Irrigation Woes

This beautiful water feature is not what we want to see. The irrigation blow-out pictured is on #15 red tee. It was caused from a valve on an inch and a half pipe attached to a three inch main line that broke off due to intense water hammer created when the pump turned on to water the night before.

 One of the first things GMS did when we came to Capital City CC was to asses the irrigation pump system. We found that the computer system that controls the pumps needed to be tweaked to help eliminate water hammer but we found that because of the design of the system we could only reduce in marginally. Water moving through pipes is a very powerful force when the volumes are as high as 1250 to 1350 gallons per minute.

Our irrigation system is continuously under a pressure of 85 psi.. When the sprinkler control system turns on a station, usually 3 to 16 sprinklers, the pressure is reduced in the pipes. There is a lot of pipes under the ground so it takes a while for the pump station located behind the swimming pool to sense this pressure loss and when it does the pump turns on. The source of our water is a very deep well. When the pump turns on the time it takes for the pump to bring the water up through the well and into the pipes is less then a minute but the pressure in the pipes is reduced down to, in most cases around 20 to 30 psi. The computer that controls the speed of the pump knows this and is working hard to catch up the loss of psi back to 85. Once the water reaches the pipes the gallons per minute is near 1100.

Water hammer is essentially a recoil of the energy water moving through the pipes creates and eventually hitting the end of the line. That energy has to go somewhere and what you see in the photo is where it went Wednesday night. The valve at 15 tee was the weak point this time. Unfortunately every time the pump turns on the same water hammer situation occurs. Most nights there is no blow-out, the energy is absorbed by the pipes but every water hammer event weakens the pipes. This has been going on for many, many years and the pipes are fatigued. This is a situation that puts the golf course at risk for major damage not only from damage that the blow-out could cause, but also the loss of grass because the entire system has to be shut down for repair. In the heat of the summer the greens are in big trouble if the system is shut down for four days or more.