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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. Flexible hoses connect the pumps to a Operating the SystemOur 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.) Starting Up and Shutting Down the PumpsWe run a 48-hour on, 36-hour off schedule during the irrigation season except when weather conditions reach certain thresholds: 2020 Irrigation Start-Up Roster
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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.
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.
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.