It may be, depending on the location of your property and whether a study has been completed on that particular reach of the river. Beginning in 2000, and each year since then, ASLD has commissioned intensive studies of the sovereign boundary. Because these studies are expensive and time consuming, the river has been subdivided into 5 reaches, from Davis Dam north of Bullhead City, to the Northern International Boundary between California and Arizona, near Yuma. (The Southern International Boundary is where Arizona dips further south than California, and forms a boundary with Mexico.)
As of this writing, January 2009, three of the five reaches have been field surveyed, and official plat maps of the sovereign boundary location have been printed. Copies of these maps reside at the respective County Recorder’s office, and here at ASLD. Contact ASLD’s Engineering Section to determine if a study has been completed for your area. Providing the Township, Range and Section numbers for your property is helpful, but not necessary.
If your property lies within a reach of the river that has not yet been studied and surveyed, you have the option of hiring a registered land surveyor or riparian boundary expert to perform a sovereign boundary investigation. Those results will have to be reviewed and approved by ASLD.