The Klamath Hydroelectric Settlement Agreement calls on the secretary of the interior to make a decision on whether to remove four Klamath River dams based on a foundation of scientific findings. That is why more than 100 experts on my team, including biologists, engineers, economists, hydrologists, and others, have been developing and sharing new scientific information for the past two years.

In developing this information, my team used the universal principles of the scientific method to produce 50 new reports: literature review, hypothesis (assumption) testing, data collection and analysis, and publication of peer-reviewed, publicly available reports which are available at Klamath Our team summarized these findings in an overview report that received a second layer of peer review from six independent experts.

We also obtained independent expert critiques of some existing

reports, convened four independent science panels to provide

points-of-view separate from those of federal scientists, and obtained

valuable input during 25 public meetings since 2010.

At these public meetings, people brought forward new information,

topics for investigation, and their scientific assumptions. This was an

open, transparent, and useful public process, and our reports are better

because of it. During our scientific analyses, we investigated many

assumptions, including those raised by the public. Some assumptions

proved to be supported by facts, while other assumptions proved to be

inaccurate or incorrect.

Dr. Paul Houser, in a series of speaking engagements last month in

the Klamath Basin, discussed many scientific assumptions that our

analyses have shown to be inaccurate or incorrect. Although space won't

allow a response to each of these inaccurate assumptions, responding to a

handful of the more important ones is warranted.

Dr. Houser suggested that the federal engineers didn't adequately

study whether Iron Gate Dam would fail during removal. The engineering

analysis of Iron Gate Dam removal was rigorous, the detailed plan fully

describes the process to safely remove this large earth-fill dam with a

clay core, and this plan underwent multiple layers of peer review.

Dr. Houser stated that "the devastation of the lower Klamath from all

that sediment coming out is between one and three feet of the river

channel, 150 feet wide, being covered with silt all the way down to the

ocean." This is incorrect. Sediment-transport modeling shows that dam

removal would release 5.4 million to 8.6 million cubic yards of

reservoir sediment. About 85 percent of this sediment is silt and clay

that would be readily transported to the ocean by winter flows during

reservoir drawdown. Very little of this sediment would remain in the

river channel.

Dr. Houser stated that the "reservoir sediments are quite toxic" and

are "high in phosphorus and probably quite a few other chemicals that

have been banned for years." Findings from our study, and an independent

study in 2006, are contrary to these conclusions. An analysis of over

500 chemicals in 77 sediment cores did not show high concentrations of

toxic chemicals. Chemical concentrations are below "Critical Guidelines"

for sediment disposal and thus these reservoir sediments could be

safely released downstream if dams were removed.

Dr. Houser stated that sediment release "will devastate fisheries for

at least a year or two." Our analysis shows that a winter release of

sediment in a single year, even under a "worst-case" condition (dry

year), would result in less than 10 percent basin-wide mortality of coho

and chinook salmon, and 20 to 30 percent basin-wide mortality of

steelhead. Proposed mitigation measures would decrease this short-term

mortality. In the long term, dam removal would benefit all three fish


Dr. Houser stated "one of the things I do know is salmon were

introduced in the Klamath in about 1895, intentionally, by people,"

suggesting that coho or chinook salmon are non-native. Dr. Houser may

have been referring to a plant of coho salmon in 1895 in the Trinity

River Basin that was overseen by the U.S. Commission on Fish and

Fisheries. This was an effort to replenish over-harvested native Klamath

coho runs with stocks from nearby streams; it was not an introduction

of a nonnative species.

Dr. Houser has never spoken with me regarding these scientific

concerns, or any other scientific concerns regarding the accuracy of our

studies. As senior scientist on this project, I am committed to

bringing accurate, objective, fact-based scientific findings forward for

the secretary's decision.

If my team has erred in an analysis, missed a valuable information

source, or failed to investigate an important assumption or concern, my

science team stands ready, as always, to evaluate new ideas and

information sources, and to correct any errors. This decision is too

important to leave any stone unturned.

Dennis Lynch has been a hydrologist with the U.S. Geological

Survey for 32 years, including studies in the Klamath Basin for 17

years. He is the lead federal scientist overseeing the science and

engineering process for the secretary of the interior on Klamath River

dam removal.