Letchworth State Park – Gibsonville Culvert

NYS Parks called upon the Erdman Anthony team to provide schematic design, design development and construction document preparation for this project, which addressed:

  • A deteriorating 90 inch-diameter corrugated metal pipe;
  • A segment of failing (sliding) roadway embankment downstream of the 90-inch culvert;
  • Asphalt pavement reconstruction to restore roadway integrity and ride quality.

The project is located in Letchworth State Park, along Park Road (also known as Mount Morris Road), approximately 0.25 miles south of its intersection with Gibsonville Road in the Town of Leicester, New York.

The subject stream is an un-named "blue-line" stream that is tributary to Silver Lake Outlet. A 520 foot portion of this stream was conveyed through a deteriorating 90-inch corrugated metal pipe culvert located at the toe of a long steep natural slope supporting Park Road. The culvert was installed in 1976 as a key element in a slope stabilization project to buttress an existing slope. Approximately 400 feet downstream of the 90-inch culvert, the Park Road embankment, at its intercept with the unnamed stream, had become destabilized and was slipping, causing a very noticeable settlement in the Park Road roadway grade. There was over 30 feet of vertical fall in the stream channel along the length of the project, including the portion carried by the culvert.

The final project design permitted by the NYS DEC and the U.S. Army Corps of Engineers restored the open stream channel by filling and raising the stream. The existing culvert was left in place and filled with low-strength concrete. At the downstream end of the restoration and immediately upstream of Park Road, a series of drop structures constructed of grouted rip-rap (i.e., a man-made waterfall) dissipated erosive water flow energy and brought the stream channel back to existing grade. This was just upstream of the existing concrete box culvert that carries the stream under Park Road Stream restoration measures and techniques included log revetments, live stakings, tree plantings, installation of fiber rolls on steep slopes, and grading to create vernal pools in the restored stream's newly established floodplain area. Park Road restoration work included 400± feet of full depth reconstruction through the area of road subsidence, an additional 1,000± feet of roadway repair and rehabilitation, a new guide rail, and installation of transverse and longitudinal underdrains to intercept and convey sub-surface water in a controlled manner. A comprehensive Stormwater Pollution Prevention Plan (SWPPP) was also prepared to address the erosion and sediment control during the project’s construction. The project is now nearing construction completion and the restored stream is expected to be fully revegetated by the fall of 2015.

Project Accolades

  • Project Awards
  • 2016 Environmental Project of the Year Award in the less than $5 million category - APWA New York Genesee Valley Chapter
  • 2016 Diamond Award, Engineering Excellence - Waste and Storm Water Category, ACEC New York
  • Environmental Project of the Year - Award in the less than $5 million category, APWA New York State Chapter

Project Details


Castile, NY


NYS Office of Parks, Recreation and Historic Preservation

Project Contact

Marc Kenward, PE
  • Marc Kenward, PE
  • 585-427-8888 x 1012
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