Irrigation Subcommittee Meeting of July 21, 2009

 

Attendees:  Don Streseman, Ed Lauchner, Tom Watson, Shari Davis, Bob Pleski.  Ken Wolford did not attend due to illness.

 

Topic 1:  Ken has used the Dickson data pressure logger on the 5th green and the 14th tee.  The pressure on the 5th green is abnormally low and varies from 50-65 psi, significantly below the 82 psi that should be provided to the Rainbird heads.  It looks like our PRV 1 and 2 are out of adjustment and need to be rebuilt and readjusted as we previously discussed.  These apparently were last serviced by Mark Hadkin of Auburn Pump in 1997. 

 

Topic 2:  Pipe breaks.  Ed Lauchner brought four failed items, all of which were 2" threaded fittings.  In discussion, it was agreed that threaded fittings are weaker than glued fittings and that threaded fittings should be avoided if at all possible.  Further, in discussing this later by phone with Ed Norum, Senior Engineer at U.C. Fresno, CIT, he reiterated the weakness of (tapered) threaded fittings and they should be avoided wherever possible.  When threaded fittings are needed, the Acme non-tapered thread with O-ring seal, should be used.  

 

Topics 3 & 4:  The watering distribution uniformity, using the Toro heads on Fairway 15, on May 14, '09, showed a distribution uniformity of 70% and a graph from Chuck Murphy displayed similar results.  These tests showed significantly poorer uniformity than tests done last September using the Rainbird heads (88% uniformity).

 

Bob Pleski will contact Ken Wolford and discuss this with the Toro salesman.  One question to Kevin Eppich, will be:  What is the calculated distribution uniformity of the heads we tested with the spacing of 63 ft?

 

Topic 5:  Has the letter that Bob Pleski sent to Ken Wolford on 7/9/09 about Rainbird fast-closing valves and a suggested redesign by Rainbird to include a slow-closing valves been forwarded to Rainbird and have we received any reply? 

 

Topic 6:  Water hammer research project at UC Fresno.  The attached letter, dated 7/21/09, to Ed Norum, outlines what we are asking them to do and what the funding requirements would be.  Once this information is received, Bob Pleski will summarize it in a request to the LWW Board of Directors via the Golf Committee asking for funding that may be requested from LWW to UC Fresno.

 

Topic 7:  Watering of the greens in the summer afternoons - no information available. 

 

Topic 8:  Hydrophobic soil.  Bob Pleski should request of the Golf Committee that our present charter be expanded to include the study of hydrophobic soil.  Do we have it, to what degree, and how to correct. 

 

Other topics:  To be investigated: 

        1) Better air separation at the pump station. 

        2) Can we reduce the pressure out of the pump station?

        3) What pressure should pressure reducing valves, PRV 1 & 2, be set?

        4) Record the On and Off time of the pressure maintenance pump at the pump station.  If the On-time increases significantly, it indicates there is abnormal leakage somewhere on the course. When the pump station was installed, the On-time was about 30 sec. and the Off-time about 1 min.  It seems that this ratio of On vs. Off time would be a good management tool to monitor total leakage of all piping, including the heads.

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Attachment: E-mail note to Edward Norum

 

 

In follow-up of our conversation of 7/20/09, I am outlining the questions that we would like to have answered about pipe stresses in our underground piping. 

 

First of all, we pressurize our system around the clock 365 days a year from a variable frequency drive pumping system.  Therefore, there should be little pressure transients coming from our pumping system.     

 

We would like to know, based on actual test measurements, the following: 

       A.  The peak pressure caused by water hammer due to fast shutoff valves on the sprinkler heads:

                   

        B.  The pulling force on the pipes as a column of water is stopped:

                   

The tests A and B above, should be done using the following variables:

        - Valve shutoff time of 20 ms, 30 ms, 50 ms, 100 ms, 200 ms, 500 ms, 1 sec, 2 sec.

        - Velocity of water flow 3.5 ft/sec and 4 ft/sec.

        - Length of pipe before sprinkler head of 60 ft, 70 ft.

        - Pipe diameter of 1-1/2" and 2" nominal.

 

We would like to know what your estimated project funding would be to do the above study.  What portion, if any, would you expect to come from Lake Wildwood? What timeframe would you estimate to complete the above study?