Student: Austin Halstead
Mentor: Lisa Ely
The Yakama Nation’s Yakima-Klickitat Fisheries Project (YKFP) and Mid-Columbia Fisheries Enhancement Group (MCF) placed large logs and woody debris along a 1.5 km stretch of the North Fork Teanaway River channel and floodplain in the summer of 2019. Historically, large woody debris was common in the Teanaway River. The purpose of the current wood emplacement is to maintain and restore natural river processes and enhance aquatic habitats. Adding woody debris increases channel complexity, which helps fish by creating spawning areas, scouring pools and lowering water temperature, increasing food availability, and reconnecting floodplains to the river. During the winter of 2020, I georeferenced aerial photographs and drone images from 1954, 1978, 1998 and 2019 to document changes in the Teanaway River over time in the area of the large wood restoration. I outlined and overlaid the channel positions from each time period in ArcGIS Pro, and created topographic cross sections of the channel and floodplain. The greatest changes were between 1954 and 1998. The stream channel notably migrated laterally from the 1954 to 1978 aerial photos, and again from 1978 to 1998. There appears to be a general increase in vegetation along the side of the channel over the study period, which could partially explain the decreased rate of channel change in the last two decades. With the addition of large woody debris to the sides of the channel, the flow of the main channel will slow, and the water may seek alternative/additional routes, possibly in the previously abandoned channels.