IMPERIAL BEACH — The U.S. Section of the International Boundary and Water Commission will hold a public forum from 6:30 to 8:30 p.m. Thursday in Imperial Beach. Agency officials plan to discuss coastal water monitoring and other programs in the South Bay. There will be time for public comment. The commission is expanding its wastewater treatment plant in San Ysidro to better process sewage coming from Tijuana. That project is supposed to be done in January 2011. The meeting will take place at the Imperial Beach community room, 825 Imperial Beach Blvd.