Documentation of Existing Conditions in the Central Platte Valley

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SECTIONTWO Enuironmenni Setting PEMA, 10 percent PEMC) on the NWI maps. Individual areas of mapped PEMA or PEMC do not exceed 50 to 200 acres in any other portion of the study area. Some large areas of grassland with interspersed channels of PEMA or PEMC occur in a number of areas on islands and along secondary channels away from the river. Mapping of wet meadows and bottomland grasslands within the study area is being completed by BOR as part of the GIS database. Maps with this information will be included as an appendix in a later version of this Baseline Report. A preliminary identification of the locations of significant areas of wet meadows was developed, based on review of the NWI and WELUT maps, and is listed below. This list includes both areas of wet meadows and bottomland grasslands with interspersed wet meadows or marsh vegetation. • Lower Wood River Valley and areas north of the Platte River in Segment 1 (partly included in WELUT acres) • Mormon Island and Indian Island (Segment 2 -3) • Some areas immediately south of the South Channel (Segment 3) • Large parts of Shoemaker Island (Segment 34) • Areas adjacent to the North Channel of the Platte River (1.5 to 4 miles north of the South [main] Channel) in Segments 3 through 6 (not included in WELUT wet meadow acres) • Areas adjacent to the South Channel of the Platte River on the south side of Elm Island (Segments 5 through 7) • Portions of Clark Island (Segments 6 and 7) • Large portions of Fort Farm and Kilgore Islands (Segments 7 to 8) • Large areas along the North Channel (Segments 9 to 10) (not included in WELUT acres) • Some areas along the South Channel (0.5 to 1 mile south of main channel) and south of the Platte River (Segments 10 to 11) • Portions of large islands (Segment 11) • Parts of Jeffrey Island (Segment 12) (partly included in WELUT acres) 2.7.3 Hydrology and Ecology The Central Platte River Valley is underlain by an unconfined, shallow, alluvial aquifer (Hurr 1983). Soils consist of permeable or very permeable sandy and gravelly soils that are poorly drained or very poorly drained. In general, areas within the floodplain are subirrigated, have a shallow ground water table within 2 feet of the surface in depressions and meadow channels, and are 2 to 5 feet below the land surface in grasslands during the spring (SCS soil surveys: Brown et al. 1978; Bowman et al. 1973; Buller et al. 1973; Pollock et al. 1981; Ragon 1974; Vanek et al. 1985; Wahl et al. 1984). Common soil series within wet meadows and wet meadow complexes include Platte, Alda loam, Gibbon silt loam, Leshara fine sandy loam, Wann fine sandy loam, and loamy alluvial land. These same soils also occur in many areas up to a mile or more on =Ombw Wocd*wggyde feft-MServim 68FOD9728600 /rl.doo 6W1999(9:52AM)/URSGWCFS12 2-9