Causes of high water losses from irrigated rice fields: field measurements and results from analogue and digital models

Abstract

In places where rice is grown in paddy fields with permanent bunds, considerable quantities of water are lost through lateral seepage of water into the bund and from there vertically to the groundwater. Lateral percolation losses increase with increases in field water depth, bund width, aquifer thickness and depth to groundwater. These losses do not occur in systems where the bunds are reformed every year. The paper discusses the areas of research required to quantify the magnitude of these `losses' at a scheme level and suggests management interventions to improve the efficiency of water use.