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2) Terraces: Sediments associated with the inactive <br />portions of the stream channels, particularly those at <br />much higher levels have been categorized as Quaternary <br />Terraces. These terraces are most likely not associated <br />with Pleistocene glacial deposits which are found at much <br />higher topographic levels along the Colorado River. <br />In some areas, these deposits blend into the colluvial <br />sediments, making it difficult to distinguish between the <br />two geomorphic features. <br />3) Colluvium: colluvial deposits are considered to be all <br />loose, heterogeneous rock masses composed of soils and <br />rock fragments which have been deposited chiefly by mass- <br />wasting, usually at the base of steep slopes. Also, <br />colluvium may be deposited by unconcentrated surface <br />runoff or sheet erosion, again usually at the base o£ a <br />steep slope. In the permit area, colluvial deposits are <br />found along the base of the main hogback between the <br />terrace material and exposed bedrock and blanketing much <br />of the bedrock along the south facing portion of the <br />hogback (Figure 5.1-1). The latter colluvial area is not <br />shown in Figure 5.1-1, since they are not associated with <br />possible AVF's. <br />5.1.3 Colorado River <br />5.1.3.1 Unconsolidated Sediments <br />As would be expected for a major river system, a full range of <br />sediment sizes and types can be found along the Colorado River. <br />Due to both down-cutting and man-made structures, the active <br />channel of the river is restricted to a narrow portion of the <br />valley. Terraces and alluvial fans of tributaries make up the <br />largest portion of land in the valley. Nearly all agricultural <br />NCEC - Coal Ridge ~1 5-2 ABC/1145/900301 <br />• <br /> <br /> <br />