Show t Western Resources s t WRAP WRAP-UP t t Ml ci l I l ll l ll J Mohawk on water use The reason why people want our water is that it is just as steady a flow this year as last year and the years before tha C. 1 C. L L. L Gould Manager Wellton Mohawk Irrigation and Drainage District Wellton Ariz The Wellton-Mohawk Wellton Irrigation and Drainage District east of Yuma Ariz is hunkering down to get better use out of the feet acre-feet of water that it gets each year from the Colorado River Reason Central Arizona Indians and others have cast covetous eyes at Wellton- Wellton Mohawks Mohawk's firm Colorado River water supply C. C L. L Gould manager of Wellton- Wellton Mohawk is quietly outraged about the continuing criticism of Wellton-Mohawk's Wellton use of water He claims and he has support support support sup sup- port for his iris claims that Welton Mohawk is one of the most productive irrigation districts in the country Maurice N. N Langley an expert on the technical and scientific aspects of irrigation who worked closely with the Wellton-Mohawk Wellton district from the time it was created in 1951 until he retired from the Bureau of Reclamation in the mid regards Wellton-Mohawk Wellton as among the more efficient irrigation districts in inthe in the West The Bureau of Reclamation lists Wellton-Mohawk Wellton as a highly productive area whose principal crops are alfalfa hay alfalfa seed barley oats vegetables and citrus fruit Eight alfalfa hay crops can be and often are grown on Wellton-Mohawk Wellton lands annually Double-cropping Double of other crops is common The district has several large feedlots and Iowa Beef Processors Inc has discussed opening a plant in the area This correspondent on a recent two-day two visit to the Yuma area saw thousands of acres of obviously healthy crops being grown in the Wellton-Mohawk Wellton District Cotton and lettuce crops were being harvested harvested har har- har vested in November mid Farmers in the district were growing a half dozen different different different dif dif- dif dif- ferent types of citrus crops walnuts and dates grains specialty seed crops vegetables such as okra carrots and onions and lots and lots of alfalfa hay They have large investments in both cattle and sheep Western Resources Wrap-up Wrap saw several types of water-saving water operations going on at Wellton Mohawk The most m t interesting is what the local farmers call cali swapping soil which means farmers bring new better soils in from sites where no crops are grown and put up to two feet of the better soils over their less productive soils solis Sometimes the poorer soils are scraped off first but this is rat not usually done The Soil Conservation Service experts of the US U.S. Department of Agriculture are available to help Wellton Wellton- Mohawk farmers select the soils solis that they want to use for swapping soil but the farmers usually do the selection themselves them them- selves Jim Naquin a Wellton-Mohawk Wellton farmer who has expanded his fathers father's 80 acres of holdings to acres owned by the Naquins with additional acres leased eased showed slowed this correspondent how he makes his soil selection lie He looks for Cor loamy soil with good water-holding water capacity By running soil samples through his ringers lingers he be can tell by sight touch and experience the top quality soils from the coarser soils solis Under his expert guidance even a non non- lOlls oils non expert can tell the difference Soil swapping appears to have great potential not oot only on Wellton-Mohawk Wellton to reduce the present ever salinity In the soil but brit also to assure that top lop quality soils are on cropped land everywhere Another water-saving water method is land land- This was going on at several oca lions while we were looking at Mohawk lands A farmer attaches I levelling land-levelling device with a laser beam o his tractor When he finishes scraping ala lis field the top soil is s quite uniform and andIe IB Ie will wilt get more efficient use Uie of his water Among the values that Wellton-Mohawk Wellton farmers have found in leveling land-leveling are that the fields fieldS' are easier to care for hence take less labor as well as s less water according to Gould A uniform field allows for more uniform application of both water and fertilizer and res results in more uniform crops Wellton-Mohawk Wellton farmers have found levelling Laser is a recent development at the district but it became so popular bec because use of its potential that economies economies that everyone tried it at least once Gould said A third method being used to save water on Wellton-Mohawk Wellton is the Irrigation Management System or IMS being sponsored by the Bureau of Reclamation This is a computer based method to determine when to schedule irrigation The Bureau has supplied several al neutron probes for field use in simplify the gathering gath of the required data for the computer and to measure the efficiency efficiency efficiency ef ef- ef- ef of of- water used in a field or on a crop By providing periodic moisture measurements the neutrOn neutrOn- probe identifies identifies iden iden identifies the meat wh which ch irrigation r t should r v 1 It L 9 Gregory W. W Brockman j of Reclamation sol specials special's specialist b based sed in yuma Xuma is with eVal cial l Wellton Wellton- working se sev Mohawk farmers mer in t the e ex experimental use of the neutron probe abbe f He lie is ts very on the U neutron pr probe lie p d for field use ti ft r i i spiel s a a research b D Campbell an irrigation c consultant nt t two jearS ears g By use of of the H obO we we c u i get the use of water use S of oc t tW probe we can ean track on t k t week basis iJ i hof d moisture content in inthe the soil We o We graph grap soil il moisture content agai against t t 4 determine e h ula the optimum tim time at whim a crop should uld be irrigated irrigated- Br tI Q t R f i oJ ft 1 j N PUQUE E EXP Brockman wa enthusiastic Sl ll a farmer with V whom ha M lied had c carried on on ona a a neutron probe experiment ent had