Coastal Habitats in Puget Sound (CHIPS)

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Restoration of Large River Deltas

Task Overview

Map showing location of Skagit River Delta. Map showing Skagit River delta and its habitats

Map of the Skagit River delta shows examples of disturbance of critical shore habitat associated with river channelization and diking. [Larger version]

The Skagit Delta/Whidbey Basin Ecosystem

Deltas serve many ecological purposes, including estuarine habitats for fish and wildlife. But during the past 150 years, 70 to 80 percent of the marshes and wetlands of Puget Sound have been lost. These changes reflect human impacts associated with a variety of agricultural and residential activities that have ultimately altered streamflows, transport of coastal sediments, water quality, and a myriad of other processes that are responsible for habitat creation, maintenance, and biological productivity.

In the Skagit River delta, activities such as damming, diking, land clearing, draining, deforestation, and agriculture have caused significant changes in lowland habitat. In addition to habitat losses, existing margins of the coastline have lost their connections to other areas through ecosystem fragmentation created by physical barriers and altered tidal flows.

Current work is centered on the ecology of eelgrass beds and other coastal and wetland habitats. Investigators are compiling and evaluating historical information and collecting baseline data about sediment transport and other hydrographic processes to help characterize the physical and biological environments of the Whidbey Basin nearshore. The importance of coastal habitats to endangered Chinook salmon and bull trout are a special focus of biological study.

photo of fish in eelgrass

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U.S. Department of the Interior | U.S. Geological Survey
Page Contact Information: USGS Pacific Coastal and Marine Science Center
Page Last Modified: Friday, 06-Oct-2017 14:58:29 EDT