Location: Old Westbury, N.Y.
Application: Detention & Infiltration
Product Used: 11′-4” DoubleTrap
Total Water Stored: 251,173 cf
Number of Basins: 1
Number of Pieces: 388
Consulting Engineer: VHB
General Contractor: Posillico Civil
Installing Contractor: Darr Construction Equipment Corp.
A large stormwater management system was installed under the main campus parking lot of New York Institute of Technology (New York Tech) in Old Westbury, N.Y. The system was needed to provide adequate stormwater management with the increased rainfall in the region over the past seven years. During moderate to heavy rain events, a pond adjacent to multiple campus buildings would flood, causing significant problems to the campus.
“Our existing system consisted of a drainage pond with a piped outlet to a floodplain; when the collection of water in the pond exceeded the output, the pond would spill over towards an entryway of the building. If left unchecked, water would flood the first floor and basement of that building, causing several thousands of dollars in damage an occurrence,” explained Greg Loeven, Project Manager for New York Institute of Technology’s Facilities Operations Department.
As an immediate solution to minimize the risk of flooding, the school would use sandbags at the entrance of the building and pump the pond water before and during the storm. However, pumping the pond was causing the floodplain to become overwhelmed, and stormwater would spill over onto a roadway and into the neighboring village.
In order to provide a more effective solution for the campus, New York Tech worked with VHB engineering and StormTrap to design a system that would meet local stormwater storage requirements for water quality and quantity. An 11’-4’’ tall, DoubleTrap, with 194 modular precast units, was selected to manage the runoff. The system is capable of storing 251,173 cf and has openings in the bottom of some of the internal pieces to allow water to infiltrate into the soil.
The StormTrap units were placed on a 6’’ stone base foundation, and an excavator was used to easily set the pieces in place. After the units were installed, ¾’’ aggregate stone was used to backfill around the perimeter of the basin.
The project team faced some challenges regarding project timing, scheduling, and meeting stormwater storage requirements. The first project challenge, according to Loeven, was that the construction window for this project was very short, a total of 64 working days. Construction had to be completed by September 1st, for the beginning of the fall semester. Logistics was another concern for the university as its medical clinic is located in front of the work zone; therefore, patient and staff parking and pedestrian traffic had to be well coordinated. Another significant challenge, according to the project engineer, was that the system had to provide adequate stormwater storage capacity per local requirements while also reducing the footprint.
The StormTrap design allowed the system to fit within a limited area and maximize the stormwater volume of the system. Minimizing the system’s footprint helped to reduce disturbance to existing parking facilities and save costs in pavement restoration after the installation, affirmed Angelo Laino, PE, Project Manager at VHB.
Project coordination was also essential to deliver the project on time and without disrupting the school and medical clinic operations. StormTrap worked with the New York Tech project management team to ensure the installation of the system was aligned with their logistics plan by coordinating the delivery of the StormTrap units within the daily scheduling constraints.
The project manager affirmed that working with StormTrap was an excellent experience, “StormTrap met with us during the concept phase and understood our goals and timelines. They exceeded their own production schedule to ensure our project had all the materials necessary to complete on time.” Laino, the engineer of record, also stated, “excellent service, I strongly appreciate the involvement of staff from design through installation.”