The City of Raleigh Public Utilities Department (CORPUD) constructed a parallel sewer line at the Crabtree Basin to significantly reduce the risk of sanitary sewer overflows, provide for future infrastructure needs through 2030, and improve the existing Crabtree Creek Lift Station.
The sanitary sewer gravity starts near Mine Creek located east of US 70 (Glenwood Avenue) near Crabtree Valley Mall and goes to an existing pump station at the I-440/US 64 Bypass.
SEPI completed an environmental liability valuation/records review to assist the design engineers early in the planning process to identify environmental contamination ‘hotspots’ that may affect the proposed alignment. SEPI compiled the study results into a report and GIS maps to show the relative position of the historic contamination and the proposed sewer line. Once the final corridor was selected, the Phase I Environmental Site Assessment (ESA) was completed by SEPI.
To provide the City with additional cost savings, the field review required for this task was completed at the same time as the fieldwork. SEPI completed a wetland, stream, and riparian buffer determination review within the proposed study area.
Approximately 0.5-acres of emergent wetlands, 1.5-acres of emergent/forested wetlands, and 1.6-acres of forested wetlands were identified within the proposed project corridor during the wetland determination for a total of approximately 3.6-acres of jurisdictional wetlands.
After the field review, SEPI digitized the location of wetlands, streams, and buffers in GIS. The design engineer utilized the information to avoid and minimize impacts to wetlands, streams, and buffers to the maximum extent practical.
In addition, SEPI completed project permitting including a Section 404/401 and Neuse buffer authorization request after the design of the sewer line had been finalized and subsequently negotiated and identified needed compensatory mitigation for the wetland, stream, and buffer impacts.