MATHEMATICAL-MODEL FOR RIVER ICE PROCESSES

A computer model RICE is developed for simulating ice processes in rivers. In the river-hydraulics component, the flow condition is determined from one-dimensional unsteady flow equations. In the thermal component, distributions of water temperature and ice concentration are determined from transport equations of thermal energy and ice. Effects of surface ice, skim-ice, and border ice formations on the ice production are considered. The formation of ice cover is formulated according to existing equilibrium ice-jam theories, with consideration to the interaction between the ice cover and the flow. The undercover ice accumulation is formulated according to the critical velocity criteria. The thermal growth and decay of the ice cover is simulated using a finite-difference formulation applicable to composite ice covers consisting of snow, ice, and frazil layers.