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4-9 <br />SIDE VALLEYS <br />• According to the results of office and field studies, the water availability criteria necessary <br />for the inclusion of the side valley geomorphic units as an AVF are not met. <br />The surfaces of the alluvial deposits in all four side valleys do not carry any traces of <br />agricultural use in the past except possibly for temporary grazing. The vegetation cover does <br />not show any important difference compared to the vegetation cover of the uplands. It consists <br />practically exclusively of sagebrush and sparse grasses. The streams of these side valleys are <br />intermittent only and, very probably, they would not enable any flood or ditch irrigation. The <br />conditions for the subirrigation are unfavorable as can be documented by the ground water <br />measurement in the monitoring well MW4, located in the lower part of Munger Canyon. This <br />monitoring well is 40 feet deep and no ground water was found in the well. This measurement <br />was performed recently (end of April, 1981) during the period of increased precipitation and <br />snowmelt. A depth to ground water more than 40 feet eliminates practically any possibility of <br />effective subirrigation. <br />The limited extent of the alluvial deposits and their frequent dissection by the erosion of the <br />• ephemeral channels make the possibility of agricultural use of these valleys very remote. The <br />logs of four test pits that were excavated in these valleys (test pits TP-1 through TP-3 were <br />excavated in the Munger Canyon; test pit TP-5 was excavated in the McClave Canyon) confirm <br />that natural subirrigation is nonexistent in these valleys. All test pits show sandy and gravelly <br />soils extending to a depth up to 10 feet, a very thin horizon of poor topsoil, no traces of <br />mottling, and a very slight increase in moisture of these soils with depth. <br />We feel that for these reasons none of the side valleys documented at the site can be <br />classified as an alluvial valley floor. Logs of the test pits are found in Tables 4.1.1 through <br />4.1.5; and logs for monitoring wells drilled in the area are shown on Figures 4.I3 through <br />4.1-6. <br />CONCLUSIONS <br />The strip of alluvial sediments associated with East Salt Creek, as indicated. on Fgure 4.1-2, <br />can be classified as an alluvial valley floor. Although there are additional alluvial deposits in the <br />area located in four valleys that form tributaries of East Salt Creek, we do not feel that they can <br />• be classified as an alluvial valley floor because of the absence of water availability and owing to <br />other factors discussed in this section and in Section 4.2.2.1. <br />M~ Volume 1 4 - 29 - 96 <br />