California’s littoral cells were originally digitized by Melanie Coyne from the Assessment and Atlas of Shoreline Erosion Along the California Coast (Habel, J. S. and G. A. Armstrong, 1978). Cells were revised in 2005 by Kiki Patsch to refine certain cells and add sediment budget information. The coastline of California can be divided into a set of distinct, essentially self-contained littoral cells or beach compartments. These compartments are geographically limited and consist of a series of sand sources (such as rivers, streams and eroding coastal bluffs) that provide sand to the shoreline; sand sinks (such as coastal dunes and submarine canyons) where sand is lost from the shoreline; and longshore transport or littoral drift that moves sand along the shoreline. Sediment within each cell includes the sand on the exposed or dry beach as well as the finer-grained sediment that lies just offshore.