Ask The Droughtbusters: June 1997, Irrigation Q&A

DROUGHTBUSTER: The promise of low-volume irrigation for turf has lingered for more than a decade. It sounds so sensible...no evaporation loss, no over-spray, lower liability and reduced water use. The challenge has been the life expectancy of anything buried in the soil. Roots find their way into emitters. Debris in the water plugs the tiny orifices of pipes. Polyethylene hose gets crushed or cut fairly easily.

The Center for Irrigation Technology at California State University in Fresno is the leader in research of buried low-volume irrigation. However, unless you can accept a four- or five-year lifespan for a buried drip system, the outlook has been bleak thus far.

This past year, research at CIT and the Landscape Irrigation Science Department at Cal Poly Pomona has restored hope. It’s called wick irrigation and is the brainchild of a Texas aeronautical engineer by the name of Joe Biles. Some people refer to it as micro-flood. Nibco Irrigation Systems of Fresno, Calif., is the manufacturer and calls the product the Turf Bubbler Wick system.

The term wick refers to the water-spreading ability of turf’s spongelike mat and thatch. Water applied to one location on turf can spread horizontally 8 feet or more through thatch.

Wick irrigation uses the same PVC pipe normally used underground. The difference is a riser extending upward from the pipe to the surface. It consists of a threaded male fitting that fits into a tee, a small flow/check valve the size of a walnut and ¼-inch polyethylene tubing that extends to the surface (just below the cutting height of the turf). The tubing deposits water on the turf and the thatch distributes it. There are no emitters to clog, no overspray to deal with and no moving parts to break. Seems almost too simple to work, but it does. The key is the spacing of the risers.

If you have dry spots with an overhead sprinkler system, install wick risers in the dry spots. In many cases, you can replace existing sprayheads with the wick risers and not even have to change the schedule on your controller.