Environmental Conditions, Irrigation Reuse Pits, And The Need For Restoration In The Rainwater Basin Wetland Complex, Nebraska

Many of the processes of social and economic change in rural areas of America in the last century have had significant negative environmental impacts (Woods, 2005). The conversion of native grasslands and woodlands to farmland is a phenomenon that has been observed the world over (Foley et al., 2005). The growing demands of agriculture have transformed land cover at a global scale (Goudie, 2006). It is estimated that, globally, grasslands have lost approximately 19.4 million sq km from their pre-agricultural extent. According to Goldewijk (2001), in the past 300 years, areas of cropland and pasture have increased by around five to six fold. The loss of wetlands on a global scale is cause for serious concern. Wetlands cover about 6 percent of the earth’s surface, even though they tend to occur in relatively small and often geographically isolated patches. However they also are responsible for about one quarter of the Earth’s net primary productivity, and provide crucial wintering, breeding, and refuge areas for wildlife (Goudie, 2006). With these facts in mind, it becomes even more alarming that the world has lost up to 50 percent of its wetlands since 1900; the United States alone has lost approximately 54 percent of its native wetland habitat, mostly through the conversion to farmland (Goudie, 2006)

Correlating climate with late-winter wetland habitat in the Rainwater Basin, south-central Nebraska

Master of ArtsDepartment of GeographyJohn A. Harrington JrThe Rainwater Basin Wetland Complex of south-central Nebraska is a region of great climatic variability, as well as tremendous ecological importance. The Rainwater Basin Wetland Complex is located at the focal point of the Central North American migratory bird flyway, and supports in excess of twelve million birds during the spring migration period. The physical landscape has been significantly altered from its pre-settlement state by agricultural conversion via the draining of over ninety percent of the native wetlands. Due to the region’s highly variable continental climate, interannual wetland water levels are also highly variable and currently unpredictable. I have used multi-year analysis, including the construction of a regional water budget assessment, to study which climatic variables play the most crucial role in the late-winter filling of wetlands. Research objectives were met by analyzing ten cold season (Oct – Feb) climatic variables and an annual measure of wetland area for five years, in order to better understand possible climatic drivers of wetland hydrologic functioning levels in March. Longer time series of winter season climatic information were also assessed to help place the recent and more detailed analysis into a longer climatic context. Research results will aid local management agencies in the future through enhanced knowledge of how climatic variation impacts wetland function. Seasonal precipitation and temperature was favored by the linear regression analysis, while the multiple regression analysis placed higher emphasis on February evapotranspiration rates, February snow depth, and February snowfall. Lastly, the hydrologic water budget that was created for the study area had several highly correlated output variables with basin-wide flooded hectares, particularly annual snow storage