Imaging smolt behavior on bypass screens and a vertical barrier screen at McNary Dam in 1992. Final report

Duing the spring and summer of 1992, video imaging of smolt bypass systems at McNary Dam on the Columbia River was conducted using low-light sensitive underwater video cameras to record smolt behavior and impingement characteristics on a modified balanced flow vertical barrier screen (MBFVBS), a standard-length submerged uavehng screen (SSTS), and an extended-length submerged bar screen (ESBS). The cameras on the ESBS recorded smolt behavior to three closure gate settings, two screen positions, three discharges, two screen angles, and presence/absence of a fyke net. The cameras on the SSTS recorded smolt behavior only at the standard deployment settings. Cameras on the MBFVBS recorded smolt behavior to four unit loads and three closure gate settings. A variety of hydraulic and behavioral data were collected from each recorded image for the bypass screens. Data from physical model studies were used to supplement imaging data for some design or deployment configurations. For the bypass screens, hydraulic data included direct measurements of water approach angle relative to the screen surface. Behavioral data collected included descriptions of the approach of the smolt to the screen (i.e., angle of approach, angle of retreat after a strike, orientation of the fish in the water) and descriptions ofmore » entrainment and impingement of smolts on the screen (e.g., entrainment without strike or impingement, strike with escape, impingement without escape, head-first approach without strike or impingement, and head-first approach with impingement). The video imaging demonstrated that direct imaging of smolt behavior in the different parts of a bypass system can provide valuable information on the effects of different screen designs or deployment configurations.« less