Before it’s river sediment: hillslope geomorphology and processes

Members of the UO river research group have been busy thinking about the ways rocks and soil move across the landscape before ending up as river channel sediment this autumn by attending field trips as part of Hillslope Geomorphology being taught by Josh Roering in the UO Geological Sciences department. Aaron Zettler-Mann, Christina Appleby, and Devin Lea all traveled as part of the class in October to the Painted Hills Unit of the John Day Fossil Beds National Monument to measure and analyze hillslope processes occurring on the area’s badland topography. This trio, headed by Aaron, also obtained photographs and created a high-resolution DEM of the study area using structure-from-motion. Aaron and Devin more recently traveled with the class in early November to the Oregon Coast Range to study a series of debris flows that occurred on the Wolf Creek watershed in 2012. Understanding the failure rate and mechanisms of these debris flows are important for hazard risk assessments, landscape development over time, and how and when sediment is delivered to rivers.

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Students ponder badland processes at the Painted Hills

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Photographs taken at the Painted Hills were used to generate a high-resolution DEM

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A great example of valley fog on the way to examine debris flows in the Oregon Coast Range

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Devin and Aaron helped measure the site of initial failure for a debris flow on a nearly 40 degree hillslope in the Coast Range

Field Trip to Mount Hood and Columbia River Gorge

A group of students from Mark Fonstad’s seminar, the Physical Geography of Oregon, took a field trip in late October to various sites around Mt. Hood and the Columbia River. We drove around the south and east side of Mt. Hood to learn about its lava domes and lahar and debris flows, such as the debris flows at White River. One of the students flew his recreational UAV to capture video and photography of this quickly changing river to later analyze using structure-from-motion. We observed forest composition changes as we made our way to the Parkdale Lava Flow on the northeast side of Mt. Hood. We hiked at Tamanawas Falls, drove along the Washington side of the Columbia River to view the Oregon side of the gorge, and ended our day at Multnomah Falls before returning to Eugene.

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White River, Mt. Hood
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near Parkdale lava flow, Mt. Hood
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Multnomah Falls
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hike at Tamanawas Falls

 

Tamanawas
Tamanawas Falls