Drainage is a critical part of promoting turf health throughout the season, especially in low-lying areas and poorly drained soils. That said, not all drainage is the same and it is important that the right materials and methods are used when installing drainage. For example, installing perforated pipe in a trench but then backfilling with a heavy-clay native soil will not improve conditions. There have been several extensive articles on drainage and I’ve included a link to those at the end. The following are just a few of the most important things to keep in mind when installing drainage.

When perforated pipe is installed, oftentimes the recommendation is to backfill the trenches with a sand or “dirty sand”. Sometimes the recommendation is even more specific, such as a backfill material consisting of 80% sand and 20% soil. However, even these recommendations may not be specific enough, and performance characteristics of the material could still vary widely.

Two key requirements for backfill material are infiltration rate and the balance between aeration and capillary porosity. That is, the mix must allow water to move down to the drainage pipe rapidly from the surface, but it should also retain adequate moisture once drainage is complete. The article “Understanding Water Relations in Mixes for Sand-Channel Drains” explains this topic in further detail. It is always a good idea to have an accredited soil testing laboratory test the mix that is going to be used to confirm performance characteristics.

The depth and slope at which pipe is installed is also important, for obvious reasons. The ideal depth can vary and is dictated by topography, but a good rule of thumb is the top of the pipe should not be less than a foot below the surface. In some cases, such as sand channel drainage in putting greens, the pipe can be 20 inches or more below the surface. The pipe should also maintain a minimum of 1% slope to the outlet.

Some of this information may seem obvious to those that have installed drainage extensively, but it is worth reiterating to those with less experience. The importance of proper materials and methods cannot be overstated when it comes to drainage.

The USGA digital collection Drainage on Golf Courses contains several articles that provide great insight on several aspects of this important topic. If you would like more information or wish to discuss drainage issues at your course, contact your regional USGA agronomist.

Central Region Agronomists:

Paul Jacobs, agronomist – pjacobs@usga.org

Zach Nicoludis, agronomist – znicoludis@usga.org

Information on the USGA’s Course Consulting Service

Contact the Green Section Staff