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d. For flows above 8,000 cfs to 2$,000 cfs, the spillway • will carry the majority of the riverflow with approximately 1 foot of freeboard allowed at the maximum flow. The ladder itself will be over- topped, also passing a portion of the floodflow. e. For standard operational conditions, auxiliary water is added at the fish entrance. Ths diffuser and entrance are similar to Alternate No. 1 and the design quantity of available auxiliary water is 25 cfs. 3. Operational Flexibility. a. Two lightweight weir boards could be removed to form 8-foot-wide by 20-foot-long pools. The result of this modified design is a 1-foot head drop per pool, ladder flow of approximately 25 cfs, and available auxiliary flow of 25 cfs. At high tailwater, the head drop will vary from 0.35 foot at the downstream end of the ladder to only 0.60 foot at the junction pool. If the 1-foot head drop is desired at high tailwater, ladder flow would be 43 cfs. b. Weirs could be installed to form 8-foot-wide by 5-foot- long pools. The result of this modified design is a 0.25-foot head drop per pool, ladder flow of approximately 12.5 cfs, and available design auxiliary flow of 25 cfs. At high tailwater, the head drop will be about 0.10 foot per pool from the downstream end to the junction pool. If the 0.25-foot head drop is desired at high tailwater, the ladder flow would be 22 cfs. 4. Other Considerations. a. Biological and Technical Considerations. 1. The horizontal and vertical placement of the fish- way entrance is the same as for Alternate No. 1. The location has been set to attract the two target species into the fish ladder with the proper sluice gate flow conditions and the auxiliary attraction water. 2. The interior configuration of the ladder is similar to Alternate No. 1 and should be compatible with the swimming abilities and preferences of the two target species. • 24