Development of a Distributed Rainfall-runoff Model Incorporated with Tank Models for Several Land Utilizations and Quantitative Evaluation of Runoff Change Induced by Rural Development and Climate Change

Abstract

This study aimed to develop a distributed rainfall-runoff model, which simultaneously overcomes the problems of the calculation time and the data scarcity in Southeast Asian watershed to quantitatively evaluate the future changes in rainfall-runoff processes under rural development and climate change. The distributed rainfall-runoff model representing a watershed as a square mesh aggregate was developed. The calculation time was reduced by scaling the mesh resolution in kilometers. Four tank models representing flow characteristics of paddy, upland field, urban and forest areas were incorporated into each mesh element of the distributed rainfall-runoff model to capture the runoff from different land utilizations. A watershed groundwater tank model covering the entire watershed was incorporated to represent the temporally stable base-flow component. Based on scenario analyses, future changes in rainfall-runoff processes with land use and rainfall changes were quantitatively evaluated not only using annual and peak runoff from the entire watershed but also changes in annual runoff and runoff patterns from each land utilization.