Colfax Street Water Detention - GreenBlue Urban
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Colfax Street Water Detention


The water detention project on Colfax Street in Evanston, Illinois saw GreenBlue Urban's Pavement Support System installed as a more cost-effective alternate to a dry-well in a Chicago suburb. The property owner was building a new house in a neighborhood prone to flooding and wanted to ensure that the drainage plan was as aggressive as possible. The owner turned to Kettelkamp & Kettelkamp Landscape Architecture for recommendations on a more robust solution, who in turn suggested the use of GreenBlue Urban's Pavement Support System.

“The client wanted to ensure that the proposed civil engineering solution was aggressive enough for the amount of rainwater in his neighborhood,” explained Claire Kettelkamp, the project designer. “The 97% storage volume of GreenBlue Urban's Pavement Support System provided an excellent solution for this residence.”

stormwater rootspace storage

A zone under the front lawn of the property was selected for the storage area. The pavement support system was installed here to create a reservoir that would store excess stormwater and allow it to transport at a controlled rate. This provided the intended flood protection during the event of prolonged rainfall.

The pit location was 713 cubic feet, which provided ample space for the reservoir to ensure the drainage requirements. To accomplish the same storage volume with a stone mixture, it would have taken a pit approximately 2,250 cubic feet.

Due to the fact that a pavement support system holds approximately three times more volume than the stone mixture that was initially intended for the project, the excavation zone was significantly condensed, which equated to notable cost savings.

This saving in excavation costs, in addition to the superior robustness of the method, is what persuaded the civil engineer to change his specification from a stone mixture.

When installing stormwater storage solutions in urban areas, engineers are often faced with a multitude of underground utilities and built infrastructure that can significantly complicate an otherwise straightforward installation. Due to the modularity and versatility of GreenBlue Urban's Pavement Support System, services can be easily accommodated through customized configurations. The skeletal matrix even allows for utilities to be integrated through the completed assembly.

Rated for maximum vehicular traffic with minimal surface, this system is used under fire lanes and roadways - not just pedestrian areas. And with over 97% void space stormwater storage, they beat any other system in storage capacity and cost-effectiveness.