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tr. C',j ..... - c c: Most of the consumptive uses by native vegetation were supplied by ground water. Although the ground-water table ad- jacent to the streams fluctuated with surface flow, it is be- lieved that the ground-water supply along streams, which were perennial under virgin conditions, was sufficient to provide normal use by the native vegetation for average 1946-1951 virgin flow conditions. Also, flooded conditions in the channels and flood plains tend to either destroy native vegetation or retard its uses during periods of inundation 50 as to offset subsequent higher rates of use because of increases in the available ground- water supply. stream depletions by native vegetation for average 1946-1951 virgin conditions were considered to be the same as for average 1914-1945 virgin conditions for all stream sections except the reach between Nogales and Rillito on the Santa Cruz River. According to the narratives of early explorers and settlers, the Santa Cruz River was not a perennial stream under virgin conditions and the flow was intermittent for much of its length. The greater portion of the surface inflow to the stream section between Nogales and Rillito percolated to the ground-water basin and was used by phreatophytes in the reach. Therefore, the , reduced surface inflow to the stream section for 1946-1951 virgin conditions reduced the ground-water supply available to the native vegetation during the period. It was estimated that the stream depletion by native vegetation between Nogales and Rillito on the Santa Cruz River for average 1914-1945 virgin conditions was reduced for average 1946-1951 conditions directly 16