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6.4 Swale /Draincie 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. These situations occur where: 1) small natural drainages or swales <br />(with gentle slopes) collect tailwater drainage from the surrounding irrigated fields; 2) shallow <br />ground water, augmented by irrigation, daylights along exposed bedding planes or fractured <br />rock to form seeps and boggy areas; 3) shallow water conditions exist along the borders of <br />ponds and depressions in channels. Because of the variation in site specific water regimes <br />within the type, three components occur within the type: 1) Dense thickets of coyote willow <br />( Salix exioua which occur primarily adjacent to the west lateral CC Ditch. 2) Less well- drained <br />areas, or areas where standing or slow - flowing water occurs during much of the growing <br />season, support vegetation that is dominated by phreatophytic and hydrophytic graminoids <br />(carices, rushes, and sedges). 3) The least well- drained areas, or areas where standing water <br />persists, are dominated exclusively by thick stands of cattail (Typha latifolia also a perennial <br />graminoid). <br />The graminoid- dominated component characterizes the Swale /drainage type because of its <br />greater areal extent (approximately 95 percent of the type) than the other two components and <br />its potential grazing utility. Cattail occurs primarily adjacent to stock ponds and in tailwater <br />drainage ditches. Willow is primarily restricted to the banks of the west lateral CC Ditch. <br />Where significant areas of cattails and willows occur, they form islands or stringers within the <br />graminoid component. <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 CDMG <br />regulations. However, density data in the willow thickets was collected. No data was collected <br />from the cattail component. Both the willow and cattail components function primarily as <br />wildlife habitat (see Section 2.04.11, Fish and Wildlife Resources Information). The cover and <br />frequency sampling results for the graminoid component are summarized in Table 2.04.10 -19. <br />Total vegetation cover was estimated at 59.0 percent (Table 2.04.10 -19). The cover of litter <br />and bare ground was 40.8 and 0.2 percent, respectively. Hydrophytic graminoids comprised <br />Revised September 2010 (PR 06) 2.04.10 -66 <br />