Floating Sensor Networks for River Studies

Free-floating sensor packages that take local measurements and track flows in water systems, known as drifters, are a standard tool in oceanography, but are new to estuarial and riverine studies. A system based on drifters for making estimates on a hydrodynamic system requires the drifters themselves, a communication network, and a method for integrating the gathered data into an estimate of the state of the hydrodynamics. This paper presents a complete drifter system and documents a pilot experiment in a controlled channel. The utility of the system for making measurements in unknown environments is highlighted by a combined parameter estimation and data assimilation algorithm using an extended Kalman filter. The performance of the system is illustrated with field data collected at the Hydraulic Engineering Research Unit, Stillwater, OK.