South Fayette Landslide Repaired with Low Volume Road Grant Funds
Coal Pit Run Project to Reduce Runoff to Chartiers Creek
With increased rainfall over the last two years, landslides have become significantly more common in the Western PA region. The Dirt, Gravel and Low Volume Road (DGLVR) Grant Program distributes funds to remedy runoff and erosion on unpaved or low volume roads, helping prevent landslides and preserve the integrity of Pennsylvania watersheds.
In 2018, $373,000 was allocated to the Allegheny County Conservation District for grant administration, project funds, and grant oversight. Out of eleven applications, six projects were awarded funding: four projects through the LVR funds and two through the DGR funds.
One of these projects was Coal Pit Run Road in South Fayette Township. The township applied for funding due to a significant landslide that was impacting the road on a very steep slope. Grant funds were awarded to repair the slide and construct a Geosynthetic Reinforced Soil (GRS) Wall to solve the stabilization problem.
The topography of the region generally consists of shale layered with clay, creating a very slippery surface when soil is saturated. Traditional road practices to stabilize a steep slope like the one that is present on Coal Pit Run Road tend to be extremely expensive, albeit very effective. A GRS Wall is a relatively new method that is less expensive and has a similar expected lifespan as other more traditional practices. It consists of compacted gravel fill layered with geosynthetic reinforcement materials, such as a fabric (geotextiles) or polypropylene mesh (geogrids). This creates a fill material that is significantly more stable than the clay/shale mixture.
In addition to the GRS Wall, the township installed 4 concrete inlets and 1220 linear feet of pipe to convey drainage away from the road surface and prevent future sedimentation and erosion. The worksite was stabilized with topsoil, seed, and mulch to create root mats to further stabilize the hillside.
The entire project was completed in October 2018 for $225,000, which was about $15,000 less than budgeted; the township contributed $60,000 to this total as in-kind work. This new method helped reduce the amount of sediment entering Coal Pit Run, which flows into nearby Chartiers Creek, while stabilizing the road surface for local residents. The project turned out picture-perfect and is a great reference point for future landslide repair around the county.
The landslide on Coal Pit Run prior to project funding
Coal Pit Run after project completion