Show i vr rr The New Croton Dam One of the Wonders of the World larger than Three Greatest European Dams Combined The Great Croton Lake Masonry Dams ol Comparatively Recent Origin I x 9 completed which Is to F1hS 34000000000000 dam just gallons of water 1 d citys water supply Is I hew Yorks the world Wo dam In largest thelAssunm I e ce hoard n great deal of tho Assimm I In Egypt built to control the V m Roads of the Nile but the ling t is more of a olke than nand suam and though longer than the Cro dam Its height Is but 70 feet toe n 301 feet of the other e dam England has the notable Vryny Knee tho FureiiB Belgium tho Gllep I ante the three great dams of Europe II now Croton dam is larger than e UV combined ese three it ee t has taken 14 years to construct and cost 7700000 In the Is work construction there has been a wr of of lIfo compared eally email loss comar ° undertakings of this kind th other me men were killed by premature few other and there were a nloslons 44I clients but Mr Coleman the chief the firm of contractors which built e dam says there has been less 5S of lICe In the work on the Croton m than on any other similar work the history of such operations ce the work was retarded a short i me by a strike and for three weeks Seventh regiment was kept busy it the dam but no other serious dls rbance Interfered r Work was begun In tho autumn of to a 92 and on March 10 of tho present u ar the workmen laid down their ill iols the dam was finished A trip eta er the construction railroad was co ade by Mr Coleman tho engineers t a the work and the Catholic priest I ore ho had had charge of the two chaps UIJ chap-s built for the workmen then tho ° sl ails were torn up and all signs of tho ay ofk of construction removed as 16lbi ulckly as possible > 1 lbiKl The great stretch of land below theM the-M ew dam belongs to the city and this tart as been graded and will be made Into f f m d ne as t HtMaimWIc park When the city obtain v151 N possession of the tract covered by iSt Wta tBr6 dam and lalte > many roads and r r cal bridges had to be done away with sea These have been replaced by the con pal krudlon of 3G miles of macadamized Its d road along the shores of the lake Where the Croton was once but a ONDr narrow river Its character has been so changed It becomes a great lake MOO feet across at the dam breast filling the valley behind It for nearly 20 miles and spreading at Hunters Brook to an extreme width of two miles Three miles from the new dam U the old Croton dam onco regarded as a wonderful structure when tho waters have risen to tho top of the new dam the top of the old Croton dam will be oi feet below the surface sur-face The new dam Is divided Into three t sections The main dam extends 1 400 feel from the south side of Croton valley to a point where spillway andy 1 and-y bridge span begin Tho spillway which curves away to the eastward Is 1000 feet In length A steel arch Midge 200 feet long follows the straight line of the main dam and over this and tho top of the main dam J Is a highway 21 feet wlae After the v eater passes the spillway It lows unto un-to the bridge Water that has risen to the top of tho spillway will bo 1G feel below the level of tho highway The J depth of water In the dann will be ICO feet a When New York nndol took tho con Action of a now dam considerable time was spent In the vitally Import tat t matter of selection of n site At Grsl a site a mllo and an eighth farther down stream was chosen but no con Strucllon was ever begun at this poInt Boriuga were made all over the valley before nnni decision was mado and fork I began It was found necessary KBOt > to renetrate to the solid rock for a 1nsclou Item WWatlon and not until a depth of 8a ure t the m trm el Was so 111 d 1 rock reached On this hlddPI most foundation has been roared the Is suit lbost enormous 1Icco of masonry in iake tW the world i enQ Is 2100 fcct long from nl I VU north SOUth eml of tnc main dam to tll ° g Wm It rtb end ot the spillway At Its base 216 Ie raID tad feet thick and this tapers to TW ac the top where it is ten feet scrim rh ross at the top of tho main dam luliiyBfcul116 of the Inner wall Is very In co itll1L That tho reader may have IS agd atVPPreclnUon of the size of tho ad 0 ° I teiri