The above video was posted one day prior to a major, much-publicized experiment, tracing water movement in California’s Sacramento-San Joaquin river delta, which is prone to reversals in the direction of flow. A more polished video produced on the occasion of the launch of 100 floating sensors into that river system appears below. The Floating Sensor Network is a project of the University of California at Berkeley, involving the Lagrangian Sensor Systems Laboratory (LSSL), the Lawrence Berkeley National Laboratories (LBNL), and the California Department of Water Resources.