This project involved topographic survey of three specific areas in the park to develop design mapping for the improvement of the Gorge Trail. These areas had been classified as safety hazards due to erosion over time. Each area varied in size from less than an acre to over 3 acres, with the total project totaling approximately 5 acres in size.

For one area, Erdman Anthony completed a detailed topographic survey of historic stone steps. built by the Civilian Conservation Corps in the early 1930s. The slope that the steps were built upon was showing signs of instability and the steps were beginning to slide into the gorge. Conventional topographic survey methods and 3-D laser imaging were employed to accurately capture the historic steps and measure the magnitude of tilt into the gorge.

The second area was the overlook area at the Middle Falls. This topographic survey included stone walls and a walkway built by the CCC that were above and immediately adjacent to the 100-ft high Genesee River Falls. Three-dimensional laser imaging was used to capture digital data required to generate the digital terrain model surface documenting existing conditions of the eroding rock face located at the base of the falls. Use of the laser imaging showed that the overlook area was cantilevered out over the gorge by more than 10 feet.

The third area was a trail switchback that was eroding from poor drainage conditions. The conventional topographic survey was performed in this area detailed the break lines and features to aid in the design of a new drainage system for the area. The planimetric mapping and DTM were delivered in ACAD2000 format conforming to the NYS Parks' CADD specifications. A survey report was prepared and delivered to the client for future establishment of the survey control for construction purposes.

The combination of conventional topographic survey methods and 3-D laser imaging allowed the project to be completed under the proposed budget and in an accelerated time frame. Mapping the gorge walls accurately was of key importance to avoid any possibility of future disaster. 

Click here to read an article on this project published in "Government Engineering Magazine."