NBC Phase III CSO Program Management

Providence, RI

NBC Phase III CSO Program Management

Providence, RI
A Cleaner Bay
  • Design of green stormwater infrastructure (GSI)
  • Geotechnical/geological exploration program
  • Environmental site assessments
  • Structural design of tunnel dewatering pump station
  • Environmental permitting

Pare Corporation has teamed with Stantec to assist the Narragansett Bay Commission (NBC) with implementing its Phase III Combined Sewer Overflow (CSO) abatement program. The overall objective of Phase III is to improve water quality in Narragansett Bay by reducing the frequency and volume of combined sewer overflows into the Blackstone River and other tributaries during wet weather events. The Stantec/Pare team is serving as Program Manager and Construction Manager for the NBC, which includes program implementation and oversight, planning, conceptual design, and construction administration.

Pare led the geotechnical/geological investigation program for Phase III. An extensive program of subsurface investigations was done over two years to support the design. Pare directed over 50 deep borings cored through bedrock to the approximate depth of the tunnel (200-250 feet below ground surface). Soil and groundwater sampling was performed at many of these borings. The results of the geotechnical and environmental testing programs were reported in a Geotechnical Data Report (GDR) and Environmental Data Report (EDR), both prepared by Pare.

Pare served as lead designer on two green stormwater infrastructure projects and is managing the design of many other GSI projects. GSI was added to the Phase III CSO Program to supplement the more traditional, large “grey” projects based on input from regulators and stakeholders. The objective of the GSI program is to intercept and filter stormwater prior to it entering the combined sewer system.

Pare is the structural design lead for the tunnel dewatering pump station. The pump station will be a 90-foot diameter shaft approximately 250 feet deep with an at-grade controls building. Pare also helped evaluate options for the handling and disposal of muck generated from tunnel construction.