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Northwood School Expansion

Northwood, Ohio


Northwood Schools


ESA Engineers, Surveyors, & Associates


Rudolph Libbe


May 2017

Technical Description:

  • (24) Terre Arch™ 26 Chambers
  • CDS® Hydrodynamic Separator

The Northwood City School district constructed a new pre-k through 12 school as part of a modernization and consolidation effort.

The school was located on a very shallow site with limited space. After reviewing the site and the proposed layout, it was determined that above ground storage of stormwater runoff would not be possible so the engineer began to look at underground storage and treatment options.

After reviewing the many options offered by Contech, the engineer selected the Terre Arch concrete detention system. Terre Arch is a modular, multi-chambered, precast concrete stormwater storage system engineered for underground installation.

The system was placed under the bus lanes and main drive in front of the schoolTerre Arch was selected because of the shallow cover and the ability to withstand the heavy loading of the buses.  In addition, the installed cost comparison provided by Contech alleviated any concerns that a concrete solution would be too expensive for the site. CDS hydrodynamic separator was selected to meet local pretreatment requirements and to extend the lifespan of the system.

Contech provided the engineer preliminary sizing and cost estimates for multiple systems and on-site installation assistance from a Contech Field Specialist. The Field Specialist performed a pre-construction meeting by phone before meeting the contractor on-site the day of the installation. The Field Specialist coordinated delivery from the precaster for just in time delivery and provided the contractor guidance on installation.

The site was excavated and prepared the day before the installation took place. The Terre Arch units were picked up with swift lifts and set in place using an excavator. The entire installation was completed in less than one day. The installation crew commented on the speed and ease of installation. They had not installed a Terre Arch system before, but were comfortable with it in no time.

Shortly after the installation, an engineer in another part of the state was interested in using Terre Arch on one of their projects. However, they had never used one and wanted to speak to a contractor who had experience installing one. The contractor’s superintendent gave the engineer a positive review of Terre Arch along with a breakdown of the system estimates for labor and backfill. After the phone conversation, the engineer felt reassured and confident in the Terre Arch system.

Technical Description:

  • (24) Terre Arch™ 26 Chambers
  • CDS® Hydrodynamic Separator

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