dams on the Klamath River blocked fish for millennia
by William E Simpson III
Numerous published geologic studies
and present-day observations show that over the course of
past millennia, a series of no less than five lava flows
crossed the Klamath River.
At least two of these lava flows
dammed the Klamath River at Wards Canyon.
These lava flows, which dammed the
Klamath River, are also called "reefs" or "dikes" by
geologists. These lava flows formed tall dams that without
doubt blocked fish migration for millennia. (See Fig. 1)
One of those five dams was 130 feet
tall off the riverbed and was 1,000 feet thick! (See Fig. 2)
The slot that was eroded-through the
1,000-foot thick, massive 130-tall lava dam is seen in image
Fig. 2. The modern dam, Copco 1, was built in the downriver
end of the slot, and can also be seen in the drone photo
This 130-tall natural lava dam on the
Klamath River formed a large lake called Clammittee Lake
that was five miles long and one mile wide.
Over the course of thousands of years,
the Klamath River finally cut a narrow notch down through
this massive natural lava dam. And as the water level in
Clammittee Lake fell, the Klamath River eventually ended up
being held back by a smaller 31-foot-tall lava dam a
quarter-mile upriver, which maintained a smaller version of
Clammittee Lake through 1911 and the completion of Copco 1
In 1911, when the famous engineer and
dam-builder J.C. Boyle arrived at Wards Canyon to build
Copco 1 dam, he noted the existence of the 31-foot-tall
natural lava dam that held back Clammittee Lake.
J.C. Boyle made a detailed drawing of
that 31-foot-tall lava dam and its lake (Clammittee Lake).
That drawing was published in 1913 and that image is
associated to this article for reference in Fig. 3. Figure 3
shows the flow of the Klamath River over the top of that
natural lava dam, the riverbed and the location of Copco 1
dam a quarter-mile downriver.
J.C. Boyle took advantage of the slot
cut through the 30-foot-tall lava dam that was a
quarter-mile downriver from the smaller 31-foot-tall lava
At farthest downriver end of that
slot, J.C. Boyle integrated his new dam (Copco 1) into the
solid rock that was part of Nature's massive lava dam.
The resulting modern dam was nearly as
tall as the original natural 130-foot-tall dam, and brought
the water level in Clammittee Lake back up to where it had
been thousands of years before, restoring that ancient lake
to its full glory where a myriad of unique species of flora
and fauna had evolved and remain present today.
Today, Clammittee Lake is within the
present footprint of Copco Lake, which is situated behind
Copco 1 Dam. Copco lake alone holds 25 billion gallons of
The foregoing evidence belies the
premise argued by dam removal proponents that fish from the
lower Klamath River basin had allegedly migrated past Wards
Rock solid evidence, geology, proves
that is a false premise.
William E. Simpson II is a naturalist studying the wildlife in
the area around the Klamath dams. He is the author of two
published books and more than 100 published articles on subjects
related to wild horses, wildlife, wildfire and public land
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