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

COinS
 
Apr 30th, 10:30 AM Apr 30th, 12:00 PM

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.