A Half Century of Channel Changes in the North Fork Teanaway River at a Large Wood Restoration Site

Student: Austin Halstead

Mentor: Lisa Ely

Abstract

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.

Presentation

8 thoughts on “A Half Century of Channel Changes in the North Fork Teanaway River at a Large Wood Restoration Site”

  1. Nice Presentation. Do you think humans could have had something to do with the change as they were in the area at the time?

    1. Yes, I think humans could have done many things to alter the natural movement of the river. Especially considering that the previous owners of the land were timber companies. For example, this I think is the reason why there is so much more vegetation along the river now then there were in the older photos. Now the area is no longer being cleared every so often of vegetation, so it has been able to establish itself. Slowing the erosion of the banks, slowing the movement of the river channel.

  2. Nice work, Austin! You should share these results with the organizations who are placing the wood into the Teanaway, I’m sure that they will be interested.

  3. Great presentation Austin! It was very interesting. I felt like I could relate it to the environment and river systems back home.

  4. Hi Austin,
    You made a fine presentation and illustrated it well! It clearly represent a lot of time and effort. You have left me interested in a minor detail. Do you have any idea of the age of the river terrace?
    Thank you,
    Jim

    1. Hi Jim,
      I do not know the age of the river terrace, as that fell a little to far outside of my projects’ scope, but I would like to know how old it is as well.

      1. Austin,
        I understand, it was just a long shot. Prof. Ely has me interested in river terraces, among other things, so I was just curious. By the way, you have a very clear and confident voice for presentations. I wish you the best as you use that in your career(s)!
        Jim

  5. Really great work, Austin! It’s nice that you were able to combine GoogleEarth techniques with ArcGIS techniques for this project. My MS thesis is quite similar to your project, except I am looking at how large wood has been redistributed over time in the Elwha River after a dam removal, and how this is changing the channel morphology/sedimentation.

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