Project Description:
The Township of Derry proposes a comprehensive upgrade to their current stormwater system, in areas with historical flooding and erosion problems. The proposed project includes the design of an integrated storm sewer, sanitary sewer, open channel, and roadway culvert elements in three (3) distinct problem “areas” within Derry Township.
Area 3 – (“Cocoa Ave”) of the Stormwater Improvement Project is divided into two (2) phases.
Area 3, Phase 1 will be located mostly in areas east of Cocoa Avenue, just north of the intersection of Cocoa Avenue and Governor Road (S.R. 322) and to the south of this intersection, in a farm field along an established waterway with adjacent wetlands. In Area 3, Phase 1, improvements will include realigning a tributary of Spring Creek, installation of new earthen channels, and installation of new culverts. The improvements are designed to increase conveyance capacity and enhance water quality along Tributary 09510 of Spring Creek. New storm sewer is planned for installation along Cocoa Avenue to increase the rate of runoff capture from the ground surface, and increase conveyance capacity to the existing stormwater discharge.
The upstream extent of improvements to Area 3, Phase 1 is located on Cocoa Avenue between Governor Road and Fishburn Road. Rerouting Tributary 09510 of Spring Creek from the current location west of Cocoa Avenue, to the east side of Cocoa Avenue is proposed by way of installation of a new stream channel. This will also bring the stream channel back to its historical alignment. The existing channel west of Cocoa Avenue will be partially piped and continue to carry localized stormwater to the relocated stream channel east of Cocoa Avenue. A 112” (W) x 75” (H) access culvert for a possible future driveway to the south eastern property is proposed off Cocoa Avenue to convey the relocated stream. A 96” RCP culvert is proposed to convey the stream under Governor Road, east of Cocoa Avenue, and a 112” (W) x 75” (H) culvert is proposed to convey the stream from Governor Road under the driveway of the antique barn located in the northeastern quadrant of the intersection of Governor Road and Cocoa Avenue. The stream channel relocation through the proposed section will depart from the existing channel near the existing culvert stream crossing under Cocoa Avenue upstream of Governor Road. It will rejoin the existing channel near the culvert stream crossing under Cocoa Avenue downstream of Governor Road, adjacent to Valley Road. The downstream limits of work for Area 3 are located near the intersection of Cocoa Avenue and Valley Road.
The project will also include three (3) sanitary sewer stream crossings. The sanitary sewer stream crossings are associated with upgrades to the current sanitary sewer system within Area 3, Phase 1, due to periodic overloading during times of wet weather. These upgrades are necessary to maintain the integrity of the system.
There are 0.835 acres of emergent wetlands within Area 3, Phase 1 and the project will permanently disturb a total of 3,400 square feet of emergent wetland. A total of 7,000 square feet of emergent wetland will be constructed in order to mitigate the unavoidable wetland disturbance and to compensate for any potential indirect wetland impacts.
Area 3, Phase 2 (“Village Area”) of the Stormwater Improvement Project will include approximately 2,500 linear feet of storm sewer and associated inlets. The system will be located on Areba Avenue, Cedar Avenue, Sixth Street, I Street, W. Maple Avenue, Cocoa Avenue, Elm Avenue, and H Street. The storm sewer system will tie into the existing 3’ x 12’ box culvert near the athletic fields.
Project Cost and Funding:
The expected construction cost of storm sewer and sanitary sewer improvements in Area 3, Phase 1 and Phase 2 is $1.5 million that will be funded by a combination of a state H2O Grant and a Pennsylvania Infrastructure Bank Loan, secured by Derry Township and funds from the Derry Township Municipal Authority.
