Here is a recent report from the Bureau of Reclamation on the water outlook for Prineville Reservoir. As you can see on page 3, a few days ago the reservoir was 35% full and flows into the Crooked River were only 49 cfs (47 cfs today), which is below the target set by ODFW for fish needs and the 80 cfs target in the Crooked River legislation. In summary, the BOR presentation implies that the outlook is not promising for the reservoir to fill which means flows into the Crooked River next winter after irrigation season ends will also likely be low. Keep reading for some commentary on the presentation prepared by BOR.
Slides 4 & 5: The gray bands show where the reservoir was 50% and 95% of the time for the last 30 years. These slides also show where it was for the last 2 water years for reference. These show that Prineville and Ochoco started the water year with well below average carry-over and has stayed at below average storage ever since. We are currently having equipment problems with Ochoco Dam so the decreasing storage shown on Slide 5 starting mid-December is likely incorrect.
Slide 6: This shows the current snowpack conditions for the 3 SNOTEL sites that we have for the basin. The plots show the 10-50-90 percentile levels of observed snowpack going back to 1950 along with the observed snowpack for the last 2 water years for reference. We currently have near-median conditions in terms of snowpack as evidenced by the red 2019 line staying fairly close to the middle black line.
Slide 7: This shows estimated soil moisture as produced by NIDIS. The graphic shows that soil moisture conditions for the state are below or well-below observed average conditions. Hydrologically, this has the potential impact of decreasing runoff for the basin.
Slide 9 & 10: These slides show drought graphics produced by NIDIS. Slide 9 shows that the basin is categorized as being in ‘Extreme Drought‘ condition while Slide 10 shows how historical droughts have evolved for the state.
Slide 11: This slide shows temperature and precipitation outlooks as generated by the NWS. These graphics suggest that the basin is likely to experience above average temperatures and below average precipitation in the short-term (40% chance of above average temps, 40% chance of below average precip) and in the immediate future (60% temp, 40% precip).