This is a wonky post about how the Bureau of Reclamation determines water releases out of Prineville Reservoir into the Crooked River below Bowman Dam. The summary is that this water year, “contracted storage” (irrigators and the City of Prineville) will be allocated 81,547 acre feet of water and “uncontracted storage” will be only 19,331 AF. This is the water that will stay in the river all the way to Lake Billy Chinook and will determine the health of the aquatic ecosystem below the City of Prineville. Keep reading if you want the gory details.

The document below, “Final Storage Allocations for 2026, Prineville Reservoir, Crooked River Federal Reclamation Project, Oregon”, was emailed yesterday. Let me try to explain it. As you can see there are 21 entities listed as “contractors”, or those holding rights to a portion of the water stored in the reservoir. Ochoco Irrigation District holds the most rights. When the reservoir is full the total contracted storage is 86,113 AF. There is an additional 62,520 AF of uncontracted storage that is commonly called fish water, which by law is to be release for the maximum benefit of fish and wildlife. In a good water year this ratio of 58% to irrigators and 42% to fish provides reasonable habitat for the aquatic ecosystem.

The problem is that in bad water years this ratio is not maintained. Contractors get all of their water before fish. This water year irrigators will get 100% of their contracts (94.70% after accounting for evaporation and sedimentation) even though the reservoir did not fill. The remaining water, the fish water, is only 31% of the uncontracted storage at full fill or 24% of what the irrigators will receive this year.

Side note: Central Oregon Irrigation District and North Unit Irrigation District patrons, and I believe other local irrigators, are all receiving reduced water deliveries this year. This is not the case for irrigators getting water from Prineville Reservoir.