Documentation of Existing Conditions in the Central Platte Valley

Home Browse Search

I SECTIONTWO Environmental Setting create and maintain open grassland areas; and high diversity (100+ species) plantings on former crop fields combined with re- contouring of topography to create wetland areas. The high diversity plantings were done more recently (starting in the early 1990s) than the low diversity plantings, but are already developing vegetation that more closely resembles native sites than either the low diversity plantings or the cleared forests, many of which are more than 10 years old. The low diversity plantings have significantly greater cover of exotic cool season grasses and exotic fortis; and less cover of sedges, rushes, and wetland forbs, compared to reference sites (Pfeiffer 1998). Species richness is low, with less than 30 species. The high diversity plantings also have less cover of sedges, rushes, and wetland forbs, but many of the species are present in low numbers. Plant species richness of the high diversity plantings is equivalent to native reference meadows (120 to 150 species). The reclaimed riparian areas have cover values similar to those of reference meadows, but lower species diversity and higher shrub cover. They are typically dominated by a few wet meadow species. The Central Platte Natural Resources District, Nebraska Game and Parks Commission (NGPC), NPPD, and the Central Nebraska Public Power and Irrigation District have prepared plans for three wet meadow demonstration site enhancement projects (Anonymous 1998). The overall project goal is to assess the feasibility of creating wetlands near the Platte River using means other than streamflow. At present, two years of funding have been awarded by the Nebraska Environmental Trust Board. The three demonstration sites are: • Cottonwood Ranch near Overton (Segment 11). This site is owned and managed by NPPD and includes 140 acres of non - irrigated croplands and 20 acres of swale. The plan includes a gravity feed water pipeline capable of delivering up to 700 gpm, restoration of the existing swale, and vegetation management including seeding and control of tall wheatgrass. • Wyoming property southeast of Kearney (Segment 8). This site is owned by the Wyoming Water Development Commission and managed by the FWS. The total site is about 470 acres, of which 25 acres will be included in the demonstration project. Plans include excavations and/or hydrologic modifications in upland areas to create temporary, seasonal, and semi - permanent wetlands as well as seeding of surrounding upland areas. • Grand Island Wellfield site, south of the city of Grand Island (Segment 2). This site is owned and managed by the City of Grand Island. The project involves construction of a groundwater well system to develop a groundwater mound and provide interspersed areas of wetlands in swales, moist soils, and dry ridges. 2.9 SUITABILITY OF THE EXISTING BASELINE FOR MONITORING 2.9.1 Vegetation and Land Use The existing baseline of spatial data for vegetation and land cover types includes the 1985 WELUT database and the BOR GIS database currently being prepared. These studies are IBS GmLw MOWN V4* tederalSavkes 68FOD9728600 /ri.doc 612/1999(9:52 AM) /URSGWCFS/2 2-13