LAGRANGIAN MONITORING OF RIVER FLOW WITH GPS FLOATS

Abstract

We attempted to conduct a Lagrangian monitoring of river flow by using a number of floats with GPS sensor which can track its position with the accuracy less than 5m. The field measurements with the GPS floats were carried out in the middle reach of the Edo River in low-flow conditions. The observed results show that the GPS floats may track the Lagrangian behavior of river water and easily obtain the horizontal patterns of river flow. The dispersion of river flow evaluated from the GPS floats indicates that the dispersion coefficients for materials in surface layer are found to be positive and negative. The same phenomenon of the dispersion is also confirmed through the 3D river-flow simulation.