As part of the engineering and permit work for the development of the 70-acre Airport Center, Hanover Engineering completed the design and permitting of on-site compensatory mitigation for the stream and riparian corridor impacts associated with construction of the shopping center. The commercial center is located along Route 22 and Airport Road in Hanover Township, Lehigh County, Pennsylvania. The primary goal of the 5.4-acre on-site mitigation project was to restore wildlife habitat lost due to impacts to the on-site riparian areas from construction of the Airport Center. This was accomplished by creating a single large contiguous area of terrestrial riparian habitat. A secondary goal of the project was to stabilize the severely eroding stream channel flowing through the site and mitigation area.
The grading plan for the riparian mitigation area included construction of a meandering rock-lined channel with broad floodplain, designed to convey high storm runoff volumes and velocities through the site from existing upslope, off-site development, as well as controlled discharges from the Airport Center facilities.
The planting plan was developed using a combination of native seeds, shrubs, and trees in an effort to re-establish natural conditions to benefit local wildlife. A total of 128 trees and 483 shrubs were planted throughout the mitigation area in an effort to establish a base cover. Infill by volunteer shrubs and trees from local seed sources was used to complete long-term coverage of the site. A deed restriction was established for the mitigation area to prevent future development and other impacts. Hanover Engineering is currently monitoring the site to document conditions and to ensure proper establishment.