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The willow component of the swale/drainage type occurs on shallow, slightly elevated sites that <br />are better -drained than areas supporting vegetation that can tolerate standing or flowing water, <br />and completely saturated conditions. No attempt was made to sample cover in the willow <br />component because of the extremely high shrub densities encountered. Qualitative evaluation <br />indicated that the canopy and ground cover, including litter, in the willow thickets was equal to <br />or greater than 100 percent. In more open areas where the willows were less dense, <br />quackgrass, alkali muhly and common spikerush were prevalent. <br />The mean density of coyote willow, the only shrub species represented, was 78 stems per <br />meter square. This translates to 312,000 stems per acre. The density of actual willows is <br />expected to be much lower. It was impossible to tell which stem went with which individual and <br />since willow is a clonal body individuals are in determinant. These density figures do not <br />represent an average density for the swale/drainage type as a whole, but only in the thickets. <br />A total of thirty species were found in the swale/drainage type. Graminoids dominated, with a <br />total of twenty species (see Table 2.04.10-19) with ten having relative cover values of one <br />percent or greater. Annual and perennial forbs totaled ten, only one perennial forb had relative <br />cover greater than 1 percent. <br />The third component of the swale/drainage vegetation type, the cattail component, was not <br />sampled since it is only a small community. This component is nearly 100 percent cattail. <br />Standing water occurs in the component essentially all year long. The cattail component is <br />further described in Attachment 2.04.10-10, formerly Peabody Addendum 11-1 and is the same <br />as was found in 1999. <br />The extent and distribution of the swale/drainage type is wholly dependent upon the irrigation <br />associated with the surrounding agricultural areas excepting any contribution from storm flows <br />or snowmelt runoff. Undoubtedly, the ephemeral drainages could not support this vegetation <br />without the supplemental water. The contribution of supplemental water from irrigation <br />tailwater is greatest during the mid-April to October irrigation season, while ground water <br />recharged from irrigation may contribute to seeps and bogs over a greater period. <br />Each component of the swale/drainage type exhibits very high levels of productivity and cover, <br />although the vegetation supports little utility other than wildlife habitat. The surrounding <br />February 2015 (TR -66) 2.04.10-67 <br />