Explanation of Significant Differences for the Marsh Run Park New Cumberland Army Depot Formerly Used Defense Site

Published March 7, 2014
Expiration date: 4/30/2014

The U.S. Army Corps of Engineers (USACE) is issuing this notice to present their plans for completing remediation of the former New Cumberland Army Depot landfill located at Marsh Run Park.  Pursuant to the Record of Decision (ROD) issued by the Pennsylvania Department of Environmental Protection (PADEP) in 1991, the USACE designed and installed a groundwater pump and treat system and a soil vacuum extraction system to remediate the site.  In late 1996, the groundwater pump and treat system was removed from service due to a fire.  In 1999, the remedy was modified by the first Explanation of Significant Differences (ESD) to utilize monitored natural attenuation and enhanced soil vapor extraction.  The enhanced soil vapor extraction system operated for approximately 2.5 years and removed an estimated 225 pounds of contamination before it was shut down because it had reached its limit of effectiveness. 

Now that the treatment activities have ended, the USACE plans to utilize natural attenuation and land use controls to continue to prevent exposures to the onsite landfill material, subsurface soil, and groundwater, and to restrict the potential offsite use of groundwater where it may contain concentrations above drinking water standards.  The table below illustrates the significant differences between the original remedy presented in the ROD, and the subsequent modifications:









Treatment Streams


Soil Vapor, Groundwater


Soil Vapor, Groundwater


(Treatment Completed)

Soil Vapor Treatment



Soil Vapor Extraction

Enhanced Soil Vapor




Soil Vapor Treatment



1 year


2 years




Geosynthetic Cap


None Present


Placed over Source Area

No longer needed since Soil Vapor Treatment complete.

Extracted Groundwater

Treatment Method

Air Stripping plus Activated


Air Stripping plus Activated



Treatment Completed

Design Approach: Soil Vapor

Source Treatment

(landfill area)

Source Treatment

(landfill area)

Source Treatment (Completed), Institutional (Land Use) Controls

Design Approach: Groundwater



Monitored Natural Attenuation

Monitored Natural Attenuation (modified monitoring and frequency) and Institutional (Land Use) Controls

The implementation of additional land use controls, the modified remedy will be protective of both human health and the environment, will meet the Remedial Action Objectives and Federal and State requirements, and is cost-effective.  In addition, the site remediation has utilized permanent solutions and alternative treatment technologies to the maximum extent practical.

The administrative record file for the site, which contains the ESD and all documents that formed the basis for the site remediation, are available for public review at the locations listed below.  Questions may be directed to Ms. Liza Finley at (410) 962-2683.

New Cumberland Public Library                       Fairview Township Municipal Building

1 Benjamin Plaza                                              599 Lewisberry Road

New Cumberland, PA 17070                             New Cumberland, PA 17070