Regulating the timing and volume of water released from storage reservoirs (often referred to as flow augmentation) has become a central mitigation strategy for improving downstream migration conditions for juvenile salmonids in the Snake River. The success of flow augmentation in turn depends on releasing reservoir waters when and where wild smolt will benefit the most. This requires the ability to predict in real time the status and trend in the outmigration of listed threatened and endangered stocks.

The RealTime Forecasters use historical PIT Tag detections or Passage Indices to assist the inseason Technical Management Team (TMT) in the management of Columbia River hydrosystems operations for juvenile fish passage. The RealTime Forecasters use pattern recognition techniques to predict the percent of the run-to-date and days to a specific percent of the run. The statistical algorithms smooth historical trends in PIT tag arrivals or passage indices and use a generalized weight least squares decision criterion in making predictions.

Current Application of RealTime Forecasters

• Inseason Migratory Forecasts - Predicts the arrival distributions of stocks of outmigrating juvenile salmon at several monitoring sites along the Snake and Columbia Rivers. The tool uses "real time" information about the current status of the runs along with current hydrographic information to predict the future progress of the migrating fish. This is a joint effort of the RealTime and CRiSP1 models. RealTime Forecasters has generated and distributed web-based inseason migratory forecasts for Columbia Basin juvenile salmonid stocks since 1996.

RealTime Forecasters Performance

• Inseason Forecasts and Related Publications - Post season analysis of program RealTime Forecaster performance for 1994 to the present.

Passage Prediction Graph (Cumulative Passage)

Daily Record Graph

Passage Prediction with Historical Timing Plot