Abstract Title

Session S-01G: New Strategies for Shorelines

Proposed Abstract Title

Puget Sound Feeder Bluff Mapping: Compiling and completeing a Sound-wide geomorphic data set

Keywords

Shorelines

Location

Room 6C

Start Date

1-5-2014 5:00 PM

End Date

1-5-2014 6:30 PM

Description

The term “feeder bluff” is used in the Puget Sound region to describe bluffs that provide a significant volume of sediment to the beach. Beaches and spits, sustained by the ongoing supply of sand and gravel from feeder bluffs, are key elements in the Puget Sound nearshore ecosystem. The objective of this project was to produce comprehensive mapping of Puget Sound feeder bluffs and related coastal landforms suitable for guiding improved shoreline management. In recent years, different mapping efforts conducted in the region have attempted to integrate general principles and concepts of coastal geomorphology. Coastal Geologic Services (CGS) developed a mapping method, in collaboration with a technical advisory group consisting of local coastal processes experts, which had been applied across 11 counties and over 1,150 miles of Puget Sound shore (Johannessen and Chase 2005, Johannessen 2010). However, neither this method nor any other which sufficiently addressed these principles had been applied across Puget Sound. Several previous Sound-wide mapping efforts fell short either due to coarse resolution, frequent errors, or by being focused only on the mapping of coastal landforms rather than morphology and processes. The CGS team compiled 26 data sets to characterize and evaluate how feeder bluffs or similar landforms were mapped. The relative quality of data was assessed to identify consistencies and differences among the data sets, and identify the best quality data for inclusion (with minor revisions if necessary) into an interim geodatabase of existing feeder bluff mapping. Ten existing data sets (700 miles of shore) met the assessment criteria and formed the foundation for the final feeder bluff mapping geodatabase. The remaining unmapped shores determined the areas in which new mapping would focus. Most new mapping was conducted using a field-based approach, with some remote mapping (approximately 22% of new mapping). The mapping methods applied were the same as those applied by CGS across approximately half of the Puget Sound region shore. All data were compiled and analyzed to enhance understanding of the occurrence of feeder bluffs and other geomorphic shoretypes throughout the Puget Sound region. Shoretype data were analyzed Sound-wide, within each drift cell, and within each county, to support county-wide shoreline management. Data assessment, compilation, and new data collection have resulted in a high-quality, comprehensive, geomorphic data set spanning the Puget Sound region. This data set documents regional variability in nearshore geomorphic conditions, forms a foundation for future coastal geomorphic research, and will enhance greater understanding of geomorphic processes in the region over time.

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May 1st, 5:00 PM May 1st, 6:30 PM

Puget Sound Feeder Bluff Mapping: Compiling and completeing a Sound-wide geomorphic data set

Room 6C

The term “feeder bluff” is used in the Puget Sound region to describe bluffs that provide a significant volume of sediment to the beach. Beaches and spits, sustained by the ongoing supply of sand and gravel from feeder bluffs, are key elements in the Puget Sound nearshore ecosystem. The objective of this project was to produce comprehensive mapping of Puget Sound feeder bluffs and related coastal landforms suitable for guiding improved shoreline management. In recent years, different mapping efforts conducted in the region have attempted to integrate general principles and concepts of coastal geomorphology. Coastal Geologic Services (CGS) developed a mapping method, in collaboration with a technical advisory group consisting of local coastal processes experts, which had been applied across 11 counties and over 1,150 miles of Puget Sound shore (Johannessen and Chase 2005, Johannessen 2010). However, neither this method nor any other which sufficiently addressed these principles had been applied across Puget Sound. Several previous Sound-wide mapping efforts fell short either due to coarse resolution, frequent errors, or by being focused only on the mapping of coastal landforms rather than morphology and processes. The CGS team compiled 26 data sets to characterize and evaluate how feeder bluffs or similar landforms were mapped. The relative quality of data was assessed to identify consistencies and differences among the data sets, and identify the best quality data for inclusion (with minor revisions if necessary) into an interim geodatabase of existing feeder bluff mapping. Ten existing data sets (700 miles of shore) met the assessment criteria and formed the foundation for the final feeder bluff mapping geodatabase. The remaining unmapped shores determined the areas in which new mapping would focus. Most new mapping was conducted using a field-based approach, with some remote mapping (approximately 22% of new mapping). The mapping methods applied were the same as those applied by CGS across approximately half of the Puget Sound region shore. All data were compiled and analyzed to enhance understanding of the occurrence of feeder bluffs and other geomorphic shoretypes throughout the Puget Sound region. Shoretype data were analyzed Sound-wide, within each drift cell, and within each county, to support county-wide shoreline management. Data assessment, compilation, and new data collection have resulted in a high-quality, comprehensive, geomorphic data set spanning the Puget Sound region. This data set documents regional variability in nearshore geomorphic conditions, forms a foundation for future coastal geomorphic research, and will enhance greater understanding of geomorphic processes in the region over time.