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5.4 Swale /Drainage Type (IPSW) Flood irrigation of lands on and adjacent to the study area <br />has created water regimes in certain locations that favor the establishment of hydrophytic and <br />phreatophytic vegetation (see Attachment 2.04.10.-5, Figure 4 -5, formerly Peabody Appendix <br />10 -4). These situations occur where: 1) small natural drainages or swales (with gentle slopes) <br />collect tailwater drainage from the surrounding irrigated fields; 2) shallow ground water, <br />augmented by irrigation, daylights along exposed bedding planes or fractured rock to form <br />seeps and boggy areas; 3) shallow water conditions exist along the borders of ponds and <br />depressions in channels; and 4) stable conditions occur on portions and banks of the two <br />streams draining the study and surrounding area (Calamity Draw and Tuttle Draw). Because <br />of the variation in site specific water regimes within the type, three major components may be <br />delineated. Dense thickets of coyote willow ( Salix exigua occur on shallow, slightly elevated <br />sites along the drainages where better - drained conditions exist (see midground of Figure 4 -3, <br />Attachment 2.04.10 -8, formerly Peabody 10 -4) or in areas surrounding seeps with similar <br />conditions. Less well- drained areas, or areas where standing or slow - flowing water occurs <br />during much of the growing season, support vegetation that is dominated by phreatophytic and <br />hydrophytic graminoids (carices, rushes, and sedges). The least well- drained areas, or areas <br />where standing water persists, are dominated exclusively by thick stands of cattail (Typha <br />latifolia also a perennial graminoid). <br />The graminoid- dominated component characterizes the swale /drainage type because of its <br />greater areal extent (approximately 80 percent of the type) than the other two components and <br />its potential grazing utility. The remaining two components generally occur in the eastern half <br />of the study area and almost exclusively in the proposed permit area. Small isolated <br />occurrences of cattails and willows may occur in the western half of the study area. Where <br />significant areas of cattails and willows occur, they form islands or stringers within the <br />graminoid component. Where all three components occur together, they form a relatively <br />complex mosaic (see Attachment 2.04.10 -8, Figure 4 -5, formerly Peabody Appendix 10 -4). <br />Vegetation cover, frequency and herbaceous production samples were concentrated in the <br />graminoid component of the swale /drainage type primarily because of measurability and the <br />fact that this component comprises the majority of the type. The willow component has a <br />closed canopy and measurement of the production of shrubs is not required by OMLR <br />regulations. However, density data in the willow thickets was collected. No data was collected <br />(Revised October 2009) 2.04.10-48 <br />