rec recently produced a beautiful ea prop crop of cotton with the use of ci Jess than f feet of water per acre Most irrigators I rl tors' tors were ere using much more wa water ter for their crops Another farm operation on Mohawk had brought a neutron probe to incorporate into its own irrigation sch scheduling system he said Brockman said J he was sure sure sur the neutron probe would prove that better crops could be grown in the with the application application application ap ap- ap- ap of less water Gould was more reserved about it lt He tie said sid he thought it would I. I be used as an irrigation tool toot at Mohawk and that it might play a bigger role in other irrigation districts which are less efficient Campbell and two other Bureau of Reclamation officials Roy D Dt Gear and Arnold S. S Dransfield explained the value of coordinated delivery of or water and also the use of the neutron probe proof in irrigation scheduling at a meeting of the American Society of oC Civil Engineers in 1976 Studies which they had condu conducted too at Wellton-Mohawk Wellton and elsewhere in 1975 indicated they said that consistent timing alone could improve water use efficiency by more than 10 13 percent Irrigation managers of farms in 11 the area had told the Bureau of Reclamation team they Uley consistently order ordered d more irrigation water than needed and ahead of schedule to be sure they hey would have it when needed for irrigating sensitive crops Their studies indicated a neutron probe could accurately measure soil soll moisture depletion yield values of transient water use by plants as well as transient water loss by drainage These two wo values together divided by the water applied yield the efficiency for the field A coupling of neutron probe irrigation schedules with system deliver delivery capacity can lead to a coordinated delivery of water to make most efficient use of both irrigation and drainage systems while improving water use Uie efficiency and reducing farm irrigation labor costs coots the Bureau of Reclamation team reported last year at an ASNE meeting in San Diego The reason why Designer Campbell and User Brockman are so high on the neutron probe is that it markedly increases the accuracy of computer irrigation schedules and th the data stored in the computer Errors in the neutron probes probe's measurements show up in the graphs that are kept according to Brockman Brockman Brockman Brock Brock- man even keeps graphs on irrigating the lawn at his office and that of a nearby school to test lest the accuracy of the neutron probe To get a reading from the probe he merely places the two-foot two long scaler sealer with witha a shield into the ground then he puts the measurement on a graph Persons must be trained to insert the probe properly and to allow for weather changes and other variables its not work for dron drones 4 11 SAL SALINITY IN SOIL WATER Salinity in the water and salinity in the soil have been the bane of the Wellton- Wellton Mohawk farmer for many years The Gila River runs through the Wellton-Mohawk Wellton District and it joins the Colorado River about four miles east of Yuma Indians were using Gila River water for irrigation when Spanish explorers first came into the area in In 1540 So did the white settlers who came cam in as homesteaders until about 1915 when they began to drill wells to provide irrigation water for their crops By 1934 excessive salt began to show up in the well water and also in the soil due to drainage problems resulting from use of ground groundwater water for irrigation Then the water table declined alarmingly because of heavy upstream diversions of the Gila River and the l large rge number of wells drilled along the Gila Following two project authorizations in 1937 and 1947 in 1952 Colorado River water was brought in to rescue Wellton Wellton- Mohawk farm lands feet acre-feet was diverted into the Wellton-Mohawk Wellton Canal System from Imperial Dam on the lower Colorado This brought on new salinity problems Th The Wellton-Mohawk Wellton project land development took place when the Upper Colorado Basin reservoirs started to fill sharply diminishing the flow of the Colorado River and increasing its salinity content By 1961 the salinity in the Colorado River at al the International Border was nearly 1500 parts of salt per million parts of water up sharply from pp inless than a decade Also the water table began to rise again with the introduction of the Colorado River water on Mohawk Wellton-Mohawk lands and salt spots began to show up on lands along the Gila This caused more drainage problems for Wellton-Mohawk Wellton farmers Following Mexico's protest in 1961 because the salty drainage water from Wellton Mohawk t hawk was going into Mexico numerous steps were taken by this country to improve the quality of Colorado River water that the United States must send to Mexico annually under the 1944 Mexican water treaty although the treaty was silent on water quality Under legislation passed in 1974 1 this country authorized the construction of a desalting plant near Yuma to desalt Mohawk Wellton-Mohawk drainage water going to Mexico It also authorized the federal purchase of acres of the themore themore themore more marginal lands in the Wellton Wellton- Mohawk project t thereby cutting it back from to acres Although the salt spots on Wellton Wellton- Mohawk lands are clearly visible from a sm small U plane the salinity content in the districts district's soil is decreasing about three e percent annually according to Gould Its land is improving but now Wellton Mohawk has new problems This year a abiU abill abill bill biU was reallocate Wellton Wellton- Mohawks Mohawk's feet acre-feet of Colorado River water to Central Arizona Indians and the Interior Department announced its plans to enforce the acreage limitation and residency requirement of the 1902 Reclamation Act on federal projects like Wellton Mohawk Although the bill is dead and the Interior plan will be tied led up in incourt incourt incourt court both actions have made land values uncertain at Wellton |