Latest Statement From Bureau or Reclamation 4-6-19
Please refer to Figure 1 for approximate projected flow timing and magnitude associated with next week’s flow event at Link River. Again, note travel time is approximate and the general timing and magnitude of these flows may vary substantially from that presented here given the dynamic nature of the approaching storm system.
Given the magnitude of possible Upper Klamath Lake net inflow currently forecasted through next week (possibly in excess of 8,000 cfs in a single day), projections indicate that flows meeting or exceeding the criteria for a surface flushing flow (6,030 cfs for 72 hours) are likely to be observed at Iron Gate Dam as a direct result of flood operation releases at Link River Dam (see Figure 1 below). As such, Reclamation is currently directing PacifiCorp to operate to the Upper Klamath Lake flood control elevations and is not requesting any additional releases above those necessary for flood control operations from Link River Dam at this time.
Reclamation will continue to monitor the storm timing and magnitude and may need to provide additional guidance to PacifiCorp over the weekend or early next week. For instance, if the storm comes in lighter than expected, Reclamation may need to direct PacifiCorp to increase Link River Dam releases to meet minimum surface flushing flow criteria at Iron Gate Dam if flood operation releases at Link River Dam would otherwise be less than the volume or duration required for surface flushing flows. Conversely, if the storm comes in heavier than expected, it may be necessary and prudent to increase Link River Dam releases above those specifically required by the flood control curve to create additional storage space in Upper Klamath Lake to prepare for additional projected high inflows. Reclamation’s commitment is to balance the opportunity to produce a higher volume (deep) flushing flow with public safety and property concerns associated with the uncertainty of the overall system’s response to unpredictable and spatially variable runoff resulting from large storms.
In summary, Reclamation is still evaluating maximizing releases at Link River Dam; however, PacifiCorp expressed serious concerns about potential downstream flooding at flows greater than 9,000 cfs below Iron Gate Dam. At this time, due to safety concerns, Reclamation is not requesting explicit implementation of an 11,250 cfs flow at Iron Gate Dam (a deep flushing flow), or maximum releases from Link River Dam if not otherwise necessary for flood operations. While Reclamation is not directing PacifiCorp to take any action outside its “general” flood control operations, should Reclamation determine that hydrologic conditions and public safety make a “deep flushing flow” feasible, Reclamation will so notify PacifiCorp as to the specifics of that operation with due consideration to river conditions downstream of Iron Gate Dam.
Figure 1. Projected flow timing and magnitude associated with next week’s flow event at Link River (orange line), Keno (blue line), and Iron Gate (gray line) dams. Note that travel time is approximate and that the general timing and magnitude of these flows may vary substantially from that presented here given the dynamic nature of the approaching storm system.