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The results of shrub density samples conducted in the willow thickets are summarized in <br />Attachment 2.04.10-6, formerly Peabody Appendix 10-2 (Table 2-12). The mean density of <br />coyote willow, the only shrub species represented, was 10.0 individuals per meter square. This <br />translates to 40,540 individuals per acre. Each individual willow had from one to eight stems <br />associated with the crown, so the total stem density would be substantially greater. These <br />density figures do not represent an average density for the swale/drainage type as a whole, but <br />only in the thickets. In addition to the willows, approximately 14 cottonwoods (Populus <br />angustifolia and Populus sargentii) and 48 Russian olives occurred in the swale/drainage <br />vegetation type (from direct counts). The above two species occur in the drier phase or fringes <br />of the swale/drainage, or adjacent to ponds. <br />A total of 48 species were found in the swale/drainage type (Attachment 2.04.10-5, formerly <br />Peabody Appendix 10-1), indicating a higher level of diversity than is apparent with only casual <br />observation. Graminoids dominated as expected, with a total of 14 species (see Table <br />2.04.10-9) with 10 having relative cover values of one percent or greater. Annual and <br />perennial forbs totaled only slightly less at 11, yet only one perennial and one annual forb had <br />relative cover greater than 1 percent. One shrub, coyote willow, was encountered in cover <br />sampling and it had a relative cover of three percent. The swale/drainage type was less <br />diverse than the irrigated pasture type and ranked as the third most diverse type. <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 />excepting some associated pond weeds shown in the species list (Attachment 2.04.10-5, <br />formerly Peabody Appendix 10-1). Standing water occurs in the component essentially all year <br />long. The cattail component is further described in Attachment 2.04.10-10, formerly Peabody <br />Addendum 11-1. <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. The type would not persist if the irrigation system was not present, as <br />evidenced by the similar landscape in Third Park to the north where irrigation is not present. <br />Undoubtedly, the ephemeral drainages could not support this vegetation without the <br />supplemental water. The contribution of supplemental water from irrigation tailwater is greatest <br />February 2015 JR -66) 2.04.10-41 <br />