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18-10 Prioritizing Floodplain Reconnection in the Pacific Northwest to Support Municipal Drinking Water Management Post-Wildfire

Session: Shaping a Sustainable Future with Geology in the Twenty-First Century: Geology and Society Division Turns 22

Presenting Author:

Emily Smoot

Authors:

Smoot, Emily E¹, Flitcroft, Rebecca L², Santelmann, Mary V³, Shukla, Tanya⁴, Tullos, Desiree D⁵, Lancaster, Stephen T⁶

(1) College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA, (2) Pacific Northwest Research Station, US Department of Agriculture, Forest Service, Corvallis, OR, USA, (3) College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA, (4) Biological and Ecological Engineering, Oregon State University, Corvallis, OR, USA, (5) Biological and Ecological Engineering, Oregon State University, Corvallis, OR, USA, (6) College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA,

Abstract:

Across the western United States, wildfires are becoming more frequent and burning with greater intensity owing to the combined effects of altered patterns of precipitation and temperature, as well as historic forest management practices. Increased wildfire occurrence and severity may also increase post-fire impacts, such as soil erosion, habitat loss, and infrastructure damage. These post-fire impacts have the potential to increase fine sediment delivery to municipal drinking water intakes. Lateral floodplain reconnection may mitigate some of the impacts of increasing wildfire activity, enhancing ecosystem functions by restoring habitat, storing mobilized sediments post-wildfire, and providing wildfire refuge and firebreaks for animals. We present a reconnection priority index that includes nearly 3000 HUC12 subbasins in Oregon and Washington to determine potential areas where floodplain reconnection projects are likely to produce the greatest storage of post-wildfire sediment pulses. We conducted a spatial query of SSURGO data to identify potential floodplain reconnection areas. Then, we employed an indexing approach to prioritize reconnection opportunities while maintaining the ability to discreetly interpret individual components. The indexing combined available reconnection areas with pre-fire sediment sources, human alteration metrics, and potential wildfire severity. Preliminary results highlight 366 subbasins and suggest that floodplain reconnection opportunities will provide the greatest mitigation of wildfire-derived sediment loads if they are prioritized in agricultural zones disconnected by levees with limited development. Results contribute to the development of approaches for spatial prioritization of nature-based solutions, specifically lateral reconnection, and provide a starting point for managers when surveying areas for future reconnection projects.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10132

Prioritizing Floodplain Reconnection in the Pacific Northwest to Support Municipal Drinking Water Management Post-Wildfire

Description

Session Format: Oral

Presentation Date: 10/19/2025

Presentation Start Time: 10:30 AM

Presentation Room: HBGCC, 302B

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