When the design plan of the Williamson County Medical Center, in Nashville, TN came face to face with several unique challenges posed by regulatory and site constraints, they turned to CRH for a smart solution.
In particular, Nashville’s stormwater regulations require the use of Low Impact Development (LID) - strategies that use more natural means to manage rainwater where it falls. However, in many parts of Nashville, bedrock is typically very shallow, which requires expensive rock excavation, to allow for some of these LID features. Often, it requires the use of modified designs that work well with the rocky ground.
Fully integrated stormwater management solution, aligned with new regulations
After conducting a comprehensive analysis, CRH proposed the use of the PermeCapture® integrated stormwater management system from CRH Company Oldcastle Infrastructure, which combines permeable pavers, filtration media, and StormCapture® detention and retention vaults.
The PermeCapture system designed for the Williamson County Medical Center utilized 100,000 square feet of Belgard’s permeable interlocking concrete pavers to capture, convey, and filter stormwater before entering the underground storage system which occupies only 2,500 cubic meters of excavated space.
The StormCapture system provided storage volume equal to an Olympic-sized swimming pool or over 660,000 US gallons of stormwater during a single rain event. By comparison, traditional stormwater systems might require two or even three times more space, to accommodate a similar capacity.
Lower costs and quicker to complete
What’s more, by using PermeCapture, rock excavation costs were lowered by over 25% compared to conventional stormwater infrastructure, while the reduction in rock excavation also enabled the project to complete three weeks ahead of schedule.
The permeable paver system further reduced the stormwater management costs by replacing most of the stormwater inlets and piping throughout the site and eliminating the need for a separate water quality device because, according to Nashville’s regulations, the permeable paver system can be used for capture, conveyance, and to meet the water quality requirements for the site.
PermeCapture provided the most cost-effective stormwater solution for this project, by reducing rock excavation, stormwater inlets and piping, maximizing usable land and eliminating the need for separate water quality devices.
