The pumpstation pumps from the main irrigation pond that is fed by runoff from the upper half of the golf course in addition to a high capacity well. The pumpstation maintain a pressure of 90 pounds per square inch in the system. Green heads are spaced in a square pattern and put out 30 to 40 gallons per minute 55' to 85' feet. The big heads in the fairway throw 60 gallons per minute up to 98'.
This week we had a faulty sensor four feet under the water in the pumphouse that would tell the pumpstation it was out of water so the pumps would stop running. In the morning we would see the error and assume we ran out of water and the 2 foot inlet filter was clogged. However we could not recreate this problem during the day no matter how much water we pumped. After three nights of a total system failure and watering 10-15% of the course we figured out we did not have a water flow problem but a faulty sensor. It was a quick fix but something you do not expect.
Because of that you may of noticed the challenge we have greening the turf areas back up after they brown due to our heavy soils. They hold moisture well but when they get dry and turn brown or dormant they stay that way for days no matter how much water we apply. Although we have caught up on our application rates the areas still look off color and will for the next few days until they slowly come back. This is different than the courses I have worked at previously with normal or rocky soils. At those facilities areas would be wilted grey and brown in the afternoon and a little water would turn them emerald green the following morning.
With over 500 irrigation heads one or two of them break every time we water either through wear and age along with partially clogged nozzles that change distribution. We spend the first few hours each morning trying to find those broken heads and improving coverage.
Often golfers ask why if we have a automatic system we still have sprinklers on at 7 AM. Early morning is the best time to water for plant health and to reduce fungus and disease problems so we start the system as late as we can but we can only water so many heads at a time without pressure and performance loss. So we water the early holes (1-5, 10-14 and 19-22) early in the morning and the later or finishing holes around dawn.
The worst time for us or you to water is in the mid to late afternoon. The grass does not like to be wet during the heat of the day and a lot of the water evaporates before it hits the ground.
How do we decide when and how much to water? We use information from our weather station and a e-mail service from UW-Madison to determine our Evapotranspiration Rate (ET Rate). The ET is a combination of how much water a the grass plants would use in a day plus the amount of water evaporated into the atmosphere. The ET rate is calculated by temperature, sunshine, wind, humidity and dew point. Believe it or not the rate is usually higher in June than it is the hot dog days of August because the humidity is lower in June.
So far in the month of June our ET has averaged an amazing .23" or almost a quarter inch a day of water use or evaporation with peak days of .34". University research has shown that plants are healthiest if we replace 80% of the ET. .23' x 80% equals .18" of water a day we need to apply for healthy turf. Under normal circumstances we try to water ever second or third day so we try to apply .36" or .54' of water per application.
No matter how new or technologically advanced a irrigation system is they do not replace rain and in Wisconsin they are designed only to supplement rain. Long term dry periods lead to wet spots from too much water and dry spots from too little water. We do our best to find these areas and increase or decrease coverage but our biggest problem is right around the heads or right in the center of the fairway where extra water is spilt when the heads turn on and off and with the single row spacing the area is hit by three heads.
Perfect green is not our goal with irrigation. Our goal is healthy but playable turf and dry and a little brown is better than wet and bright green.
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