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SUMMARY (Continued) • Agricultural practices Under the no-action alternative, the operation of the present canals and laterals and drainage systems would remain about the same as at pres- ent. Some on-f arm irrigation systems would be improved through the U.S. Department of Agriculture salinity control programs. Land leveling and field enlargement would continue, causing more modern farming equipment and irrigation practices to be used. lSither alternative A or B would complement the on-farm program of the U.S. Department of Agriculture by providing a reliable and manageable irrigation water delivery system. The improved systems would have the potential to increase crop production and/or net returns, but this in- crease has not been quantified. Design, sizing, and layout of laterals will be made in cooperation with the Soil Conservation Service to assure compatibility with the U.S. Department of Agriculture on-f arm improve- ments. Operation of irrigation systems Under the no-action alternative, the operation of canals and lat- erals in the Grand Valley would be expected to continue as at present; however, by developing either alternative A or B, existing systems would require major changes in their operation, maintenance, and replacement • practices. To further ensure salinity benefits as well as the integrity of the system, additional operation, maintenance, and replacement costs would be incurred. Soils No significant change in soil or erosion conditions is anticipated under the no-action alternative. Seepage reduction as a result of. canal and lateral improvements under alternative A or B would lower water tables and subsequently reduce the upward capillary movement of salt carrying water, thus decreasing salt deposits at the land surface in some areas and increasing crop growth. Properly applied irrigation water could then contain the salt below the root zone, resulting in better crop growth in the long term. The actual improvement in crop growth cannot be quantified because of many variations in drainage conditions, soil types, and irrigation prac- tices. During construction of either alternative A or B, erosion would be a problem when vegetation was cleared and soils were exposed to wind and water. Construction material sites along washes could constitute special problem areas if the channels of the washes were disturbed; however, these sites would be developed with buffer zones along the washes to alleviate this problem. S-5