Arizona republican., 1904-08-06
cloHdbursts and the Construction
 of Dams.

The torrential rains in northwestern Arizona whicL have swept away miles CT railroad track and torn steel bridges nnd stone abutments out of the can- yOas as if all this heavy material was dVlGt ood, have attracted the attention Og 4he country to a peculiarity of our dessYt climate. Some of the papers tDmnenting on the disaster have drawn the conclusion that it will be difficult for the government to con- rJFuct storage dams which will cer- tsinly withstand the dynamic force of Q cloudburst. For instance, the San FSa4eisco Chronicle in discussing the late foods in this territory says:
 4 climatic peculiarity of the south eFh part of the arid region of the noun tain states is the socalled 'cloudbursts' which occur with a good deal of reg utaritY in the summer. In these cases atmospheric conditions seem to be such Gs Ia cause the instantaneous conden- AsftOn and precipitation of all the wa ter which the clouds contain instead Uf she gradual change from vapOr to lguld which occurs in most storms. TRae windows of the heavens are open gt and all the water there is comes down at once. When such q condition extends over a considerable area the volumes of water suddenly concentrat- Cd in the canyons at the lowest points uf tae watershed are enormous and they rush down the steep channels Btth irresistible force. No structure hHi6t by human hands can withstand theiT onset, and even when they spread over the plains after debouching from the canyons they do a great deal of damage. Lives are frequently lost hut as a rule t is damage to railroads nhG the interruption of traffic which tInEtitute the principal pecuniary loss.
 The force of these floods and their frequent occurrence may well lead come to fear as to the stability of the .uSFks which tho government may con- Ettlct in that region for impOunding ghe waters for irrigation. It will evil Gshtty be necessary to make them capable of withstanding, not merely steady pressure, but powerful shocks. Doubtless all that is provided for in the estimates of cost, as the certainty of occasional cloudbuTsts is well unde- stood, and engineers would certainly estimate for building to resist them. Ef they do so the reservoirs ought to eRec,ually protect the valleys below them from these destructive floods and washouts. While it might be mpossi- ble to build anything which would withstand their impact when concen- trated in one stream at the lower end of the canyons it would seem probable that they can be stopped and contrOll- ed if taken in detail and before ob- taining the tremendous momentum gathered in their descent toward the plains."
 It is true that the frequency with IyAich imperfectly constructed dams have been washed away has led many people to have misgivings as to tn" Stability of any dams constructed ip ahiz country of cloudbursts. Within the last few weeks destructive floods aud great financial loss have been caused in Colorado and Nevada by Gams giving way. And in this territo- the flood which several years ago de- stroyed the Walnut Grove storage dam and drowned more than sixty people. | But in every case these catastrophes | have been due to faulty construction |
 Competent engineers never have any | difficulty in building a dam that would | withstand the shocks Of the heaviest | floods, if provided with plenty of mon- ey and left unhampered in carrying out | their plans. Thus the greed of the stockholders in the Walnut Grove en- terprise led them to permit the build- ing of a dam which was a menace to | public safety from the moment it was completed. It was not built on the bedrock, and there were no adequate wasteways. The two essential features