2 Description of Study Area
Humboldt Bay is located on a comparatively isolated part of the northern
coastline of California. Although, as presented in this report, a good deal of
information exists concerning the bay, it is relatively poorly studied compared to
other estuarine and lagoonal features on the U.S. coastline that are of similar
scale and commercial significance. The descriptions in the following paragraphs
are provided as a framework within which to assess and access the database
provided in Chapter 3 and are not intended to be a comprehensive summary or
investigation of the physical oceanography of Humboldt Bay.
Humboldt Bay is a multibasin, bar-built, coastal lagoon located
approximately 260 miles north of San Francisco, CA, and 220 miles south of
Coos Bay, OR. The watershed of the bay is approximately 223 square miles.
The major rivers in the region do not drain into the bay, and point source inflows
of fresh water are small. The annual freshwater input to the bay is on the order of
the tidal prism. Therefore, estuarine conditions are found in localized small river
and creek mouth or slough areas and typically only occur seasonally. These
peripheral sloughs are best described as seasonally transient estuaries within the
overall lagoon. Therefore, the circulation within the bay is almost entirely tidally
dominated, and the hydrography of the bay is normally unstratified marine water.
The north coast of California at Humboldt Bay is a cool and moderate
climate with few extremes. The climate is marine dominated in response to the
cool southward flowing California current system. The air temperatures seldom
exceed 75F and only infrequently drop to the freezing level. Rainfall is
moderate, with normal rainfall around Humboldt Bay ranging from 30 to
40 in./year, occurring mostly in the November through March wet season.
Summers, however, are often foggy until mid-August, with morning fog
sometimes dissipating in the afternoons. Ocean temperatures are in the 50 to
60F range and typically are between 52 and 56F and do not vary substantially
throughout the year. Hurricanes and extratropical storms of similar intensity do
not occur in the region.
The wave climate, however, is the one extreme condition that Humboldt Bay
experiences on the north coast. The Pacific Northwest region, Washington,
Oregon, and the north coast of California, experiences the most severe wave
climate in the continental United States. Swell from both the South Pacific and
the North Pacific reach the coastline. However, swell from the northwest
Chapter 2 Description of Study Area