Our Irrigation System
Around the middle of April each year our irrigation system is turned on and water flows to your sprinkler heads at 40 pounds per square inch (psi) to deliver exactly what your water allocation allows: 8.47 gallons per minute (gpm) for each acre you own. Getting that water from the Okanogan River to irrigate your fields or lawns involves some large and expensive electrical and hydraulic equipment, and an extensive system of pipes, valves and flow control devices.
We operate a two-stage pumping system: The first moves water from the river to a sump at the base of the hill-slope. The second stage moves it up the hill and into our distribution system.
At the river we have two centrifugal pumps mounted on a heavy-duty plastic raft that draw water through a pair of rotating fish screens. These were installed to prevent threatened and endangered salmon native to the Okanogan watershed being drawn into the pumps and killed. The pumps are driven by a pair of 15 HP and 20 HP electric motors.
Flexible hoses connect the pumps to a 10" steel pipe which carries water up the river bank and through a culvert under Omak River Road to discharge into a concrete tank on land we own west of the road. Here the river sediment settles out before the water flows over a small weir into another chamber where our main pump lifts water about 200' up the hill to the flat where our subdivision sits.
The river pumps run continuously during each 48-hour irrigation "set" delivering around 2200 gpm to the sump. Excess water is returned to the river through two large diameter pipes. The main pump is a four-stage turbine driven by a 250 HP electric motor controlled by a Variable Frequency Drive (VFD). Installed in the Spring of 2011, the VFD maintains a steady pressure in the 12" mainline by speeding up or slowing down the motor as demand for water increases or decreases during the irrigation set.
Each land parcel in Vista Vue is connected to the main distribution system through an orifice plate calibrated to each owner's allocation of water and, usually, a shut-off valve, a control valve and a Sonntag filter, all located above-ground. Vista Vu Water Users' Association owns and maintains everything up to, and including the shut-off valve. After that, the filter, piping and sprinkler system are the land-owners' responsibility.
During the winter of 2018-19 the system was extensively overhauled. New centrifugal pumps and steel piping were installed on the raft and the main pump motor was rebuilt. Stu Skidmore fabricated a metal extension installed at the bow of the raft to protect the plastic buoyancy chambers from beaver damage.
Operating the System
Our surface water diversion certificate allows us to pump water from the Okanogan River between Apr 1st and Nov 1st. Usually we run from mid-Apr to mid-Oct to avoid frosts. At the end of each irrigation season we remove the raft from the river, and drain the entire system. Critical parts of the system are winterized. During the Winter months the fish screens are dismantled; pumps and motors are inspected for wear or damage and, when necessary, repaired. (After shut down, for a $35 fee, Stu Skidmore will blow out members' irrigation lines.)
Removing and installing the raft is accomplished using work parties - VVWUA members who volunteer their skills and time - and takes most of a morning. A boom truck removes the disassembled pumps, motors and hoses from the raft before lifting the unweighted raft on to Omak River Road and, in a second lift, into the pump-house compound for Winter storage. In Spring the process is reversed; the system is tested for leaks, broken risers or other issues before the first set is run.
Starting Up and Shutting Down the Pumps
We run a 48-hour on, 36-hour off schedule during the irrigation season except when weather conditions reach certain thresholds: If there has been 2/10ths inches or more rain recorded on an on-site rain gage in the preceding 12 hours, the pumps will be shut off, or not started. If the temperature is forecast to exceed 95 deg. or 90 deg. with 10 mph or greater winds, the pumps will be run continuously until those conditions end.
The pumps must be started on Sunday morning and Wednesday evening, and shut down Tuesday morning and Friday evening every week of the season. Some basic knowledge about the way the system functions is necessary to safely carry out the start-up and shut-down procedures. For that reason your Board of Trustees has decided to limit the number of operators to six, all of whom have a good working knowledge of the electrical and mechanical aspects of the system.
2020 Irrigation Start-Up Roster
| 5/6/20 || Stu Skidmore
|5/20/20 ||Tracy Oestreich
|6/3/20 ||Dean Harrison
|6/17/20 ||Dean Harrison
|7/1/20 ||Roscoe Howard
|7/15/20 ||Dean Harrison
|7/29/20 ||Roscoe Howard
||Udi Medrano |
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further information contact: Stu Skidmore, President; Mike Stenberg, Vice President;
Gary Carlton, Secretary; or, Tracy Oestreich, Trustee;
We welcome your comments on the website.