Incidence and Management Costs of Freshwater Aquatic Nuisance Species at Projects Operated by the U.S. Army Corps of Engineers

Abstract

Abstract : This study investigates the costs and possible benefits associated with freshwater aquatic nuisance species (ANS) at projects operated by the U.S. Army Corps of Engineers. Based on results from a random-sample survey of three Corps Divisions (LRD, NWD, and SAD), ANS occurred at 16.9% of Corps projects and ANS management costs were incurred at 10.5% of the projects ($4,165,500 total expenses). Most ANS occurrences were large aquatic plants, which incurred 98% of the management cost. Algae management made up most of the remaining cost. Based on a literature review, Corps expenses are a small fraction of the total ANS management expense in the United States. Florida management costs are among the best documented and are over 40 times the Corps expenditure in Florida. Corps costs per unit effort are lower than average. If the benefit-to-cost ratio found for Florida in the ANS literature generally applies, the benefits derived from Corps ANS management are about $35 million per year in the Jacksonville District alone and $50 million per year in the surveyed Divisions. Benefits from improved habitat for threatened native species may also be substantial, but are poorly estimated.