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Richard E. Goodman
13110 Pomo Lane
Mendocino, CA 95460
E-mail: REG@mcn.org
Phone/fax: 707-937-1018

To whom may concern:

Comments on Feasibility Report Chalillo Dam Project, Belize

1.  At request Mr. Tony Garel Belize Alliance of Conservation NGOs (BACONGO) Mr. Ari Hershowitz the Natural Resources Defense Council I reviewed documents concerning planning design Challilo Dam on the Macal River Belize. I received sections final feasibility report AMEC E&C Services Ltd dated Sept 2002, covering Geology Geotechnics. I received copy of review comments Mr. Brian Holland, Tech Director of Belize Minerals, Ltd.

2.  I read technical material provided AMEC first and made notes. Upon reading comments Mr. Holland, I found many points I had annotated important were featured Holland's review well.

a)  First foremost these assertion the foundation rock includes much interbedded sedimentary rock and granite. highly improbable because granite is an intrusive rock formed many kilometers depth within the crust, whereas sedimentary rocks represent products of accumulation cementation sediments surface of the earth. Unless entire foundation were composed of some sort melange zone, complexly splayed thrust sheet, product "l par lit" intrusion, mistake has been made identification rock types. The more reasonable explanation report error. A close inspection rock with hand lense or microscope would clearly distinguish feldspathic sandstone or arkose granite because former clastic in texture whereas latter crystalline. Apparently Mr. Holland has examined rock judged supposed granite site reality an arkosic sandstone.

b)  Another point inadequacy report its professed ignorance with respect possibility of leakage through karstic limestone around reservoir rim. The cavalier statements report with respect this eventuality are not supported documentation any kind. Furthermore, lack confidence with respect to knowledge site stratigraphy engendered reading this report allows uneasy feeling possibility for soluble limestone occurring within volume rock forming foundation abutments can not yet be dismissed.

3.  These criticisms site geologic description are not picky – suggest fundamental flaw most significant aspects site investigation. The geological makeup dam site affects adequacy and acceptability any specific design scheme. Without accurate geological information site geotechnical model can not developed resulting design will probably be seriously wrong large small.

4.  The development satisfactory site geotechnical model involves not only description type rock forming all parts foundation, abutments, but the structure these rocks great detail. At design stage, should possible predict potential sliding surfaces within foundation zones of potential leakage and/or internal erosion. These details are life death information construction gravity dam on sedimentary strata, especially where sandstones and shales are involved. Without such data, not possible to know ahead actual construction what final project will look like, if will succeed fulfilling its intended purpose. can expected will be significant cost overruns, safety project can not assured advance. With respect safety of the project, dam must not endanger public or property wildlife ecology downstream. Since the feasibility report does not include graphs data exhibiting specific structural information about rocks, and since gives little geologic interpretation sufficient allow creation geotechnical model for the site, report must judged incomplete.

5.  On basis samples feasibility report that I have reviewed, I judge report both inaccurate incomplete. means designers lack information on which provide an assuredly satisfactory safe structure. Therefore can not be stated project feasible can not be established project safe. No civil engineer or public authority can ethically venture design call for the construction work whose risk can not assessed. This especially true hydraulic impoundments, which have capacity inflict great damage life, property, and environment.

Sincerely,
Richard E. Goodman