2011-08-29_REVISION - M1986015 (11)

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• • by roadways, developed land, or sparsely vegetated land. The vegetation along these drainages is highly variable and dominated by cottonwood, willow, Chinese elm, and various weeds. In some places a wetland like vegetation develops, but is probably not jurisdictional. Some of these areas have silted in and are no longer functional, but the original vegetation remains. This unit tends to blend at the lower end of the drainages with the Riparian Forest. Grassland/Pasture: In some locations, pastureland is maintained for grazing purposes. These pastures are often irrigated and dominated by a rich grass growth composed mostly of introduced pasture grasses such as smooth brome. Where irrigation has been removed the land quickly reverts to primarily a weed dominated dryland. This is usually the case because the groundwater is too deep to maintain the grasses without irrigation. Shrub /Scrub: This unit is not common, but where it occurs it appears to be probable wetland. In some cases the groundwater is probably somewhat too deep to be jurisdictional, but that is marginal. These lands are often flooded by the river during heavy runoff events in the spring, but revert to a dry land for most of the summer. Such flooding might occur sufficiently long to make some of the lands jurisdictional wetland. The vegetation is sometimes dominated by Tamarix, but can also have a large willow component and some cottonwood growth. In some cases, these lands appear to be developing into Riparian Forest, but where the soil texture and hydrology favors the shrub domination, the shrub community seems to be maintained for a considerable amount of time. Thus, this unit may sometimes be successional, but not always. Wasteland/Weeds: Most of the land dominated by this unit shows evidence of long term disturbance. This is usually dry land, well above the influence of the river. The vegetation is dominated by various annual weeds, but over time, seems to develop into a desert scrub type of growth dominated by rabbitbrush and four- winged saltbush. Very little grass is ever found in these areas. The herbaceous growth is primarily composed of annual weeds. In many cases, this unit is maintained by periodic disturbance. Old Field: This unit is similar to the previous one, but is more often found in more bottomland situations. It may be dominated by annual weeds of the same species as the previous unit, but, due to a less desert-like environment and often a clayey soil, tends to produce very robust weed growth. Mixed in with the weeds are small amounts of grasses, most of which appear to be remnants of previous pasture. In somewhat more elevated locations this unit contains a large component of four - winged saltbush. Thus, this unit tends to blend floristically with the previous unit, but it definitely does not form a linear sequence. This unit tends to be present on land where pasture or farming was historically practiced; the wasteland unit rarely shows any evidence of pasture or farming uses in the past. It is primarily a disturbance maintained vegetation. River Bluff Well outside the affected land is the river bluff vegetation which exists only on the south side of the river. If there is an erosional shelf at the base of the cliff, this vegetation may have a narrow ribbon of 3