The SPPC will pipe 3,000 linear feet of open canal. The complete SPPC will reduce seepage losses in the Central Oregon Canal by an estimated 5 cfs year-round (1,500 acre-feet per year). When complete, COID will temporarily lease the entire 5 cfs instream in the Deschutes River, pending release of the 2019 update of the Deschutes Basin Habitat Conservation Plan(DBHCP). The 5 cfs will be used to reduce the need for storage at Crane Prairie and/or Wickiup Reservoir to facilitate a permanent increase in minimum instream flow in the Upper Deschutes River during the winter.
In addition to piping the open canal, the SPPC will replace and improve the fish screen. The project will increase the area on the fish screen which will reduce the approach velocity by 45 percent and decrease descaling and impacts to fish. In addition to the fish screen approach velocity improvement, there will also be an improvement to head loss with the increased screen area. This head loss can increase efficiency for power production to the existing Siphon Power Plant by 2-5%.
The instream flow improvements are expected to provide benefit for the Oregon spotted frog which are present in the Upper Deschutes River upstream of Bend, Oregon. Instream flows in this reach are currently low in the winter due to irrigation storage, and a key element of the DBHCP for the Oregon spotted frog will be permanent increases in the winter minimum instream flow. Improvements to the fish screen are expected to provide.