In the 1990?s, CTUIR and ODFW along with many other agencies began implementing fisheries restoration activities in the Walla Walla Basin. An integral part of this effort, as outlined in Section 7.11B of the 1994 Fish and Wildlife Program, is to alleviate the inadequate migration conditions in the basin. Fish populations in the Walla Walla River have been heavily impacted by inadequate passage facilities at diversions and resultant dewatering associated with agricultural demands and are a primary factor in the decline of native summer steelhead runs and extirpation of spring chinook salmon in the basin. The Passage Improvements Project goal is to assist in the restoration of salmonid populations in the Walla Walla Basin by increasing adult and juvenile migrant survival. The project provides survival benefits for migrating juveniles and adults by removing passage barriers, improving fish ladders and canal screens, and operating and maintaining passage facilities. This project will integrate with other fisheries restoration activities in the basin by addressing passage issues imperative to the continued survival and reintroduction of salmonid fish within the basin. It is expected that by providing safe passage to juvenile and adult salmonid fish, naturally spawning populations of salmonids will be elevated, and juvenile outmigration increased. The Walla Walla River is heavily diverted for agricultural use. There are two major irrigation diversions located in the mid Walla Walla River at river miles 36 and 47, along with numerous smaller diversions. Historically, inadequate flow and passage conditions during critical portions of both adult and juvenile migration periods was the primary contributor to the extirpation of salmon and decline of summer steelhead and bull trout populations in the Walla Walla Basin. Unscreened or inadequately screened irrigation canals and inadequate passage at diversion structures played key roles in the decline of the basin fish populations. Inadequate screening resulted in the irretrievable loss of juveniles down irrigation canals or from impingement injury due to improper screen criteria. Non-existent or improper juvenile bypasses and adult ladders caused migration barriers or delays and injury. Over the last few years, this project has begun to address these passage concerns. Two decommissioned diversion dams have been removed to provide better upstream passage conditions. Modern fish screen systems have been built at the two major irrigation canals and at a few smaller diversions to protect downstream migrants. Juvenile bypasses and adult ladders have also been constructed to provide better passage conditions. Passage experts from NMFS, USFWS, WDFW, ODFW, and CTUIR participate in the planning and design of these facilities and incorporate current NMFS passage criteria guidelines. It is assumed that these efforts provide more adequate passage conditions and increase survival for both migrating juveniles and adults. Now that these passage improvement efforts have been initiated, it is important that long term operation and maintenance occur in order to maintain the survival advantages achieved by their implementation. Improvement of passage conditions has been identified in the Subbasin Summary, as well as every other Walla Walla Basin planning document, as a critical component in the restoration effort for salmon and steelhead by ensuring that passage conditions are no longer a limiting factor. In addition to the subbasin planning documents (referenced in Section 9.h.), the Council, in Section 7.11B of the 1994 Fish and Wildlife Program, identified tributary passage enhancement efforts as necessary to restore fish populations such as those in the Walla Walla Basin. Inadequate passage conditions for both upstream and downstream migrants were a primary contributor to the extirpation of salmon and decline of steelhead in the Walla Walla Basin. Although many passage improvements have b
