WSP04498 - Laserfiche WebLink

Home Browse Search

~~ .-4 C"? ,-, ....,., ",,..- '-' . CHAPTER VI PLAN FORMULATION Components from the two broad alternative categories--conveyance system seepage reduction and canal systems combining--were used to formulate five representative alternatives. These five alternatives are groupings of the most promising salinity control increments. Each increment within an alternat ive is autonomous; that IS, each could be constructed independent of any other increment. Individual increments involved either concrete lining or placing laterals in pipe, concrete or membrane lining canal segments, installing barrier cutoff walls ,.U or combining irrigation systems. Separate increments were selected based on the assumption that entire lateral systems and unbroken, major segments of canals would be improved because it lS difficult to attribute salt loading to smaller specific sections of canals and laterals and because administrative and operational problems make improving small segments impract ical. All the representative alternatives were determined to be nonviable since each one included a canal combination and/or seepage cutoff barrier increment. Canal combination was a nonviable salinity control measure because various water user representatives repeatedly emphasized that any plan which included a form of canal combination would not be acceptable. The use of barrier cutoff walls was considered ineffective because it is not a demonstrated method of salinity control; however, some work could be done during preconstruct ion studies to determine the suitability of a barrier cutoff wall for salinity control. 1./ The barrier concept involves the placement of an impermeable material within the downslope canal embankment. The material would function as an underground dam, impeding canal seepage from moving downgradient toward the Colorado River. 62