Studies at ERDC fall into two broad categories: 1) Large, comprehensive Programs, and 2) Comparatively specific, Reimbursable studies that are mainly conducted for Corps of Engineers District offices and usually apply to particular geographic areas. The list of Programs to the left contains civil and military research that includes nuisance species, aquatic plants, dredging effects, recreation management, wetlands, and environmental quality. Research conducted under Programs usually differs from Reimbursable studies in that it is directed toward larger, more compressive questions pertaining to resource management and impact assessment.