Bethel Island levee rules & regulations

Hi all. I recently purchased an old floating home near Frank's Tract & am interesting in finding out information about public access on the levees surrounding Bethel Island. It is my understanding that the top of the levees are open for walking to everyone who lives &/or rents on the island (& guests). I am confused, however, by rules & regulations governing the banks & levee waters along the banks. Do property owners have exclusive rights to the banks & water area across the levee from their property?
Recently I was sitting on some grass on the levee banks by the water near where I rent my houseboat. A neighboring property owner complained that I was sitting on his rocks with my feet in his property's water.
I would really appreciate if someone could give me information on the property rights information regarding these levee areas. Thank you!