Mesh type runoff model by GIS
Ryuzo Yokoyama, Luo Xiao Bo
Department of Computer Science
I wate University
Morioka, I wate , Japan 020
Abstract
A mesh type run-off model (MR model) is proposed. A basin is divided into square meshes with an uniform size. The runoff characteristics of each mesh are described as tank models. Each mesh is related to its adjacent meshes under the flow-down connection and the total meshes form a tree graph under the connection, of which root is the mesh at dam site of the run-off volume. The MR model can directly describe the spatial and temporal variations of precipitation and runoff parameters, which observed /estimated by remotely sensed data and derived from a GIS of the basin .The model is applied to Yuta dam basin located in northern Japan and demonstrated promising results.
Introduction
A mathematical model to describe the relationship between a precipitation and a runoff volume in a basin, a runoff model, is one of the most important topics in the hydrology. Various types of runoff models, e.g. tank model, kinematic wave method, unit diagram method, etc, have been popularly used. The run-off is a complicated process depending upon spatial and temporal factors of precipitation and run-off conditions. The mathematical models of those, those, however, have been described by a lumped parameters systems with limited number of state described by a lumped parameters systems with limited number of state variable due to the restricted observation techniques.
In recent years, however, we have gotten new technologies to describe a run-off model more precisely as follows.
- Remote Sensing: Land cover/ use, snow-covered
area, topography, clod distribution can be detected from earth
observation satellite.
- Hydrological telemetering system: Various
observation techniques for spatial distribution of rain such as rain
telemetering systems on the ground and train radar systems have been
developed.
- Geographic information system: various
geographic information systems have been developed. By applying the
techniques, the run- off models are conveniently developed.
- Advanced computer system: The computer technology has been developed remarkably in recent years. A rather large scale computation of a detail runoff model can be handled by modern computer systems.
In this paper, a new run-off model called the MR model, which can describe the spatial and temporal run-off characteristics of a basin directly is proposed . After the general statement about the model, a practical model was implemented to Yuta dam basin located in northern Japan. The result of the simulation by using the past observation data at the dam demonstrated a promising results of the model.
