| Show 1 1 Ae t o t e Big Bi Cotton 1 Conduit Cond it Will W ill Bring W ter to o l lr r Plans Contemplate Construction n of Concrete Channel Rectangular in Form Built to Allow for Total Plow Flow of Almost st 40 Gallons G Per Day to Reach City at Sufficient Elevation to Permit ermit Future Extensions Extensions BY GEORG M BACON ENGINEER IN CHARGE T Mouth of Big Bug Cottonwood Canyon Showing Point Poin of Diversion r Looking Northwest from Mouth of Big Cottonwood Canyon J ir t t A a T t lF Y Ras a lt 7 t gc i I 3 g tt wt 5 s n w 1 4 j IF r t ts s Y sy t 4 l Y i a a Zt sY M 8 4 v t i t x A t r a 4 lt R 3 a aay ay j jf jy i n f S y r y va vat t t tS i ia itai a d tai w v sn k Y J i Y W t ft a r t 4 t r ra n re e a e erM r rM 0 f fre f ag age e a Ir Iri Ira a h V v i f a f d fr ft fl a r l 1 0 t 1 Rr M W Wr V r x xu u 4 y k 3 y f xa F a ai i x d a V aw a Y f T 3 3 A d o P V k kt t cI i V x xv xvi g i a S r rI S t I VVS x rh Looking West Down Mill Creek Looking Up Parleys Canyon at City Reservoir The Big I form the luain channel which will trill bring the wa tva a atIS tr rt of the additional water supply into tit alt Lake City It extends from Big Bigut ut ton wood creek to Parleys creek a It of ot a rattle little less than eight eightMile Mile The conduit will ill for tor the wes pres tnt ent nt bring tics the waters ate of Big Die Cotton Cottonwood Cottonwood wood which the city elty has baa now acquired to Parleys Parley canyon and the Parleys canyon anyon conduit t will bring them into the Thirteenth Ea East t street reservoir re The water waters at n of oJ Little Cottonwood CoU creek nill t ill later b brought to Big Bi Cotton v iH nod d by a supplementary line and from front T Rig Big iK Cot Cottonwood ton woud by the conduit After f the he h as aa grown crown so 80 that the capacity t It f Parleys conduit la Is i too small to toh bring Jl h ing ug in the necessary water an ex extension tension nuion tt of the Big Cottonwood conduit Mil ill have bave to be made onto the bench beach Cast tast t of the city The TIle Big Bt Cottonwood conduit was de designed designed signed to carry the total low water flow of Little Cottonwood Big BI Cotton Cottonwood Cottonwood Cottonwood wood and Mill Mm creeks The rhe best data d callable shows show that this thin th combined low water flow will at some time be in the neighborhood of ot gallons gallon per J day While hUe the low water flow at present pre press tt does not reach this t figure U it teemed seemed eeme 1 wise to bear hear Inn nand that in future years reservoirs res conserving the lood 1000 waters to some seine extent could d be guilt Tills This matter was tare gone into care carefully tatt JIe rt fully Tally and a fair allowance all for Cur H lure ture t ure possibility was as figured ed on At Mill creek provision on is 18 made for tor taking a 11 i what waters the city may hereafter r rit squire Acquire it horn from this source Planned for fair f Greater System The Big Cottonwood conduit starts taru i iti 4 t near aa as DO to the taU tall race of fr the Utah Light Licht Railway l power ower house at the mouth of Big nil Cottonwood Cot f wood canyon This will m enable the lh extension from Parleys creek that ome some day must be built to cover a II region at the east of ot the city nearly oo 00 feet above the Thirteenth East res rett reservoir reservoir It has baa been objected to this th upper UDDer line that it is much more ex tX expensive x pensive than some of ot the alternative ones onea but this th objection is 18 hardly war warranted warranted warranted ranted by fact tact and it is a matter maUer of judgment how much value attaches to having the line as high hleb as possible The history of all canals and similar rater ater n feeders in this arid region is that they were not built high enough At time of ot construction they seemed sat factory but sooner soother or later it be omes omo evident that it would have been beenA A ise t in Ute U e beginning to have placed them hem as q s high lilek as u possible This consid ration not hot be minimised by 1 hose wits wl wI a think that some money thoney avin pt Ott have lave been made by a low lowe lowr e r I line Composition of Conduit The conduit Itself consists essentially if tf f a concrete flume or covered channel h I t is practically e rectangular in cross v tf b feeing 8 E 12 feet wide Ide by 4 meet 14 It et tt ma rl When ben the conduit is 1 filled i 1 lit Us its ultimate capacity there will still stilli i t lit an art air space pace the water of inches which h will aid the ventilation t and nd ke ket keen M JI ih the water sweet About hour every try 1808 1000 fret f tt th there r will be a with a Ii lI cover cove which situ atho tidy aids in aerating ae tin tilt water Over Oer Overe 0 10 e per WI i c nt ut t of or the th line is iri In x The various V l U maces