Lots of warm rain and a melting snowpack may have contributed to the recent disastrous flooding in California, but the problem boils down to an overdependence upon levees, says UC Davis geology department chair Jeffrey Mount. "Our historic approach to rivers has been to separate them from their floodplains, leading to tragic, but predictable consequences," he says. Author of "California Rivers and Streams: The Conflict Between Fluvial Process and Land Use" (UC Press, 1995), Mount says the levees performed about as well as could or should be expected. Only about one-fifth of the Central Valley levees are engineered by public agencies to adequately control huge amounts of water. The rest are privately constructed levees originally designed to protect agricultural land, whose soils are actually greatly enriched by flooding, he says. "As long as we continue to develop the floodplains of the Central Valley and depend upon levees for our protection, then the events of last week are certain to reoccur," Mount says. He proposes more scientifically based public policies, such as changes in land use and zoning laws to limit further development of flood plains; possible relocation of perennially flooded towns or homes; setting back or removal of some levees; and increased, deliberate use of lands for flood storage.