Low-flow Hydrology in the Nepal Himalaya

Abstract

Nepal Himalaya is facing the crucial problem of increasing water scarcity for irrigation and household consumption in many parts. Stream flow remains very low for 9 months a year from October to June. This paper attempts to examine the relationship between stream flow during the dry season and catchment characteristics and identify the most important variables that control flow during the dry season. The relationship between stream flow and different variables of catchment characteristics was examined using bivariate correlation coefficients and regression models. The results show that the topographically influenced climatic condition is important in the control of low flow at larger scales, whereas human induced changes in land use and land cover are important in areas with similar physical environments at smaller scales. Our study highlights the need for proper management of grazing land in the Middle Mountains of Nepal, which could lead to sustained stream flow during the dry season.