. No response has been received.
We also requested the project management supervisor and office of the engineer review this decision [link to 9/18/19 memo]. We have not heard from the city staff, office of the chief engineer; the project manager supervisor blithely requested that we continue to communicate with the project team (and has not returned phone calls to discuss the engineering basis for our requests.)
At this point we are faced with the prospect of continued failure of the flex base, further hazards to trail users, as well as continued migration of sediment to the nearby creek. No other sections of the trail have this flex base lining the trails. The use of flex base clearly is is a failed experiment. See this link for site photos and video of trail conditions as of 9/18/19.
After nearly 10 years of disruption to Balcones Park we feel it is time to for the city to step up and properly restore our beloved park [link to project timeline]. The City audited the Capital Improvements “Project Delivery” process in 2017 and this project has been a case study in how badly the system is working [link to audit].
If you want to see the park properly restored, please take a few minutes to call and email the following
City Council, Leslie Pool http://www.austintexas.gov/email/district7
City Manager, Spencer Cronk Phone: 512-974-2200
Public Works Director, Richard Mendoza – email@example.com, Phone: 512-974-7065
Parks and Recreation Board Director, Kimberly McNeeley – Kimberly.McNeeley@austintexas.gov, Phone: 512-974-6700
Watershed Protection Department, Office of the Director: 512-974-2501
City Environmental Commission
bc-Peggy.Maceo@austintexas.gov; BC-Curtis.Smith@austintexas.gov, BC-Katie.Coyne@austintexas.gov; BC-Wendy.Gordon@austintexas.gov, bc-MaryAnn.Neely@austintexas.gov; bc-Andrew.Creel@austintexas.gov, BC-Kevin.Ramberg@austintexas.gov; BC-Perry.Bedford@austintexas.gov, bc-Pam.Thompson@austintexas.gov; firstname.lastname@example.org
City Urban Transportation Commission
City Parks & Recreation Commission
City Urban Forestry Commission -awaiting contact information
City Bicycle Advisory Council- awaiting contact info
Please ask for
- removal of all flex base from the sides of trail and be replacement with soil and vegetation, protected with erosion control blanket and given sufficient watering to ensure vegetation growth.
- Replacement of all the cracked sidewalk sections that have any crack separation
- Replacement of all dead trees and shrubs before winter dormancy
- Weekly updates on the progress to achieving these items.
suggested Subject line: REPLACE THE BASE! BALCONES PARK
Please also pass on this information to any friends, family, etc.
Final thoughts: this is our last chance to get this done. If we do not succeed, we will be having to beg for the city to come repair the erosion and cracked pavement. The city has a huge backlog of maintenance and our request will go to the bottom of the list. Our park already suffers from lack of maintenance. Broken irrigation system at the pool requires volunteers to bring hoses to the park to water plants, volunteers already clear the trails when trees block the trail, trim branches, clear gravel and pick up trash. We had to secure a grant to repair the “Creekside Trail” in the park (and contributed cash and volunteer labor as part of the grant). If the city is so careless with our dollars to allow over $20,000 worth of trees to die [link to Dead Tree Page], they surely can find money to finish this project properly.
Design of the project actually started in 2002. Construction started in Balcones Park in 2010. See below for previous media coverage of the Northern Walnut Creek Trail failings