The wetlands themselves are divided into three distinct zones, following the divisions already established by the railroad and the freeway. The inner zone east of the freeway already the richest, most diverse habitat becomes a wildlife preserve. The zone between the freeway and the railroad where the water is deeper and wildlife far less abundant will be devoted to biotic production and research. Areas in both natural, or protective, and productive landscape are thus taunt parts of the plan. The productive area is largely a manmade landscape, but one that is biologically very much alive. Some dredging and shoreline alteration may be needed here to develop the best environment for raising fish and mollusks. The old sewage treatment plant on the lagoon's edge will be refurbished as a biological treatment facility to provide an inflow of fresh water.