Presentation Abstract
Much of Puget Sound’s shoreline consists of mixed sand and gravel beaches, dominated by longshore sediment transport and organized into hundreds of discrete littoral cells. Sediment supply within these cells is often provided by erosion of the steep coastal bluffs, which are composed of abundant, coarse-grained Pleistocene sediment. Bluffs that provide beach sediment are referred to as feeder bluffs and are important to the long-term maintenance of Puget Sound beaches. At the same time, development of Puget Sound’s shoreline has led to widespread construction of seawalls and revetments to control bluff erosion, with the unintended consequence of reducing natural sources of beach sediment. Coastal managers are concerned that this will adversely impact beach conditions. Impair nearshore ecological functions, and reduce resilience to rising sea level. Until recently, regional mapping of feeder bluffs existed. In 2012-2013, we combined existing information with new data and completed a sound-wide coverage of eroding bluffs, along with related beach and coastal landforms. Mapping was conducted using detailed field observations, supplemented with geologic information and aerial photographs. Bluffs were categorized based on their potential ability to deliver beach sediment. We found that of Puget Sound’s 4000 km of shoreline, about 2200 km are beaches. Of these about 600 km are feeder bluffs and about 50 km were mapped as exceptional. About 35% of the region’s beaches were mapped as modified or armored. The maps of feeder bluffs will be provided on Ecology’s online Coastal Atlas, allowing access and integration with other nearshore data. In addition, web-based material provides background information on geology and beaches and guidance on how to interpret and apply his information. This will assist planners and resource managers in improving shoreline management, assessing Puget Sound nearshore health, and identifying coastal restoration priorities.
Session Title
Session S-01G: New Strategies for Shorelines
Conference Track
Shorelines
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
30-4-2014 10:30 AM
End Date
30-4-2014 12:00 PM
Location
Room 6E
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Beach erosion--Washington (State)--Puget Sound; Coastal zone management--Washington (State)--Puget Sound; Shore protection--Washington (State)--Puget Sound; Shorelines--Washington (State)--Puget Sound
Geographic Coverage
Puget Sound (Wash.); Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Included in
Feeder Bluffs on Puget Sound: Tools for Improved Management
Room 6E
Much of Puget Sound’s shoreline consists of mixed sand and gravel beaches, dominated by longshore sediment transport and organized into hundreds of discrete littoral cells. Sediment supply within these cells is often provided by erosion of the steep coastal bluffs, which are composed of abundant, coarse-grained Pleistocene sediment. Bluffs that provide beach sediment are referred to as feeder bluffs and are important to the long-term maintenance of Puget Sound beaches. At the same time, development of Puget Sound’s shoreline has led to widespread construction of seawalls and revetments to control bluff erosion, with the unintended consequence of reducing natural sources of beach sediment. Coastal managers are concerned that this will adversely impact beach conditions. Impair nearshore ecological functions, and reduce resilience to rising sea level. Until recently, regional mapping of feeder bluffs existed. In 2012-2013, we combined existing information with new data and completed a sound-wide coverage of eroding bluffs, along with related beach and coastal landforms. Mapping was conducted using detailed field observations, supplemented with geologic information and aerial photographs. Bluffs were categorized based on their potential ability to deliver beach sediment. We found that of Puget Sound’s 4000 km of shoreline, about 2200 km are beaches. Of these about 600 km are feeder bluffs and about 50 km were mapped as exceptional. About 35% of the region’s beaches were mapped as modified or armored. The maps of feeder bluffs will be provided on Ecology’s online Coastal Atlas, allowing access and integration with other nearshore data. In addition, web-based material provides background information on geology and beaches and guidance on how to interpret and apply his information. This will assist planners and resource managers in improving shoreline management, assessing Puget Sound nearshore health, and identifying coastal restoration priorities.
