The City Council tonight will decide whether water will cascade, stream or fall into small pools outside the community center. The center, expected to cost $22 million, is being built at Paseo de Valencia and Alicia Parkway. It will include athletic fields, a meeting place and a multimedia center. The project will be completed in 2001, City Clerk Mary A. Carlson said. David Volz, the project’s landscape architect, will present three options to the council: a cascading waterfall, a stream and a more traditional waterfall. The council meets at 7 p.m. in chambers, 25201 Paseo de Alicia, Suite 150.