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<br />. SUMMARY AND CONCLUSIONS . <br /> <br />1. SCS and USBR started out coordinating their planning efforts in a desirable <br />manner, but then something happened and it appears that coordination became <br />less effective. I believe that SCS got ahead of USBR and therefore, the <br />information exchanR8 was not synchronized. <br />2. SCS is to be commended on evaluating the study area by subunits and prior- <br />itizing these subunits for implementation. Also, for including the Navajo <br />unit which is south of the Aztec Divide. <br />3. 'lbe SCS water budget does not consider all of the factors that contribute <br />to a more complete water budR8t. It is difficult to compare the two budgets <br />and there are si-'!rlif1cant differences. The USBR budget is more complete. <br />For the "present" or "pre..project" condition, farm delivery is 77,400 ac. ft. <br />in the USBR budget and 105,000 ac. ft. in the SCS budget. For tailwater <br />runoff, the USBR value is 9,660 and the SCS value is 45 ,000. SCS appears <br />to have developed its budget ....i thout full consideration of the extensive <br />reuse taking place. This probably accounts for the difference in delivery <br />and tail_ter runoff figures. Also, SCS did not seem to take into account <br />the onfarm improvements that have recently been installed or are being <br />installed. Possibly this is due to the time lag between data collection <br />and report preparation. As an evaluation tool, I attempted to develop my <br />own _ter budget that appears on page 15. My budR8t ShOWlS an increase in <br />farm delivery rather than a decrease. <br />4. Despite the questions raised on the ....ater bud~t, the SCS estimate of salt <br />load reductions is ....ithin the tolerance that can be expected, given the <br />many variables to be considered and the lack of "hard" data on these variables. <br />Assuming the same concentration of outflo...., my water budget gives a salt <br />load reduction (see page 21) that is within 10lt. of that calculated by SCS. <br />However, there is still some question as to what drain flow concentration <br />should be used in salt load reduction calculations. It is recommended that the <br />hypothesis be accepted, based on the data available at this time, that the <br />dissolution of salts from the soil and subsurface materials is the principal <br />mechanism associated with salt loading, and that sait load reductions are <br />directly related to reductions in irri~tion seepage and deep percolation. <br />5. With the planned increase in sprinkler system acrea~, there could be a <br />si~if1cant increase in total evaporation. However, confirmation of the <br />quantity has not been obtained. Considering all factors, this could be <br />