Event Title
West Whidbey Island beach and bluff change between 2015, 2018, and 2021 from boat-based lidar
Streaming Media
Presentation Abstract
The Washington State Department of Ecology Coastal Monitoring & Analysis Program (CMAP) collected high-resolution coastal topographic data along west Whidbey Island with boat-based lidar in 2015, 2018, and 2021. The high-density data acquired along the beach and bluff enabled detailed measurements of morphology and the generation of 0.5-meter digital elevation models (DEMs). The overlap between all three datasets, from Point Partridge north to West Beach County Park, is a 9-km reach dominated by feeder bluffs along the updrift end of a 23-km drift cell with relatively high wave exposure. The DEMs are compared along this updrift reach to reveal patterns of bluff erosion, sediment supply, and beach change over the six years between surveys. This represents the first opportunity to estimate both short- and mid-term sediment budgets with transport rates inferred from morphology change. Additional insight to sediment transport processes is provided by sediment grain-size data that were also collected during the surveys. Localized rates of bluff retreat inform planning and decision-making for bluff-top development on a parcel-by-parcel basis, and help landowners understand their erosion risks.
Session Title
Poster Session 3: Land - Water Connections
Conference Track
SSE14: Posters
Conference Name
Salish Sea Ecosystem Conference (2022 : Online)
Document Type
Event
SSEC Identifier
SSE-posters-387
Start Date
27-4-2022 4:00 PM
End Date
27-4-2022 4:30 PM
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
West Whidbey Island beach and bluff change between 2015, 2018, and 2021 from boat-based lidar
The Washington State Department of Ecology Coastal Monitoring & Analysis Program (CMAP) collected high-resolution coastal topographic data along west Whidbey Island with boat-based lidar in 2015, 2018, and 2021. The high-density data acquired along the beach and bluff enabled detailed measurements of morphology and the generation of 0.5-meter digital elevation models (DEMs). The overlap between all three datasets, from Point Partridge north to West Beach County Park, is a 9-km reach dominated by feeder bluffs along the updrift end of a 23-km drift cell with relatively high wave exposure. The DEMs are compared along this updrift reach to reveal patterns of bluff erosion, sediment supply, and beach change over the six years between surveys. This represents the first opportunity to estimate both short- and mid-term sediment budgets with transport rates inferred from morphology change. Additional insight to sediment transport processes is provided by sediment grain-size data that were also collected during the surveys. Localized rates of bluff retreat inform planning and decision-making for bluff-top development on a parcel-by-parcel basis, and help landowners understand their erosion risks.
