Taming the Multi-Stakeholder Hydra: A case study in planning, permitting, design and construction of a gravity sewer meeting Federal, State, and Private Stakeholder constraints.

摘要

This case study will discuss the intricacies in planning, designing, permitting and constructing a large-scale gravity sewer project for Loudoun Water in Loudoun County, VA. Located just west of Washington DC and currently one of the fastest growing areas in the country, Loudoun Water requires this new sewer to meet projected wastewater demands in their Horsepen Run sewershed. The 20,000 linear-foot pipeline of large diameter sewer (72/48/42 inch) crossed only four properties, but affected numerous stakeholders. A large portion of the project crossed the Washington Dulles International Airport, and also required extensive work under and around the new Metro Rail Silver Line. Stakeholders - each with unique and challenging requirements - included the following: 1. Metropolitan Washington Airports Authority (MWAA) 1.1 Federal NEPA applicability/constraints 1.2 Phase I Archaeological Survey 1.3 Specific Federal Aviation Administration blasting requirements 2. Capital Rail Constructors (CRC) (Metrorail Silver Line Phase 2 Design-Build Team) 2.1 Construction work area access 2.2 Coordination of design 2.3 Coordination of schedules 3. Washington Metropolitan Area Transit Authority (WMATA) 3.1 Coordination with ongoing construction project including buried infrastructure 4. Toll Road Investors Partnership Ⅱ (TRIP Ⅱ) - owner of the Dulles Greenway 4.1 Limited Access Highway Break to facilitate maintenance and construction 4.2 Multiple tunnel crossings under roadway and ramps 4.3 Required road closures as a result of blasting operations 5. Virginia Department of Transportation (VDOT) 5.1 Coordination of Horsepen Pond Emergency Spillway and Old Ox Road Widening Project 5.2 Multiple tunnel crossings under roadway and ramps 6. Dulles World Center (DWC a large private development) 6.1 Coordinate future sewer connections and avoidance of tree conservation areas 6.2 Coordination with ongoing construction activities 7. DC Water and Sewer Authority (DC WAS A) 7.1 Coordination for crossings of the Potomac Interceptor (PI), Indian Creek Sewer, and adjacent construction 7.2 Blasting and construction traffic concerns around existing Potomac Interceptor 8. Fairfax County 8.1 Provide capacity for future Fairfax wastewater flows 8.2 Facilitate division of Loudoun Water and Fairfax flow from an existing shared sewer via a flow splitter box and meter vault Timing for the project was driven by anticipated increased demands as well as a desire to design and construct the new sewer prior to construction of WMATA's new Metrorail Silver Line Phase 2, which had to be crossed in four locations. The Owner wanted to avoid conflicts during construction, reduce installation risks in the vicinity of an active light rail line, and avoid having to obtain approval from two federal authorities - MWAA and WMATA. An important nuance of the project is that MWAA is the Owner of the Metrorail Silver Line Project until its construction is complete. The initial concept was to design the project to approximately the 60% design level and install casing pipes to facilitate future installation of the sewer without encroaching into WMATA's easement. Through stakeholder meetings with MWAA it was learned installation of the casing pipes would 1) not preclude the need for future approvals from WMATA, and 2) the necessary easement could not be obtained without a full Phase 1 archaeological survey, 401/404 permit, and encroachment agreements from VDOT, and the Dulles Greenway (TRIP Ⅱ) for the entire pipeline length. Consequently, the design was modified to a 100% design in time to still meet the Owner's initial goal of installing its sewer project before the construction of the Silver Line. The presentation will outline the strategies implemented by the Project team to engage stakeholders and facilitate and expedite their review and approval. In addition to the early coordination with MWAA, there were varying levels of coordination required with each of the major stakeholders for various phases of the project, as summarized above.