When the Clarington Tiger-Cats, a minor league professional football team in Ontario, Canada, began planning construction of a new athletic field, landscape architects needed to identify a drainage approach that would work for a space that was heavily and continuously used.
A tile drain would typically be specified for this type of project, but tile drains have an inherent challenge — to install this type of drain, gravel must be delivered, stockpiled, and moved around the construction site, which is not ideal for a playing surface because of extensive subgrade compaction. It also requires a high level of labor and heavy equipment costs.
Landscape architects also considered using a vertical strip drain system, but this method requires a significant amount of sand backfill, which has differential settlement issues. This would entail future maintenance costs, which were a key concern for project planners.
An NDS EZflow Drainage System was selected because it requires no gravel. It consists of three or four slotted corrugated pipes surrounded by NDS poly-rock, a lightweight gravel substitute, all wrapped in a geotextile fabric. By eliminating the need to transport, shovel, and move heavy gravel, it cuts installation time in half, and is durable, crush-proof, and has a lifespan of 100 years. The EZflow system is designed to take water out of the soil and pipe it to a safe discharge point.
EZFflow can be covered with native soil instead of sand. Native soil will recuperate faster than sand, and it can take more of a beating from heavy use. Also, EZflow allows the reduction of slope around the field, making it easier for people to view the action on the field.
For the Tiger-Cats’ project, landscape architects leveled the subgrade 1 degree, then excavated 12-inch-deep, 16-inch-wide trenches in a herringbone pattern. The EZflow pipe was then placed in the trench, covered with geotextile paper, and then topped with screened native topsoil.
Approximately 5,200 linear feet of EZflow was installed, and project planners estimated an overall cost savings of 25 percent compared with traditional gravel and pipe. One measure of the project’s success is how well it handles the freeze/thaw cycle in Canada – the product has performed well and there have been no settlement issues.