1867 Bathymetry points from US Coast Survey Office (Army
Corps of Engineer) A Xerox of this historical map (US
20,000, Tillamook Bay OR: Ben Pierce)
was obtained from the Army Corps of Engineers which was
photographically reproduced onto mylar and digitized.
Several studies of sedimentation and sediment composition
have been conducted in Tillamook Bay (e.g., Avolio 1973,
Glenn 1978, Komar 1997). The latter report provides an
overview of what is known about sedimentation of the bay,
which is an important environmental concern because of
its influence on habitat quality and navigation. Bathymetric
surveys were conducted in 1867, 1957, and 1994/1995.
E&S performed a comparative analysis for TBNEP of the
available historical bathymetric data sets for the bay. The
objective of this analysis was to quantify, to the extent
possible, the changes in bathymetry that occurred between
the times of the available surveys. It is considered likely
that the bay has received excessive contributions of
sediment since the last century. Major sources include:
1.the breach of Bayocean Spit between 1952 and 1956
2 deforestation in the watershed
3 Tillamook Burns of 1933, 1939, 1945, and 1951
4l and use practices in the watershed, including road
construction, agriculture, and urbanization