Physiography

Physiography and Regional Influences

From the mountains to the sea, the northern Puget Sound watershed offers a rich contrast in wildlife and scenery. To set the stage for describing the physical environment, this section highlights the geographic and physiographic features that define northern Puget Sound at varying spatial scales.

Physiography is "physical geography, the study of the natural features of the earth's surface, including landforms, oceans, seas, soils, atmosphere, and the distribution of fauna and flora".1 Contrasts in the physiography of the northern Puget Sound watershed are a defining feature of the area. These contrasts are present at geographic scales, ranging from the Western Cascades to the Salish Sea, and make the region an "edge area" where margins of two separate communities of vegetation meet.2

Project Area

NPSEC Project Area (click image for detailed view)

The project area for the Northern Puget Sound Ecological Characterization (NPSEC) is comprised of the Strait of Georgia, Nooksack River, and San Juan Island watersheds delineated by their Hydrologic Unit Code (HUC) numbers 17110002, 17110004, and 17110003 respectively. It is bounded on the north and west by the international boundary with British Columbia, Canada. The North and South Forks of the Nooksack River bound it on the east. It is bounded on the south by the northern border of the Puget Sound watershed (HUC code 17110005). The notch along the northern boundary is the Sumas watershed that drains north to British Columbia, which is not included in this project area. The intention in delineating these boundaries is to capture the freshwater inputs and marine waterbodies of northern Puget Sound.

The project area is located in the state of Washington and includes all of San Juan County as well as portions of Whatcom and Skagit counties. The project area is approximately 77 miles from east to west and approximately 40 miles north to south and encompasses some 2,315 square miles. The largest urban area is the city of Bellingham (pop. 80,000), located in the center of the project area. Bellingham is approximately 90 miles north of the metropolitan area of Seattle and approximately 70 miles south of the metropolitan area of Vancouver, British Columbia.

Terrestrial elevation change within the project area ranges from Mt Baker (10,778 feet) to sea level (0 feet). Marine bathymetry is referenced from Mean Lower Low Water (MLLW) and ranges from +12 feet MLLW to -600 feet (100 fathoms) MLLW.

Major freshwater influences to the project area include the Fraser River from the north in British Columbia and the Nooksack River that discharges to Bellingham Bay. Minor freshwater influences include Dakota and California Creeks in Whatcom County and the Samish River in Skagit County.

References Cited

1. Merriam-Webster Inc. 1990. Webster's Dictionary. Merriam-Webster. Springfield, Mass.

2. Stevenson, L. H. and B.Wyman. 1991. The Facts on File Dictionary of Environmental Science. Facts On File. New York.