Date of Award

January 2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geography & Geographic Information Science

First Advisor

Bradley C. Rundquist

Abstract

Since its inception in 1985, the federally managed Conservation Reserve Program (CRP) has contributed to land-use/land-cover change (LUCC) in areas throughout North Dakota. Concurrently, the Devils Lake Basin and surrounding Prairie Pothole Region (PPR) in North Dakota has experienced pervasive lake and wetland flooding. Unsurprisingly, a clustering of CRP enrollment in certain counties within the basin has occurred, seemingly coinciding with the flooding. Analysis of historical county-level CRP enrollment data pertaining to counties in North Dakota revealed that Nelson County, which is partially within the basin, has developed as a CRP hotspot in the state and has had the greatest increase in the density of CRP acreage amongst the counties in the region. We hypothesize that this high enrollment is the response of farmers losing arable lands and/or field access to the rising waters in the region, thus making CRP enrollment an economically viable option. This study uses Landsat data and GIS analysis to document LUCC and the forces driving it associated with CRP grassland and pervasive lake and wetland flooding in Nelson County. Because CRP field locations are not available from the federal government, we used multi-temporal classification techniques (three scenes per year) to derive land-cover maps from Landsat Thematic Mapper data for five growing seasons (1984, 1991, 1998, 2005, and 2011). We mapped CRP grassland at more than 90% accuracy with validation data derived from interpretation of historical aerial photography and, in the case of 2011, data gathered in the field. LUCC change analysis was done using raster GIS. We found an increase in the amount of CRP grassland in the study area between 1991 (19,688 ha) and 2005 (35,612 ha) and then a decline to 2011 (27,856 ha). Spatial analysis revealed a clustering of CRP in 1991 in the Sheyenne and Goose river valleys, likely attributable to those lands being considered of greater conservation importance. By 1998, a more diffuse pattern starts to emerge that is likely related to the wetland expansion across the county and updated federal policies regarding CRP eligibility and wetlands. The trend of diffuse distribution continued with the explosion of wetland expansion in the early 2000s.

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