Analysis of the Water-saving Effects of the Volumetric Irrigation Water Charge System

— The case of the Mie irrigation scheme —

Abstract

Resource-saving has become a global issue in the 21^st century. This study examined the Mie irrigation scheme and analyzed the water-saving effects of its volumetric water charge system which is generally expected to save water used for rice field irrigation. The results showed that 1) the system saved water by reducing the required diversion volume from the water source in the periods with average river water level; and 2) the volume of water usage markedly increased in the periods of low water when the water saving effects of the volumetric water charge system was most anticipated. For the latter phenomenon, following reasons can be given; 1) some features of the fee structure, such as basic rate, low excess charge and long calculation period of one year, and in addition to that, 2) the supplemental function of the Mie irrigation scheme.