The McCormack-Williamson Tract is a North Delta island located immediately downstream of the confluence of the Cosumnes and Mokelumne Rivers.

Owned by The Nature Conservancy California, the island offers opportunities for restoration of of critical tidal freshwater marsh and floodplain habitat. There is also the potential that the island could be managed in such a way as to moderate flood flows in the North Delta.

In 2000, the Watershed Center began the research and baseline studies necessary to inform restoration planning and design, and the monitoring of restoration success.

This study included analysis of historic geomorphic conditions, characterization of the modern hydrologic and sedimentologic regime, and baseline studies of aquatic and riparian resources.