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edge of the fill area. Other topographic features include the Brantner and Brighton <br />Ditches, constructed irrigation supply canals that run from south to north through the fill <br />area. An excavated area at the southwest boundary of the fill area contains an ephemeral <br />pond fed by seepage from the Brighton Ditch and irrigation water. <br />[vegetation <br />Two vegetation communities characteristic of wetlands within the fill area can be broadly <br />categorized as sideslope seep and depression. Two sideslope seeps are located at the <br />southwest and west portions of the fill area topographically below the Brantner Ditch. <br />The depression vegetation community is located along the fringes of the ephemeral <br />depression pond at the southwest boundary of the fill area north of the state highway and <br />substation. Each community is briefly described below. <br />The sideslope seeps consists of monotypic bands of hydrophytic vegetation located below <br />the Brantner Ditch in swales along the terrace slope below the secondary terrace. <br />Vegetation is dominated by narrow-leaf cattails (Typha angustifolia) in the center of these <br />seeps, with a band of tine (Scirpus acutus) surrounding the narrow-leaf cattails, and <br />three square (Scirpus americanus), rabbitfootgrass (Polypogon monspeliensis), meadow <br />foxtail (Hordeum jubatum), and spikerush (Eleoclraris sp.) at the fringes of the seeps. <br />Vegetation within the depression area at the fringe of the ephemeral pond consists of <br />cattails (Typha latifolia), rabbitfootgrass, reed canarygrass (Phalaris arundinacea), <br />meadow fescue (Festuca pratensis), meadow foxtail, prickly lettuce (Lactuca serriola), <br />prairie cordgrass (Spartina pectinata), and three square. There is no significant emergent <br />or submergent vegetation in the pond. <br />Hydrology <br />The most significant hydrologic features within the fill area are the two irrigation supply <br />canals, the Brantner and Brighton Ditches. The Brantner Ditch is topographically above <br />the Brighton Ditch and both flow from south to north through the fill area. <br />Soils <br />Soils within the area of interest are representative of their genesis and topographic <br />position. The Natural Resource Conservation Service (USDA, 1974) identifies four soil <br />map units within the fill area. The soil units identified are gravelly land-shale outcrop <br />complex, Ulm loam (5-9% slopes), Nunn clay loam (1-3% slopes), and wet alluvial land. <br />The gravelly land-shale outcrop complex is located along the west boundary of the 611 area <br />on the secondary terrace. This complex consists of clayey soils and raw shale, overlain by <br />discontinuous gravel deposits from four inches to many feet thick. This soil type is not <br />considered hydric in nature. <br />Tucson Project Fill Area: Jurisdictional Wetland Delineation and Determination Page 2 <br />