Sub-Surface Drainage Systems
Again, this is when your soil tests will come in handy. Two of the variables you may run into is coarse soil and/or fine soil. Coarse soils like sand tend to drain better than fine soils like clay. However, coarse soils could supply too much aeration and may not be able to be compacted to your standards. There are three popular types of drainage systems used today on sports fields; pipe drains, strip drains, and sand slit drainage.
Pipe drains have been used for years and, while aiding in overall drainage, are primarily used to lower the water table in an area, allowing the surface to dry, and to hold the water as it discharges to its final location. Originally these systems used clay tile and more recently, corrugated plastic pipe. They range from 18 inches to 3 feet deep. The trench is filled with gravel or coarse sand to the field subgrade.
Next are strip drains, which are becoming much more common as a means of draining athletic fields. Strip drains are narrow trenches 2 to 4 inches wide that are cut with specialized trenchers from 8 to 18 inches deep. They are much more effective in quickly removing surface water from sports fields than pipe drains. The strip drains are connected to a perimeter collector. The collector should be sized to manage the volume of water collected from the series of strip drains. The strip drains should be placed at a 45-degree angle to the direction of the slope. This will allow them to be installed at a consistent depth and keep a slope in the pipe.
The sand slit drainage system consists of a matrix of narrow 1.75-inch-wide sand slits on 12 to 20-inch centers. These are cut 8 inches deep and intersect at 90-degree angles to a series of sub-drains installed on 10 to 20-foot centers. This system promotes rapid surface drainage with sand trenches every 12 to 20 inches to allow water to enter the drainage system rapidly. These sand trenches will also improve the aeration of the field and hold moisture in the soil profile when excess is not present.
Whatever drainage system you and your team decide to go with will be a significant part of any field manager’s budget. However, it’s so important to have a field drainage system that fits your field’s specifications and variables because anything less than a professional drainage installation could cost you big time in the future. We’re here to help you do what’s best for your field and budget.