Show at WIN r 7 M of n A sv V gi A Z en R v 0 9 4 4 15 ar 43 4 V A R G ir RV W M M A A 41 e e 9 A d r 4 A il raising water by for irrigation in egypt I 1 prepared by tho national geographic So society clety washington D C to increase crops or make them possible Is a worldwide procedure but the ways in which the priceless water Is a gotten on to thle soil in various parts of the world varies from tho the primitive gourd flipped dipped by hand to the costly enga engineering project while american farmers on hitherto arid areas of the west aro having their water delivered to them for irrigation purposes chinese farmers known the world over for raising from one to four crops a year on their less than an acre plots are arc still using devices which antedate the windmill by many centuries the plains of szechwan Sze chwan province are dotted with huge water wheels which resemble tin the ferris wheels nt state fairs however wever a ride on a chengfu irrigator would be a ml bit damp for water cups and pipes occupy the space where seats would be if the wheel were in an amusement park As the wheel turns the cups dip water from the canal when the containers reach the level of the field the water Is discharged into a trough troug li neighboring farmers whose plots ap benr as productive as those of the owneta of water wheels often have no visible risible means of lifting water to their deeds gelds but inside one of their thatched huts a blindfolded cow ox or horse Is wearing a circular path around u targe large wheel which performs the work in chlell province even within sight of Pel helping ping farmers irrigate their farms largely by foot power one le de vice consists of a long open trough with ith one end in the canal and the oth er on the edge of the farm three or four chinese boys tread spokes ing ng froni from a huh hub which revolving causes a chain with loose hoards boards attached to push water from the annal through the trough until it reaches the tloyd something like a windmill perhaps the lie nearest oriental ap to the windmill Is the pumping apparatus used at the salt works at taku near china it resembles the framework of a huge cylinder with eight vertical ertl cal sails about 0 by 10 feet because Lo calise at least one of the sails Is always in n the wind this type of pump though crude compared with the expensive windmills of eu cu rope Is almost constantly working Jap japans tins foot pump li 19 a one ninn man affair instead of treading spokes the in japanese farmers tread the paddles of the irrigating wheel korean fa farmers are content with thir th ir scoops which tire ne tied ded to tripods placed on the bank of a stream when the scoop Is tilled filled with water it Is hoisted to the field and emptied the cradle irrigator Irrl gator Is atso alo a pop alar device among the koreans tins this Is a long trough on a narrow rim of I 1 earth between the water and the field when the cradle Is dipped into the water it Is so balanced that one man cun can seesaw it until several gallons of water gush on the farm african water supply systems range from gourds geurds coar cn on the herds bends of native women to the i great aswan dam which controls the nile flood waters drifting down the nile however the trav traveler eler sees several interesting con tri vances used by the natives to nug aug csont the natural irrigation of the nile valley the the most commonly used device consists of a wooden 11 11 ll II the uprights of which tire are driven deep into the river bank on the crossbar cross bar liar between the uprights a long pole Is balanced the end over the water bear a reed basket while on the other end a clod of mud nets acts as a counterbalance now and then one sees an ancient archimedes screw screw this device resembles a cross section of the smokestack of the nile river steamer an augur like inner segment raises water from the over liver and discharges it on the river bank in much the same manner manlier as a carpenters augur discharges from a hole in a board the persian fenian water wheel resembles wheels used in our northwestern states until the early part of this century on the sites of several western don projects water wheels similar to paddle wheels on ohio river boats pumped water for irrigation purposes i in remote districts some of the old wheels tire are still in operation irrigation system in india among the indians indiana of the west the tribal womenfolk still carry water jars on their heads in much the same manner as the natives of central africa irrigation has greatly developed the drier parts of india the greatest recent development Is on indus river unlike the famous aswan dam across the he nile and such well known Amer american lenn structures as the clephane Cle butte roosevelt and pathfinder dams the heart of the indus irrigation Irrl gutlon system Is a barrage not a data dam both barrages and dams dains work toward the same end to help get river water on the land but they go about it in somewhat different Verent di ways the barrage Is a low darn dam over or through which the water continues to how flow its function is to raise and keep the water at a certain height so that part of it will run ot oft into canals on the river banks the remainder goes tumbling over the barrage and on down the river bed the barrage Is in a word a colossal elder brother to the diversion weirs that turn water from main canals into minor channels the dam on the other hand Is primarily a storage structure that creates a n great reservoir in which the entire river now flow for nabeh of the year Is held captive until tha dry season when it la Is needed in the valleys below then the stored water Is fed out through sluices biggest barrage in world the indus barrage barr built near suk hur 1 ur in the Is the greatest barrage in the world both in length nl al moat a mile tind in the amount of water diverted seven canals will low flow out on the level created by the new structure and will furnish water estimated to be enough to irrigate six million acres of land now barren this Is a region greater than the entire area of massachusetts two of the canties on the right bank of the river will he be wider than tile the suez canal and one ol of the waterway waterways on the left bank will lie be nearly half a as brond broad ng again aln the remaining channels will he be narrower but will carry mighty streams themselves thew selves I 1 among existing irrigation structures the aswan dam dain across the nile la Is often pointed to us na the greatest in point of length it probably Is since it Is one and a quarter nilles miles from abutment to abutment its feet of height liel glit however Is overtopped over topped hy by at least five american Ani erlean irrigation data dams Arro idaho 34 feet shoshone Sho hone wyoming elephant butte new mexico fg roosevelt arizona aso and pathfinder wyoming in the matter of the he amount of water impounded world honors among arti reservoirs should probably go to the elephant butte deim am naros the aitto grande river in new mexico such measurements are best made in the number of acres the water would cover one foot deep tile the capacity of i the elephant butte reservoir la is more than acre feet grenter greater than that created by tile the aswan dam |