348 



TABLE 1. SUMMARY OF CRiSP 1.4 MODEL ANALYSES 

 FOR IMPLEMENTATION OF A JOHN DAY POOL DRAWDOWN 



John Day Pool Operations Change* 

 Snake River Spring Chinool< Elevation 262.5 (Minimum Irrigation Pool) 



CRiSP. 1 .4 Model Operation Conditions to Elevation 257 (Minimum Operating Pooh 



Existing Smolt Transportation Program in Place, 

 1 993 Operations Scenario (About 2% of the 

 Snal<e-Columbia River Smolt Migration Passes 

 Through the John Day Pool) Average Water 

 Conditions. 



Total Percentage Increase in Smolt Survival <1% 



Below Bonneville Dam 



Draw Down to Spillway on 4 Snake 

 Reservoirs/Average Water Conditions/No 

 Smolt Transportation** 



Total Percentage Increase in Smolt Survival <1% 



Below Bonneville Dam with: 



1) FGE Reduction at John Day Dam, 70% to 50% 



2) No Increase in Predator Concentrations 

 or Other Mortality Factors 



Total Percentage Increase in Smolt Survival 1% 



Below Bonneville Dam with: 



1) No FGE Reduction at John Day Dam (Dam 



Intake Screen Modifications Successful) 



2) No Increase in Predator Concentrations 

 or Other Mortality Factors 



Source: Personal Communication with Jim Anderson, Center for Quantitative Sciences- Dept of 

 Rsheries, University of Washington, July 20, 1993, CRiSP.1 .4 Model Analyses for John Day 

 Pool Drawdown Operations. 



• Minimum Operating Pool (MOP) represents a 1 2 foot drawdown elevation from full pool 

 operations. 



** Critical assumptions for the Snake River drawdown scenario include low smolt mortality rates 

 for Snake-Columbia River reservoir/project passage, and no latent mortality for smolts 

 below Bonneville Dam due to the effects of cumulative resen/oir/project passage. 



