Slope Stabilization

Patapsco River Bank Stabilization

Restoration in process

Ellicott City, MD

Client: Plexus Scientific Corporation

Plexus Scientific of Columbia, Maryland was retained by the U. S. Army Corps of Engineers to remove contaminated soils from an abandoned industrial site immediately adjacent to the Patapsco River.Ā  Remedial excavation eventually extended to the river’s edge, and Plexus was required to submit a comprehensive restoration plan that would provide a stable bank that blended well with the rural setting. ARM Group, Inc. was retained to evaluate site conditions and prepare a restoration plan meeting the Corps of Engineers requirements.

Design of stabilization measures was complicated by the steepness of the river bank, which was at a slope of 1.6H to 1V through the restoration area. The restored slope also had to withstand flood flow velocities of up to 15 feet per second. ARM reviewed available boring information and sampled proposed backfill soils to determine their strength properties relative to analyzing the stability of various slope configurations. ARM designed a slope incorporating layers of polymer grid reinforcement that allowed the steep slope to be built from locally available soils, while still providing acceptable long term stability. A rip rap toe berm was incorporated into the slope to enhance stability and erosion resistance along the slope portion subject to the most frequent high velocity flows. The remainder of the slope face was covered with an erosion resistant organic netting to protect the slope until vegetation was established. Saplings were also planted on the face to help stabilize the slope and to blend the restored section into the wooded river banks on either side. The proposed restoration design was reviewed and approved by the Baltimore District of the Corps of Engineers.

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