Vegetation Dynamics at the Gerald Gentleman Station Mitigation Site, Lincoln County, Nebraska

Gerald Gentleman Station (GGS), located in southwestern Nebraska near Sutherland, is the newest and largest electric generating facility in the Nebraska Public Power District (NPPD) system. In August 1994, NPPD constructed a 9.2-mile long railspur between GGS and the Union Pacific Railroad to create competition in the coal-hauling market. A multi-objective criteria analysis was used to identify a railspur route with the optimal combination of low environmental impact, favorable engineering characteristics and economic feasibility. Based on jurisdictional delineations, the GGS railspur impacted 1.95 acres of wetlands. Construction ofthe wetlands to mitigate for those impacted acres was initiated during winter 1993-94 in primarily two areas near an existing wetland complex adjacent to Sutherland Reservoir. In April, 1994, the south excavation site was seeded with a floodplain mix and the north side was left to natural vegetation establishment. The south excavation area, which was seeded, contained significantly more wetland, submergent, and emergent plant species initially, however after four years the difference in species number between the seeded and nonseeded sites was not significant. Hydrological effects from Sutherland Reservoir elevations may have played a stronger role in vegetative reestablishment and the resulting wetland plant community than any human activity such as seeding. Four years after construction, the mitigation site vegetation has re-established successfully with over 40 plant species and provides valuable palustrine habitat for a variety of shorebirds, waterfowl and other wetland fauna species.