Klamath Dams: Sediment studies being formulated
by David Smith, Siskiyou Daily News 7/15/09
Siskiyou County, Calif. - The sediment behind dams along the
Klamath River should soon be tested to answer questions from all
sides of the issue on whether or not the dams will be taken out as
part of an agreement in principle reached by dam owner PacifiCorp
and a number of stakeholders and stakeholder groups, according to
Dave Gore, project manager for the Klamath with the Bureau of
Gore said in an interview Tuesday that the sediment studies are
still in the formative phase, during which he will work with
PacifiCorp, the Environmental Protection Agency (EPA) and others
to develop a framework, which will determine the substances that
will be tested for and the areas that will be tested, along with
Although the studies are not yet finalized, Gore described general
protocols for sediment studies. He said that the sampling
essentially involves taking a barge over the area being tested and
“core”?samples are taken from the sediment. He added that the
substance being tested for will dictate how it must be handled;
for example, some samples may have to be frozen on site with dry
ice before being sent to the lab.
Asked what the number and distribution of samples would be, Gore
said that he and his agency will be working with the EPA?and its
Corps of Engineers to determine those aspects of the study, but
those have not yet been determined.
“We’ll be trying to distribute the sampling so it is
representative of where the sediment is,”?Gore said, explaining
that while the sampling can show the spatial locations of toxins
if they exist, it will not be possible to determine everywhere the
toxins may be.
Gore stated that even though the testing can not give a complete
picture of where the toxins may be, it can reveal what possible
problems exist if the sediment is released. He also said that
determining where the toxins are also depends on the type of
toxin, as some may latch on to sediment particles, while others
Asked how accurate the sampling is for showing whether or not
toxins are present, Gore said that that number typically depends
on the type of toxin tested for because different tests have
differing levels of accuracy.
Gore said that toxins will not be the only aim of the study, which
will also include an approximation of the volume of sediment
behind the dams.
According to Gore, the group will be using bathymetry, the
measurement of the depth of large bodies of water, in its attempt
to calculate the volume. He explained that in order to get a more
accurate estimate, an attempt must be made to differentiate the
accumulated sediment from the alluvial material that makes up the
original lake bed.
Gore said that once the sediment level and the alluvial level have
been determined, a computer model can be used to calculate the
volume, and he said that he would like to make three-dimensional
models for a visual image of what the sediment buildup might
actually look like.
Ultimately, Gore said, the studies are to determine what will
happen to the river during dam removal. As the studies become more
clearly defined, the Siskiyou Daily News will cover the aspects
that have yet to be determined.