Spatiotemporal variability of hydrological variables of dapo watershed, upper blue Nile basin, Ethiopia

Abstract

This chapter discusses the results of an experimental hydrological study in Dapo watershed located at the head of the upper Blue Nile Basin in Ethiopia. Detailed spatial measurements of rainfall and soil moisture were conducted at five rain gauge stations and fifteen soil moisture stations of varying depths. It was observed that there is relatively higher consistency of rainfall data in four manual rain gauge stations. Spatial and temporal distribution of soil moisture (%) shows uniform pattern of distribution at different sample depths and most of the stations showed high degree of correlation between the station values. However, unlike the soil moisture, the groundwater level at three automatic monitoring stations showed relatively differing pattern of distribution as indicated by the low degree of correlation among station values. Measurements also showed that the baseflow contribution is greater than the direct runoff contribution at the outlet of the watershed indicating streamflow generation in the watershed dominated by subsurface flow.