Feasibility Study for Evaluating Redistribution of Juvenile Salmon in the McNary Bypass Channel Using Behavioral Technologies: 1996.
Abstract
Evaluation of behavioral technologies to redistribute juvenile salmon in dewatering sections of a bypass channel encompassed two study years. The first year (Fiscal Year 1996) was preliminary and focused on two objectives: (a) characterizing the acoustic environment in selected areas of the McNary bypass channel; and (b) evaluating the feasibility of using video cameras to image salmon smolt in the McNary channel. We characterized underwater sound fields by measuring sound pressure and structural vibration in September 1996. High sound pressure levels at frequencies less than 24 Hz were observed at all sampled locations. The measuring sound pressure levels (1702 dB referenced to 1 muPa) were in the frequency range 0.125 to 1 Hz. Within the 1- to 24-Hz frequency range, the distribution of infrasound observed in the channel exhibited a pattern with most of the highest readings occurring in the transition between the concrete lining and the discharge duct and reduced readings near the water level indicator. Additionally, sound pressure levels measured at two depths per station were observed to decrease toward the surface. Substantial vibration of the channel lining was observed at frequencies less than 24 Hz. During spring and summer of 1996, we examined the feasibility of using infrared-sensitive underwater cameras to image smolt passage in the bypass channel. Results indicate that infrared lights and underwater cameras can effectively image smolts in the channel but visibility is limited to approximately 0.91 m. We tested different lighting schemes and found forelighting to be most effective for imaging smolt-sized targets. We compared time-lapse with real-time recording and determined the former to he ineffective due to the reduced number of framed images captured in the high flows of the McNary channel.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1998
- Accession Number
- ADA357962
Entities
People
- Gene R. Ploskey
- Jim Evans
- John M. Nestler
- Peter N. Johnson
- Thomas J. Carlson