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"Further Comments to Bureau of Reclamation" from Clay-Core Engineer Stephen Koshy
    regarding "catastrophic collapse" of Klamath River Dams if they are destroyed

To KBC News 4/17/18

Please read this along with my 2 letters to the Bureau of Reclamation (BOR), a letter each to the County Board of Supervisors and the County Counsel, and the BOR reply to my comments as reference.

Bureau of Reclamation (BOR) in response to my comments, through their technical memorandum, says that they are giving ‘detailed responses to my each comment’. Unfortunately, they are not.

The BOR sent me a printed version of the EIS/EIR in Oct 2011. I thank them for that. I do not have it with me now . Their online electronic version seems to have some changes from the printed version that I had quoted  from.

My original comments: In my letter dated Dec. 21, 2011, I quoted from the printed version Chapter 3, para  3.11.3. 5, which had mentioned potential landslides: …. <Quote>  relatively steep slopes, underlain by tuff ….. wave action at  the shoreline of the reservoir has eroded sand and volcanoclastic tuff beneath diatomite beds and has resulted in the calving of diatomite into reservoir creating vertical exposures as high as 20 ft. in the diatomite.”…….”the (fine grained) red volcanoclastic material underlying the hill slopes ……. may be vulnerable to rapid erosion, if subjected to concentrated water flows.” Also that ….

Chapter 3. Figure 3.11-2 identifies existing potential landslide areas in the iron gate and Copco 1

Reservoir areas.    EIS/ EIR has enough information to suggest the certainty of slope failures on draw down, but failed to investigate them. The slope failures will add to the sediment release.  <end of quote>

The BOR, in reply to my comment, informs that they did not conduct detailed slope stability analysis because there are no important structures atop the slopes, but my concern is the sediment release, which the BOR do not address. The BOR states in  reply that they will consider detailed stability analysis during dam removal. My further comment to BOR is that it will be too late by then.  I have concern also that possible instability of abutments during 174 ft. draw down will be catastrophic to the iron gate dam.

As another comment in letter dated Nov 18, 2011 to BOR (Mr. Thomas Hepler), I said that “these dams have clay in the middle, saturated in water for decades” …… My comment on Dec 21, 2011 to Mr. Thomas Hepler said that … “The dam’s clay core is saturated in water …… The dam’s instrumentation would reveal the pore pressure at different elevations.”

In reply, the BOR says that …….. “it is Reclamation’s understanding that they are primarily composed of silt and sandy silt”. They are wrong. The BOR document “ Detailed plan for Dam Removal, Klamath River dams, US Department of the Interior, Bureau of Reclamation Sept. 2011” on page 19 says:

<Quote> ”The embankment includes a central impervious clay core with filter zones and a downstream drain and is flanked by compacted pervious shells” <end of quote>

My further comments: According to BOR’s own document, the core is of impervious clay .The central impervious clay core is predominantly of clay and validates my contention. The core is made from the “fine grained red volcanoclastic material underlying the hill slopes”. BOR should please re-examine the borrow areas from where the material for the core was taken and processed. It is true, it would have  some silt, even some fine grained sand. But the predominance of clay gives it the properties of clay. The question is what % is clay, what % is silt and what % is fine sand.  The BOR ought to respond.

To me, the sediment behind the iron gate dam gives a clue . After all,  it is made from erosion of  similar volcanoclastic  material that has been placed  in the core of the dam. As reported by the online version of the EIS/EIR, the sediment in the lower section of the reservoir consists of 60.7% clay 25.5% silt,  2.4% sand and 0.4% gravel.  Mind you, the gravel and sand were already there before the construction of the dam. A lot of the clay particles, being in the top layers of the reservoir, have gone out of the reservoir with the overflow during the past 56 years.  The % of clay in the core could be even higher than these.

For the lay man’s  information, silt is less than 74 microns or  0.074 mm  in size, passing the ASTM 200 sieve. Clay is classified arbitrarily as less than 2microns or 0.002 mm in size  What passes  through the 200 sieve or 74 micros size contain also 2 microns size which is clay. In this instance it is predominantly clay so that BOR  terms the core as impervious clay core. Sand is classified as more than 74 microns in size.

To say that it is BOR’s understanding is a vague language. Engineers look at facts and evidence and not here  say. The BOR ought to examine the dam’s permanent records since every dam’s specifications and test results of samples are kept as permanent records.

Another issue that I raised and again repeat now is that taking down the earth dam by heavy earth moving machinery is not just doable. The Core of the dam after soaking under reservoir water for decades is extremely slushy and cannot support the heavy weight of the machinery. Even lay men without Civil engineering degrees can understand that. Yet the BOR seems to think that it can be done. I would argue that it can not be done.

Above issues are important. However, the most important issue that I raise is that the clay in the core is saturated with water and its water content is over its plastic limit, if not its liquid limit. The BOR or for that matter any civil engineer would agree that the  outer gravel shell exerts lateral pressure on the clay core. This lateral pressure is huge and can be calculated. It depends on the internal friction and cohesion of the gravel shell and approximates to 0.7 of the vertical pressure at each level.  When the deconstruction of the earth dam reaches the level of the saturated clay, the clay will yield to the lateral pressure of the gravel shell and the dam will collapse.  It would be catastrophic. It is due to the voids in the clay core being filled by reservoir water under pressure for decades and the water content in the clay exceeding the plastic limit (or even the liquid limit closer to the core contact face with the reservoir).  At progressive depths, there is progressive water pressure.


Conclusion. My analysis is purely technical. I do not have any political  affiliation. Nor am I a stakeholder. I attempt this for the sake of God and Country, for the Glory of God and duty to the Country. I accept my limitation. I am not in the engineering field for over 3 decades. My training by the United nations on Stability of Slopes and Earth dam Design at the University of Queensland, Brisbane, Australia, was over 45 years ago. I wish I could write more. I am aged 83 and suffered a stroke. It affected my capability for effective writing and for arranging ideas in logical order. My poor health after the stroke is preventing me from writing more. Consequently, I have left out many further comments. I do not have Manuals or other literature with me.

I anguish over the unfortunate Salmon. If Salmon would be helped by trying to deconstruct the dams,  I would be happy. But that is not the case. As I said in earlier letters, its effect to the Salmon would be adversarial. Seven years ago, I offered to help with an engineering solution, but BOR would not accept. After all it is their turf and I understand. But I have concern about the error in the EIS/EIR. My request is that the County Board of Supervisors, the County Counsel (who have my several letters) and others such as the Honorable Members of Congress on both sides of the border who have the resources, refer my submission/analysis to peer review by authorities on the subject, who are without conflict of interest.

Yours Sincerely,

Stephen Koshy


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