The period for the public to comment on a proposed expansion of Graton Resort and Casino ends today. The Federated Indians of Graton Rancheria notified Rohnert Park of the expansion plans last month. They want to build a second hotel tower and expand the gaming floor. The public has until 5 p.m. today to mail comments such as possible environmental issues and mitigation proposals to the reservation’s office. Comments can also be emailed to Sonoma County.