Abstract:
In developing countries, there is high limitation and irregularity in river flow data recording, and a significant
number of hydrologic basins are ungauged. Despite the fact that the estimation of surface and groundwater asset
assumes the measurements as a basic concern in resource management and planning. Understanding baseflow
forms specifically as a piece of the total flow of river basins can be utilized as a demonstrative tool to portray
hydrologic frameworks and turns into a basic issue of water balance contemplates. Hence, this work seeks to
compare baseflow estimates in the Abaya-Chamo Lakes Basin using baseflow separation algorithms (such as
River Analysis Package (RAP), Time Plot (TP) and Kille (K)). The assessments are then utilized to set up and
establish further the associations with multivariate factors (such as climate, geomorphometric, land use cover
and aquifer properties). Indeed, an accessible 16 daily river discharge records were therefore used to estimate
the value of the Baseflow Index (BFI). The estimates from both River Analysis Package and Time Plot algorisms
are more hydrologically plausible and compared well to each other with a linear correlation coefficient of 0.96.
In any case, the graphical Kille method is somehow underestimated the baseflow yield. The estimated value over
whole ranges between 0.29 and 0.62, which suggests about 42% of the long-term total river flow, is a con
tribution of groundwater discharge. Furthermore, this index was gathered with multivariate's to have a con
sistent causal explanations as a descriptor of the hydrological framework, and have a significant positive
coefficient of correlation with slope, elevation, forest land use cover hypsometric integral, rock age and plateau
physiographic sub-section with its prevailing climatic conditions, and while, negative correlation with grassland
use cover and escarpment physiographic sub-section. This study, therefore, explicitly revealed that the evolution
of geomorphological features in the plateau (physiographic subsection with associated elevation, hypsometric
integral, drainage density, and climatic features were found to be the dominant control of the baseflow yield
over other multivariate's (such as land cover and aquifer properties). The stepwise regression equation for lakes
basin based on multivariate attributes is used as proxy knowledge to ungauged basins to estimate baseflow yield
with considerable caution because of the heterogeneity in various variables.
