Bi-County Supply Main

Alignment Study & Design, Montgomery & Prince George's County, MD

WSSC Bi-County Supply Main Alignment Study investigated alternative alignments and associated impacts of constructing a 30,000 linear foot, 84-inch water transmission main in Montgomery County, Maryland.  The project scope was divided into two phases - alignment study and design. 

In the Alignment Study Phase, PEER was responsible for:

  • Conducting detailed environmental and community impact studies for nine potential alignments.
  • Developing evaluation criteria and rating the impacts of each potential alignment across multiple environmental and community resources such as vegetation, wildlife habitats, traffic, archaeological and residential ambience (e.g. noise, dust and exhaust).
  • Conducting site visits and walk-throughs, researching documents and obtaining information from agencies such as Maryland Historical Trust to assess the impacts of the proposed alignments on the community and environment.
  • Designing and developing a comprehensive community outreach program and preparing brochures, pamphlets and other materials for community outreach meetings.

 In the Design Phase PEER:  

  • Performed environmental and community assessments to determine the optimal alignment and construction methodology (open cut vs. tunnel) for the pipeline in conjunction with technical, cost, permitting requirements and other factors.
  • Prepared design plans and specifications for civil/site construction, sediment and erosion control plans.
  • Assisted with preparation of structural (vaults) and mechanical (shafts and connections) drawings.
  • Prepared stormwater management and sediment and erosion control plans for approval by the Maryland Department of the Environment.

Currently, in the Construction Phase, PEER is:

  • Reviewing construction contractor submittals, including change orders, Requests for Information (RFIs) and invoices.
  • Preparing a fluvial geomorphic study, concept plan and report.
  • Surveying and preparing geological maps and logs of the tunnel side walls and crown.
  • Examining the rock bolts and wire mesh of the tunnel support structure.
  • Preparing concept plan and report for the design and implementation of a stream restoration/stabilization project for Old Farm Creek, a tributary of Cabin John Creek.