III Wc reproduce well BumpS t ntlmtenneprwell pS trlr tu ormiitlon conrornlnu the rudPI endous Imrlaeciing feat The table appeared In the Now York World NEW 7700000 CIIOTON DAM AND ITS SK Cost 17700000 Tlmo ofcoiiHtruitlnnyvnrs 14 Adds to citys water supply gallons 31Oi OWUAlW Total length feet iWC IeiiKtli of main dam feet MW Length ot Kplllwuy nver which water will low feet 1iW 1 < > Length of bridge span over outlet for water below spill wny feet 1W eight of bass of foundation to main than top feet 218 height of main darn top above spillway top leet 16 Depth of water behind dam when mowing over spillway feet ICU Depth of water now In thou feet 95 Thickness of masonry at bane feet i10 Thickness at top of main dam feet 21 Thickness at spillway top feet 10 Length of lake formed by dam miles 19 23 Extreme width of lake Hunters brook miles 2 It Is comparatively recently masonry mason-ry dams of notable size have been constructed con-structed they are a feature of the development de-velopment of modern engineering In the sixteenth century there were In existence masonry dams of great height but only In the last half of the nineteenth century were they designed design-ed In accordance with the great prin ciples of engineering maximum strength with minimum of material anti cost In masonry dams the danger to be guarded against Is crushing I There Is the pressure of tho height of water behind the dam to be met by sufficient resistance and the crashing of Ice when the spring floods come In the new Croton dam which Is the climax cli-max of masonry dams the most famous fa-mous engineers have handled these problems While the steps of stone below tho spillway top are rough and uneven the work there Is If anything more carefully done than In the main ar pal coati gala 1F I t f1 Iso I l so a ti l + Name u nple t 1 0 f r 0 J to or y t W j 6 y s erect t 1N1 JJ o z that i3t 1 i 7hED l I f 1 s 1 adgu asl0 l0 rrth rengt CLIMAX IN DAM BUILDING dam The rough steps ate made of great blocks of stone from two to five tons In weight and they are Joined with the finest precision When the floods of early spring bring a great volume of water over the dam It will be full of Ice giant blocks many tons in weight which must be crushed as they drop from step to step below To meet their shock and to reduce them to powder the big stone blocks were put in the face of tne spillway The layman Is perhaps better able I to appreciate in some small degree tho sklll required the rare necessary in I construction or such a work as the Croton dam by glancing at great I works built elsewhere that have I j proved In some vital point weak In adequate In looking over the subject I of dam building and the great dams of the world the writer comes upon the chronicle of what Is spoken of as dam failures learns that the common com-mon causes of failure are sliding on joint the base or on some horizontal overturning fracture due to tension crushing In the case of masonry 1 dams and rarely I the breaking up I I down I the top and washing away from ward Time most disastrous reservoir failure of recent days was that generally gen-erally alluded to as the Johnstown flood when 2000 people lost their lives and between fliUOOOOO and 4 000000 worth of property was destroyed destroy-ed The South Fork dam an earth dam built about three miles above was carried away and the Johnstown reservoir emptied Itself In about 45 minutes The failure here was an Insufficient In-sufficient wasteway Tho original specllkatlons for the dam called for a waterway JnO feet wide at the time of feet the disaster the way was but 130 In width Walnut Grove dam In 1SOO the Arizona In one of the highest rock fill ever built failed and many dams thereby An Inadequate were lost lives thought to hav spillway Is quate 811 qua disaster The Walnut this caused 110 fret in height dam was Grove 14C about ten feet thick at tho top Granite blocks com tho base feet at wall both faces the dryface walliii posed 20 foot thick vret tho heavy base rainfall and five anti at er A very the top worked the spillway Inadequate tho foundation and aver Defective ruin lasting several I days rainfall heavy of the dam on thi the failure caused Austin Trxa < Colorado river at I which occurred II > pill 1900 |