NEHALEM WATERSHED (Site Overview)

Watershed Overview

 

The Nehalem watershed is one of the larger watersheds on the Oregon coast. The mainstem of the Nehalem River is 105 miles long and its drainage area is 855 square miles (544,450 acres). There are a total of 894 miles of major streams in the Nehalem watershed and 23% have anadromous fish present (NRCS 2005). The watershed crosses several county boundaries including Clatsop (39% of watershed), Columbia (30%), Tillamook (25%), and Washington (6%) counties. It is crossed by several highways including Highways 101, 26, 53, and 47 (see Map #1).

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Map 1 Watershed Overview

The watershed has three main population centers, the towns of Vernonia, Wheeler, and Nehalem. The 2009 combined population of these areas was 3,009 people (US Census Bureau 2010). Other citizens live outside of these main population centers. The average median income for the towns is around $38,000 and 42% of jobs are in educational/social/health care services and manufacturing. Agriculture, forestry, fishing/hunting, and mining account for 9% of the jobs in the towns and 5% in the counties (not including Washington County since it includes much larger urban areas in the Willamette Valley).

The watershed is quite diverse ranging from sea level to 3,640 ft. The topography separates the watershed into distinct western (lower) and eastern (upper) portions. The highest peak, Buck Mt., is located in the south/central portion of the watershed and influences rainfall patterns with the western portion receiving annual average precipitation of 90-200 inches while the eastern portion averages less than 65 inches. These elevation and rainfall patterns have an influence on the type of vegetation that occurs as does the proximity to the coast (Franklin and Dyrness 1988). In the wetter coastal areas, temperate rainforest composed of Sitka spruce and Western hemlock dominates. In the eastern half, Douglas fir/Western hemlock forest is better adapted with a few Pacific silver fir forest communities found in higher elevations. Portions of these forests burned during the series of wildfires known as the Tillamook Burns, which occurred from about the 1930s-1950s. Unique mountain bald grassland communities are found on the tops of peaks that occur on basalt rocks formed from lava that flowed down the Columbia to the coast.

According to interpretation of General Land Office Surveys from the late 1800s (Hawes et al. 2002), the lower Nehalem River estuary areas were covered by extensive Sitka spruce swamps and salt marsh, with smaller areas of shrub swamp and coastal sphagnum bog. The Nehalem spit was covered by open sand dunes with shore pine forest in the uplands and coastal prairie along the coastal bluffs. Along the mainstem of the river above tidal influence, riparian Sitka spruce forests were abundant as were wet and dry prairie habitats. Oak savannah is reported in areas of the upper watershed[1]. Ash swales are an important wetland type in the upper watershed (Map #2).

2-historic-veg Map 2 Historical Land Cover

These historic vegetation patterns have been altered by a variety of human uses (current vegetation types are shown in Map #3).

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Map 3 Current Vegetation

Given automation of timber harvest, the timber industry requires fewer people to do the job. There is little in the way of new industry to take up the slack. As a result there is very little pressure to build new homes or expand the small urbanized populations in the upper watershed. Construction continues in the lower Nehalem as second home owners build and remodel homes close to the seashore. However, because of the heavy winter rainfall, pressure for development remains limited.

The past two decades have brought significant actions by a wide range of individuals, organizations, businesses, and agencies focused on better understanding, maintaining, and restoring the health and future potential of the watershed’s lands, waters, and unique human and biotic communities. To reverse the unintentional degradation that came with a century of active, frontier-style logging and farming,  roads have been improved, habitat restored, monitoring programs designed and completed, and fish blocking culverts replaced by fish-friendly bridges. Public policy, planning, and regulations have been developed and implemented on both public and private lands with the goal of balancing the need to both use and responsibly sustain, and in many cases restore, local resources.

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Map 4 Major Land Owners

Though it is appropriate to take pride in all that has been accomplished and give credit to the many who have donated their time and resources to conservation efforts in the watershed, it is also important to ask “are we there yet?”, “is enough being done?”, and “is there need for additional attention and effort?”.    When you review the Health Assessment sections for each of the targets in this document, we think you will agree with our conclusion that in too many ways the health and vitality of this watershed is degraded and/or declining. Examples include monitoring results that show that over one third of the watershed’s river and stream miles fall short of one or more of the legal minimums set by the Clean Water Act, the number of native animal species that are locally extinct, in decline, or at risk, and the increasing economic struggles of the watershed’s residents who support themselves through growing and selling. We are not there yet; we need to do more. Because we believe that there is an important gap between current realities and this planning effort’s vision:

To develop the relationships and stewardship strategies necessary to ensure a future for the Nehalem Watershed that includes ecologically connected, functional and productive landscapes, viable economies, and vibrant human communities”,

we feel that the time has come to build on the watershed’s legacy of cooperation and commitment to honestly take stock of the watershed’s current condition and set a course that provides an appropriate, realistic, and pragmatic route to fulfilling this important vision.


[1] However, the dataset used is known to have a number of misclassified vegetation types, particularly for small-patch vegetation types (personal communication; John Christy OBIC)