laces where it would have hate lIa t tort cost ton inn much to tl follow into the lie mull 01 gullies f t tin til sake sak of or keep n I Hn the r conduit in ill were heeled t l in III a d sj s e iU idl n 11 to equal qua s i of oust ui 1 It was l unwise t tj all ill l a t run ure If of nr this th Is K i ir i 1 ft I t I i ret st U l made grown group therefore thereto where the con conduit conduit duit is k i not in excavation it is sup supports suppo ports p po i In ltd h tO Ule a piers fifteen feet ip t H t aid ald they then tt iou of the conduit ie is iA t that Hiatt none of its 15 weight w eig tt is carried ank by b the earth filling The Tho bottom amid walls of the conduit are aro arosix six inches thick and the roof varies from front four Cour to six inches as th the amount of filling on top of it demands The Ther root roof r of is ds in all cases ca reinforced by steel rods reds r ds Imbedded in the tho concrete and the pressure e against the th sides warrants warrant It this thia type of reinforcement is I also al o used 1 Reasons for Rectangular Form It n may be of or interest to state here hems some ome of the reasons ons which h led to the tha th adoption of this clO for a 8 a conduit in the place of the used for tor Parleys creek conduit This latter was as essentially e circular r with a square base and was also built of conr con concrete concrete crete Under conditions of uniform external or Ot internal pressure pres ure the Circular in is the ideal one olle for b beet t resulting these pressures wes Ufe In the th ca c case e of ot the Big BI rot t ton wOOl conduit the Une line has a tl uniform slope e from tom start to finish and the pressure Jre ure on the inside will only Oly be lie b at atthe atthe atthe the bottom end nd skies sides and does not re remotely remotely remotely approximate a teen internal pressure pre sure The external pressures y vary ry with the different pa aged I through and antI the depths d th of excavation Moreover Mo reaver on Q 10 per p er cent cant of th line we have the conduit any covering cO I at stall all It will be ore that the prime Battens for foe adopting a ft e cular n there weigh very strong ly I the construction difficulties The n ncr man knows that it costs coats mote more mo eto to hi kt I 1 concrete In a a 3 C thau tHI till ajl things thing being b i equal there is I the lia 1111 liability liability of having nc a poorer job in hl the first firK case cae The rectangular section lends itself most readily to the idea id of or supporting it on mr piers where the ground under underneath et n neath ath could not be depended on As Aa designed ned the conduit has exactly the e spore same internal i e c ion n throughout its Us entire length ant and yet ja for the varying conditions ns to which it must be subjected in excavation tun tunnel tunnel tunnel nel and on embankment The conduit pass Ia through ei el JiO t tunnels one of which Is hi In solid rock r k kaDd and aDd in these tunnels th tot section is JOd flied by the substitution ofa of 01 a brick arch for tor the usual u ual concrete con roof slab lab V The concrete is of sufficient richness 1 to prevent percolation of ot water ter after alter it itIs to Is properly mixed and placed but as us usan asan an 1111 additional safeguard the t specifications require the whole interior to tn be coated Gated with a rich cement coating UnG Division of Water About a 0 mile from the upper upp end of the conduit will mill iII be located what is termed the dividing station AU All waters of the Big Cottonwood areek aek during the low water season willbe will Ue be diverted into the conduit and aud at the dividing station the portion which has as not been acquired from the farm farmers farmer s will be beo turned tamed back into the nel of or the creek This will be accomplished au automatically automatically automatically by heir a specially steel ell ly ix weir with a movable partition This partition can be set se so iJ that it will wm di divide divIde divide vide the water liter independently of the total quantity vowing flowing The execution of this large pro jet t involves the moving of about O cubic yards yard of ot earth arUa excavation and atul excavating about bout cubic yards of solid rock IO k The llie total of ot tunnel is 18 1700 feet teet and the amount of ot con concrete concrete crete rete called allied for is III cubic yards There will wUl be used send to reinforce this tins concrete over ov r of ot steel barn b bet tl re reThe The Contract t ct calls cafe for the completion of this thin tank by July 16 15 1113 and for Cor every day d y that the N r remains rf mains un Unfinished finished after this da dai f ti l tractor will be penalized 1511 Q 1116 He other hand he be will receive e elve a of I for each dl day that h he com completed lele the work before this datA t I |
