Maine Medical Center R-Tank

Read about how a small-footprint subsurface stormwater storage system freed up space in a busy parking lot and saved the contractor precious time and money.

Maine Medical Center
Portland, Maine

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Provide a unique layout alternative for a subsurface stormwater storage system while also avoiding costly delays for construction vehicle traffic.

The original design of the stormwater system involved the use of a “pipe and stone” storage system which had a large footprint. There were concerns that during construction the pipe system could be damaged by the weight of the crane (for erecting the building) and heavy delivery vehicles.


Ferguson was engaged by the general contractor and the engineer of record to develop an efficient and customized R-Tank module layout design that reduced the footprint of the stormwater storage system while maintaining the equivalent amount of storage. The smaller footprint allowed for sufficient space for the crane to operate outside of the system footprint and allow for heavy construction vehicles to enter the site.

Product Advantages

  • 95% void space provided the most efficient storage and minimized the system’s footprint
  • Module Strength—easily supports traffic loads
  • Versatile system layout
  • Pre-assembled modules for fast installation
  • Inspection/maintenance row for system accessibility, inspection and maintenance


Maine Medical Center’s main campus, the largest medical facility in the state, is in the heart of Portland and serves Maine and northern New England. The main campus is located in Maine’s most densely populated neighborhood and provides medical resources to people from all walks of life. This multi-campus teaching hospital is considered one of the top hospitals in the U.S. and is home to the Barbara Bush Children’s Hospital (also considered one of the top children’s hospital in the country).

Project Scope

The hospital has seen significant growth over the years. Finding space in Portland’s urban environment and the fast-growing housing market has proven to be a challenge for the hospital’s expansion. Finding a large enough space for staff and visitor parking has been one of the hospital’s main challenges during this period of growth. The hospital acquired nearby property to redevelop and construct a large-scale parking lot for staff and visitors. The parking lot required a subsurface stormwater detention system to maximize on-site space and to efficiently use this highly-valuable property.


The design engineer utilized the R-TankHD Subsurface Detention System to create a subsurface layout designed to minimize the impact of construction activities. This layout provided enough space for construction vehicle traffic to continue without any slowdowns; other layouts would have forced construction vehicles to go around, slowing down the overall progress of the project. The R-TankHD Subsurface Detention System is a simple way to accommodate site-specific constraints and a viable solution for stormwater design challenges. Even in the field when unexpected conflicts arise, the R-tank system layout can be modified while still adhering to the required storage volume of the design. In some instances where conflicting utilities posed a challenge, the R-Tank modules were relocated (not removed) to provide the same storage volume for the entire system.


Ferguson’s engineering team quickly provided an R-Tank system design to keep the project on schedule. Ferguson gave support throughout the construction process, assisting the contractor with answers to installation questions. Ferguson’s detailed knowledge goes beyond materials and products. We understand the challenges and costs associated with projects that go over the scheduled time, and we were, therefore, able to help this project stay on schedule.

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