Page:Popular Science Monthly Volume 74.djvu/445

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TBE TYPE >T TEE PAS AM A CASAL ^:

dq)06ife. so that it can no -displaee the eartii particles wiiii whidi it comes in contact in its i-assge nnder tihe dam. To make a con-riDciiig estimate of the vohnne of nw in the porons snb-smface strata imder the dam is almost out of le question, hecanse ihe eitait, chancer and continnitT of these rtita can not he defimtdr ascertained, and it win he diflBcnlt. if no: impGesibley to determine at what point or points the water will mk fr?™ t^e lake aboTc iiie dam into these layers. The en^lners ~ Therefore, do no better tiiam make nnfavorahle assnnino:!^ __i determine "Hie maximum water loss that may resiil: nder inch hypotheses. There is no proba- bflitr that this will be sncl as to prove anbarrassing to the project It is to be remembered in tis connection that nearly always, wiien a subsurface flow in a river chnnel has beeai developed by the etmstme- tion of a subsurface curtain c dam. the result in water output has beoi disappointing. In other weds, the probability is t " ' --£ —

will be over-estimated- Xevrtheless, the public seems ;o ^xz-ev: r- " : assurance that ti»e canal wc£ is progressing a] . - - -r-

ticularly as it now appears pDl>able that the cor: ~ "

be more than double the amont named by the ..— - . __ . ::i m comparing the cost of the tw types of canal.

In the writers opinion. : may confidently be assrir. :*e

dam can be constructed at btun. The situation at '. fore, of minor importance in be further discussion of the has again arisen: "Would i -ot still be wdl to change : project and to complete the icavation to sea-level ? This q^iestion, if it be again opened, will hve to be considered in the light of the views of the experts whose opiions have been herein referred to. ' light of the work already doc and the progress already made : :i light of the experience on the qthmns during nearly five y?^~- - * ' :- ive work, and in the light oi-uch additional facts and e::------- -

mav be submitted by the ensieers now about to rrarr for the is-_ r

Jantiarv 25, 1909.

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