ESTIMATING STREAMFLOW METRICS ON SUBSISTENCE STREAMS USING TIME-LAPSE CAMERAS (Invited Presentation)

Rivers are a conduit for life, and streamflow data from gauge stations provide insight into rivers' physical and ecologic functions. However, barriers such as remote locations, rugged terrain, and costs are often prohibitive for the installation of stream gauge stations. This is true for the remote region of Southeast Alaska, resulting in a lack of streamflow data for the region. Southeast Alaska, located on Lingít Aaní, is composed of the world's largest temperate rainforest and can receive over 1500 mm of precipitation annually. This precipitation fuels over 900 watersheds, most of which are ungauged, that provide subsistence, economic, and recreation opportunities for local residents and visitors. To address the paucity of streamflow data in Southeast Alaska, this study tests the efficacy of using game cameras as a more cost-effective and holistic data collection method. Three monitoring stations were installed in important subsistence rivers for the communities of Sitka and Hoonah, Alaska, with assistance from the Sitka Tribe of Alaska and the Hoonah Indian Association. Each monitoring station consists of a Reconyx HyperFire 2 game camera and two Onset HOBO Water Level Data Loggers (pressure transducers). Game cameras and pressure transducers collected data every hour during daylight hours, and every 15 minutes, respectively, between July 2022 and September 2022 Neural network models were developed to relate stage height data, calculated from the pressure transducers, and game camera images. Specifically, this machine learning technique identifies the water's edge line for given flow conditions, producing information similar to stage height. In addition to being a more cost-effective method, this data collection technique provides the opportunity for collecting other streamflow metrics such as biomass and substrate movement, hydrologic connectivity, and a visual representation of flow events. Together this information is crucial for regions like Southeast Alaska whose identity is closely connected to the rivers that provide habitat for salmon, fuel hydropower generation, nourish the flora and fauna, and in short provide a way of life.