The earliest aerial photographs of Humboldt Bay entrance that were found to
exist are a set of four 1934 aerial photographs, copies of which reside at the DPW
database. This database is one of the most comprehensive in Humboldt County
and also on a regional basis. A 1938 aerial photo flight, that probably includes
the entrance, is housed at the San Francisco District. Six of the 1939 aerial
photographs are at DPW, and more may exist at the San Francisco District or in
the Federal Archives in San Bruno, CA. The earliest most complete aerial
coverage for the entire bay is the 1948 California Division of Forestry flight.
Aerial photograph coverage for Humboldt Bay became more regular starting
with the 1953 aerial photo flight. These aerials along with the 1954, 1958, 1962,
1965, 1966, 1969, 1970, 1974, and 1981 aerials, now held by DPW in the
database, are mostly the historic holdings of the Humboldt County Assessors
Office. The county was flown regularly for property assessment purposes up
until the passage of Proposition 13 (a statewide property tax initiative) which
changed the basis for property assessment to a calculation based on the purchase
price of property with annual adjustments limited to a percentage maximum of
2 percent, instead of use of field or aerial photo surveys for property evaluations
and property tax land assessments. The lack of funding has made it difficult for
the DPW database to obtain more recent aerial coverage of Humboldt Bay,
except for smaller scale project site aerials.
Humboldt Bay was flown regularly from 1977 to 1996 by the San Francisco
District, with copies of the aerials now held at the District's Eureka Field Office.
Aerials flights occurred in 1977, 1978, 1979, 1980, 1981, 1985, 1988, 1994, and
1996. The 1985 aerial coverage was taken in color-infrared (CO-IR). The San
Francisco District's Regulatory Branch has contracted for an annual CO-IR high
altitude aerial photograph sequence to be flown for the entire Pacific Ocean
coastline for which the District has responsibility, from San Luis Obispo County
north to the Oregon border. The flight is typically taken in October of each year.
The aerial photographs are taken for enforcement of regulation (Section 404-
Clean Water Act or, Section 10-Rivers and Harbor Act) purpose.
The DPW database slide collection has some examples of these photographs,
from the late 1970s early 1980s, primarily limited to Humboldt Bay Entrance
Channel and Entrance Bay. The images are striking and often clearly show the
slides were not separately listed in this report, and the slide collection is referred
to as a single entry in the Appendix A table. The individual slides were made by
occasional DPW staff visits to the San Francisco District by making
arrangements with Mr. Douglas Pirie, former coastal engineer for the San
Francisco District. Color slides were made by mounting the CO-IR aerial photo
negative rolls on a dual roller light stand and setting up a camera on a tripod to
shoot the desired aerials as the negatives were passed over the light box. Once in
slide form the scale of the original aerial is compromised, but slide scale can be
estimated and prints can be also be made. As the negatives are on rolls, it is
difficult to easily obtain the aerial photographs of choice as it takes time to find
the desired negative in the roll.
There are three recent aerial photo flights of Humboldt Bay, one color flight
in 1997, and two in 2000 (1-color (CO) and 1-black and white (BW)). The two
color flights (1997 and 2000) were flown under contract from the CDFG,
Northern California, North Coast Region Information Services Branch to
Chapter 4 Inventory of Available Data and Data Sources