While mean waterfowl population numbers for 1994 and 1995 have shown significant increases, long-term downward trends in these populations are attributed mainly to habitat loss. Prior converted cropland (PC), a federally defined agricultural wetland that no longer meets jurisdictional wetland criteria, often exhibits seasonal wetland characteristics and can provide viable wetland waterfowl habitat, particularly during migration and wintering periods. However, PC is not protected by Swampbuster Provisions of the Food Security Act or Section 404 of the Clean Water Act. Urban development threatens PC and its waterfowl habitat in western Washington's Snohomish River Valley.

The goals of this study are to establish that prior converted cropland constitutes a significant amount of area in the valley, that it provides seasonal waterfowl habitat, and finally that it should be afforded some protection under local, state, or federal regulation. The objectives include assimilating Natural Resources Conservation Service (NRCS) wetland determinations within nearly 11,000 acres of the Snohomish River Valley onto a single basemap, identifying early season hydrologic conditions in the study area, quantifying the amount of early season hydrology exhibited by PC, establishing the potential for conversion of PC, and substantiating waterfowl use of PC.

This study indicates that prior converted cropland in the Snohomish River Valley provides waterfowl habitat on a seasonal basis, especially during the wet winter and early spring months. When fields become inundated, many species of waterfowl (and other wildlife associated with wetland habitat) actively use the inundated areas. The land use designation Riverway Agriculture protects a significant portion of PC in the valley from urban development, but PC inside current urban growth boundaries will likely be converted to urban use. Finally, PC provides excellent opportunities for wetland restoration.