Winterizing the Irrigation System

One of the most important activities we do every fall is winterizing the irrigation system. Under your feet is almost 8 miles of plastic pipe that, on average, is only 24 inches deep. The shallow depth means the water inside the pipe will freeze and shatter the pipe if it is not expelled before winter. Draining the system through low points eliminates some of the water but not all of it. To understand why gravity draining is only of a partial help an explanation of how the irrigation system works might help.

Without going into too much detail, the irrigation system at KGC is a hodge-podge of control methods and piping schemes. The front nine is a "block system" which is best described as a constantly pressurized mainline that supplies a number of laterals irrigation lines in which a single valve controls multiple sprinklers. The laterals are only pressurized when the valve opens and the sprinkler heads are running. The back nine is a "looped system". In this type of system smaller pipe feeds off of a larger mainline at two points (usually at the start and end of a fairway). Each sprinkler heads has a valve and can operate on its own. Water is supplied to each head by the smaller looped line which is constantly pressurized.

The valves in both the front and back hold water and are not drained by gravity alone. Even a little water left at the base of a sprinkler valve can destroy a head. The following picture shows an irrigation head where the ice that formed within the valve at the base of the sprinkler split the casing top from bottom. The interesting part of the picture is how little ice was needed to damage the sprinkler pot.

Damaged Pot

The only way we have to remove unwanted water from the irrigation system is to use compressed air. We use a compressor that able to generate 750 cubic feet/minute (cfm) of air. As a point of reference, a small portable compressor used for air nailers can run up to 2.5 - 5 cfm. We rent a compressor locally and use it for 2 days. We close nine holes at a time for convenience and safety. It takes a full 8 to 10 hour day to completely blow the back nine and only a 6 hour day for the front. This relates mostly to the different control systems we have on each nine ( see April 15th posting for brief explanation of control systems at KGC).

Mixture of Air and Water Being
Forced out Sprinklers

Generally, we have pretty good success with little or no damage the following spring.

The clubhouse, on course bathrooms, snack shack, river pumphouse, and reservoir pumphouse all have to be winterized as well but for those we use a smaller compressor and R.V. anti-freeze to keep the fixtures from freezing. There have been years, like last year for example, where the cold came early and hard. I seemed to have misplaced the pictures I took but the damage last year included frozen control satellites, burst irrigation pipes, frozen valves, and split plumbing fixtures. At this point in time we seem to be ahead of last year with respect to "irrigation winterizing", that is. Hopefully, that hold true for all other processes we have yet to complete!