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<br />N <br />~ <br />Ul <br />-.1 <br /> <br />data for the particular event were not available to make the <br />comparison. sometimes the flumes became silted, making the data <br />questionable. It has also been observed that the float and <br />stilling basin need some adjustment and realignment which will be <br />done during the off-season for the existing system and changes done <br />in new fabrication. Wild animals like raccoons love to play with <br />the equipment and were evident from their footprints left on the <br />equipment. Necessary caging of the equipment will be done next <br />year. <br /> <br />The total area monitored included 415 acres of conventional <br />irrigation and 304 acres of surge irrigation; the attached list <br />shows the sites. A few fields were excluded where data collection <br />became a problem. <br /> <br />The SCS monitoring team also collected data from two surge <br />demonstration sites for total inflow and outflow water measurements <br />for the total fields. Those data will be used to compare the <br />results as soon as available. <br /> <br />Results and Discussion <br />Delta-Montrose <br /> <br />The results shown under Data Sheet, Table I, are from nineteen <br />irrigation events that. yielded usable data out of thirty-nine <br />monitored at Delta area. Deep percolation was reduced by 145 acre <br />inches in 194 acres of surge irrigated area and this resulted in <br />salt load reduction of 666 tons. The slat factor used to convert <br />the deep percolation data was 0.337 ton/acre inch. This was taken <br />as an average value for the entire basin covering all watershed <br />area. The results from Montrose area shown in Table II, are from <br />thirteen irrigation events that yielded usable information out of <br />thirty nine monitored. Nine fields out of fourteen in the Delta <br />area provided reliable data. similarly in Montrose eight fields <br />out of twenty provided the most reliable data. Deep percolation <br />reduction of 104 acre inches in Montrose area made it possible to <br />achieve a salt load reduction of 387 tons of salt. <br /> <br />The principal causes of having unusable data include cross-over <br />flow coming to the outflow flume showing excessive run-off much <br />higher than the inflow, siltation of stilling well, displacement of <br />the pulley from potentiometer due to strong wind or disturbances <br />created by small animals. There were instances where surge <br />irrigation tended to under-irrigate. The field #06 in Table I and <br />M2, M4, and M6 in Table II under surge irrigation show negative <br />deep percolation indicating deficit irrigation. This could be a <br />real concern in surge irrigation. This could also have been due to <br />the assumption of higher soil moisture deficit. Soil moisture <br />deficits (SMD) were established on the basis of SCS data on water- <br />holding capacity minus a generalized fifty percent management <br />allowable depletion. In the future SMD will be closely monitored <br />by use of soil probe, gypsum blocks, etc. The depletion will be <br />checked by tracking the ET data as well. There is a weather <br />station that will help to calculate ET. This year (1992) the <br />farmers tended to irrigate in their own way most of the time, <br />although efforts were made to make them understand the ill effect <br /> <br />4 <br />