Open-File Report 2014–1180
Sedimentation has been identified as an important stressor across a range of wetland systems. The U.S. Fish and Wildlife Service has the responsibility of maintaining wetlands within its National Wildlife Refuge System for use by migratory waterbirds and other wildlife. Many of these wetlands could be negatively affected by accelerated rates of sedimentation, especially those located in agricultural parts of the landscape. In this report we document the results of a decision analysis project designed to help U.S. Fish and Wildlife Service staff at the Agassiz National Wildlife Refuge (herein referred to as the Refuge) determine a strategy for managing and mitigating the negative effects of sediment loading within Refuge wetlands. The Refuge’s largest wetland, Agassiz Pool, has accumulated so much sediment that it has become dominated by hybrid cattail (Typha × glauca), and the ability of the staff to control water levels in the Agassiz Pool has been substantially reduced. This project consisted of a workshop with Refuge staff, local and regional stakeholders, and several technical and scientific experts. At the workshop we established Refuge management and stakeholder objectives, a range of possible management strategies, and assessed the consequences of those strategies. After deliberating a range of actions, the staff chose to consider the following three strategies: (1) an inexpensive strategy, which largely focused on using outreach to reduce external sediment inputs to the Refuge; (2) the most expensive option, which built on the first option and relied on additional infrastructure changes to the Refuge to increase management capacity; and (3) a strategy that was less expensive than strategy 2 and relied mostly on existing infrastructure to improve management capacity. Despite the fact that our assessments were qualitative, Refuge staff decided they had enough information to select the third strategy. Following our qualitative assessment, we discussed additional considerations and uncertainties that might affect implementation of this strategy.
First posted September 12, 2014
For additional information contact:
Part or all of this report is presented in Portable Document Format (PDF). For best results viewing and printing PDF documents, it is recommended that you download the documents to your computer and open them with Adobe Reader. PDF documents opened from your browser may not display or print as intended. Download the latest version of Adobe Reader, free of charge. More information about viewing, downloading, and printing report files can be found here.
Post van der Burg, Max, Jenni, K.E., Nieman, T.L., Eash, J.D., and Knutsen, G.A., 2014, Decision analysis of mitigation and remediation of sedimentation within large wetland systems—A case study using Agassiz National Wildlife Refuge: U.S. Geological Survey Open-File Report 2014–1180, 24 p., https://dx.doi.org/10.3133/ofr20141180.
ISSN 2331–1258 (online)
Case Study—Agassiz National Wildlife Refuge
Alternative Actions and Strategies
Selection of Preferred Alternative
Appendix I. Qualitative Consequences Table