Nisqually Delta Restorations: Design, Monitoring and Evaluation

For the first time in over 100 years, tidal flow was restored to 308 hectares of the Nisqually National Wildlife Refuge (Refuge) in the Fall of 2009.  Over 11 km of dikes and levees were removed, reconnecting nearly 34 km of historic tidal channels and sloughs. Along with 57 hectares of previously restored wetlands by the Nisqually Indian Tribe (Tribe), the Nisqually Delta represents the largest estuarine restoration in the Pacific Northwest to assist in the recovery of Puget Sound salmon and wildlife populations.  The U.S. Geological Survey (Western Ecological Research Center, Pacific Coastal and Marine Science Center, Western Fisheries Research Center, and Washington Water Science Center), along with the Refuge and Tribe are leading efforts to monitor and evaluate the effects of the restoration within an adaptive management framework.  Through partnerships, coordination, and collaborations, we present our initial monitoring results of a landscape transitioning back to a tidal marsh ecosystem.  We tracked the restoration of hydrodynamic processes that drive geomorphic change within the reconnected tidal channels. These results are being linked to biological responses of the fish, birds, invertebrates, and vegetation.  We also highlight an early example of the adaptive management cycle: detection of channel constriction and poor drainage through observation and monitoring, the subsequent assessment and decision to take corrective action, the design and implementation of deepening the channel, and the resulting improved habitat connectivity and water quality for wildlife.