Have you ever wondered what you would see if you could see through water? Well you can stop wondering because side scan sonar is here! Side scan sonar is a system that was discovered in the 1960s. The sonar system produces 2-dimensional images and recordings of cross-sectional swaths of the benthic environment. It reflects acoustic signals from a sensor to the riverbed which creates a footprint of the underwater habitat known as the swath which is instantaneously displayed on the control head (LCD screen). With recent development side sonar can easily detect deferent substrates types (e.g. sand, cobble, rock, debris, etc.) and with the assistance of GPS we can detect their locations.

As part of my job as a DFP for the U.S. Fish and Wildlife Service in Fairbanks, Alaska I am creating an investigation plan to use side scan sonar to map the underwater habitat of the lower Chena River. The Chena river is a major tributary for Salmon fish migration however, in recent years with development occurring more frequently along the riverbanks, salmon populations have decreased from loss of habitat. Recent restoration efforts have taken place along some of the disturbed banks. Installment of root wads to support riverbanks and provide shelter to the salmon have been adapted as well as the creation of vegetation buffers of local native species to increase bank stability and to reduce pollutants. However, development impacts as well the restoration efforts at an underwater scale have never been monitored in the area. It is critical to monitor the underwater habitat before and after these restoration efforts to document the different treatments effectiveness.

New research regarding the underwater habitat of the lower Chena river will aid managers in making informed management decisions as well as developing long term monitoring protocols to be used in the lower Chena river and possibly other areas similar in habitat characteristics. The new research could also assist property managers and realtors in the decision of property locations and boundaries.

Agency: U.S. Fish and Wildlife Service

Program: Directorate Fellows Program

Location: Fairbanks Fish and Wildlife Conservation Office