Integration of tank and unsteady flow models

摘要

The objective of this study is to develop a model which can analyze both runoff and flow movement in a large basin that includes mountainous, hilly, and low-flat tidal areas. In this paper, we sought some possibilities of developing such an integrated model. First, the tank model by Sugawara and the unsteady flow model based on the Preissmann scheme are outlined as typical runoff and unsteady flow models. Their structures and features are examined, and the tank model is shown to be imitated by theunsteady flow model. In the unsteady flow model, a tank is represented by a wide, shallow channel, and a hole is represented by a set of gate and weir. A hygrograph calculated by the imitated tank model is presented to show that it is essentially identical to that calculated by the tank model. Second. another model for a low and flat paddy field is also presented. In this model, surface and sub-surface of a paddy field are represented by some hydraulic structures, and some imaginary interior boundariesare also proposed, which are essential to describe water movement in an aquifer. As a conclusion, we confirm the feasibility that the unsteady flow model could develop into an integrated model.