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Shoal Creek Landslide Repair Image

Superior Knowledge of Local Conditions and Good Planning Solved Problem with Little Impact on Historic Neighborhood

Project Background

Shoal Creek Emergency Landslide Repair

After an emergency slope failure caused a landslide impinging on the residential backyards of an “Old West Austin” historic neighborhood and a heavily used Creekside trail, HVJ was asked to perform field investigation and laboratory testing to provide the information needed to design stabilization.

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Practice: Geotechnical Engineering

Sector: Water, Parks

Location: Austin, Texas

Services: Field Investigation, Laboratory Testing

Shoalcreek landslide from below slide

The Problem

In addition to an emergency issue with public concern, site access was a challenge because of very tight roads in the historic neighborhood and very soft unstable soil within Shoal Creek Greenbelt Park. HVJ had to acquire additional permits and coordinate with the City of Austin for large diameter branch clearing and piezo well installation at a very close distance from existing water and wastewater lines.

The Goal

  • To provide accurate geotechnical data of the project area on an expedited schedule
  • To provide services in an environmentally sensitive area and within the City of Austin protocol
  • Provide a stable, long-term solution
  • Perform services with minimal disturbance to the Old West Austin neighborhood in terms of traffic and protection of old-growth trees.

Our Solution

The client, GeoStabilization International, was particular about specialized testing, sample treatment, and environmental impact on drilling locations.  HVJ followed their instructions as requested. Special Pitcher Samplers were sought to achieve the highest possible core recovery in the fragile Del Rio formation. However, our local experience with skilled drillers proved that seldom-used HQ coring would provide even better results than Pitcher Samplers.

City project managers and members from Watershed, Public Works, Development Services, and Right of Way were heavily involved in our preliminary site visits. We worked with these groups to coordinate access, create a schedule, and approved procedures. Examples include the use of silt fences, geotextile socks (sediment logs), and Geofabric (Tridike) under the rigs to prevent drilling fluid contamination into the creek or storm drains.

Custom traffic control plans were required to allow drilling operations on the narrow residential streets with large, dense branch coverage from protected old-growth trees, with minimal disturbance to the Old West Austin's regular neighborhood traffic.

The site was cleaned and restored to conditions equivalent or better then what they were before the investigation. At the park, we utilized mats to prevent rutting and carted away all cuttings, fluid, and even dead branches that were at the drilling sites.  At the neighborhood roads, we used the same caravan of disposal tank vehicles to cart away material from the neighborhood and scrub the street clean of any evidence of our operations.  The flush mount manhole cover that we used for the piezometer well was smaller than usual and slightly matched the color of existing asphalt so as not to leave an impact.

The Result

  • Drilling operations, traffic control, and coordination of spoils disposal were complex, but HVJ made it seem like this emergency action investigation was just as smooth and easy as any small, quick project.
  • The project ran so smoothly and effectively that impact of field investigation was not noticeable to the Shoal Creek Greenbelt Park or the neighborhood.
  • A solution was reached to prevent future slope failure.

The project team was very good to work with, had excellent communication and got everything done on time.”

Christopher D. Calhoun, PE
GeoStabilization International (GSI)
Regional Engineer, South Central Division

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