Harrisburg International Airport Obstruction Removal Project

Tree growth at the Sunset Golf Course adjacent to the Harrisburg International Airport owned and operated by the Susquehanna Area Regional Airport Authority (SARAA) was found to obstruct runways and the FAA required that trees be removed to increase safety for approaches and departures from Runway 13-31. The challenge for this effort was that the Sunset Golf Course is a municipal facility owned by Londonderry Township and therefore considered a Department of Transportation (DOT) Section 4(f) Resource, which required that a DOT Section 4(f) Report be completed and coordinated through the FAA and the Department of Interior (DOI). The tree removal would also cause ground disturbance such that it was necessary to prepare an Erosion and Sedimentation Control Plan, as well as obtain a National Pollutant Discharge Elimination System (NPDES) permit.

Rhea was tasked by Michael Baker International as a service to SARAA to prepare the Section 4(f) report, prepare the Erosion and Sedimentation Control Plan, the NPDES permit, and design stormwater controls consistent with the Pennsylvania Best Management Practices (BMPs) Manual and in compliance with the required technical criteria outlined in the Dauphin County Act 167 Stormwater Management Plan and the Londonderry Township Stormwater Management Ordinance.

The Harrisburg International Airport (MDT) is an 800-acre property located in Lower Swatara Township, Dauphin County, Pennsylvania. MDT is the primary air carrier airport serving Harrisburg, the capital city of Pennsylvania, and the central Pennsylvania region.

The stormwater solution developed for the project was based on the results of infiltration testing and stormwater analyses under various assumed flow conditions. Bioinfiltration/ Infiltration Trench (BIT) Best Management Practices (BMPs) were proposed and installed to offset the changes in runoff volume and rate due to the proposed disturbances. The NPDES permit boundary was 120.0 acres and the limits of disturbance boundary encompassed 30.3 acres. A result of putting a stormwater volume control BMP in one of the sub-watersheds allowed Londonderry Township to meet Municipal Separate Storm Sewer Program (MS4) requirements by posting educational signage near the location of the BMP.

In parallel, Rhea supported SARAA as it pursued a letter for Londonderry Township to execute a de minimis use finding. Support included providing information and graphics to support the strategy to obtain the de minimis letter. Ultimately the letter was acceptable to Londonderry Township and development of a final 4(f) Report was not required.

The efforts for this project were completed in compliance with FAA Order 5050.4B, National Environmental Policy Act (NEPA) Implementing Instructions for Airport Actions, FAA Order 1050.1E, Environmental Impacts: Policies and Procedures, and the Environmental Desk Reference for Airport Actions.

Services: Water Resources Engineering

Industries: Aviation