Flow Regime Classification and Hydrological Characterization: A Case Study of Ethiopian Rivers

Water

Belete Berhanu¹  Yilma Seleshi¹  Solomon S. Demisse²  Assefa M. Melesse³ 

[1] School of Civil and Environmental Engineering, Addis Ababa Institute of Technology (AAiT), Addis Ababa 385, Ethiopia; E-Mails:;Ethiopian Institute of Water Resources (EIWR), Addis Ababa University, Addis Ababa 3001, Ethiopia; E-Mail:;Department of Earth and Environment, Florida International University, Miami, FL 33199, USA

关键词: Ethiopia;    flow regime;    ephemeral;    intermittent;    perennial;    hydrological indices;    flow duration curve;   

DOI  :  10.3390/w7063149

来源: mdpi

【 摘 要 】

The spatiotemporal variability of a stream flow due to the complex interaction of catchment attributes and rainfall induce complexity in hydrology. Researchers have been trying to address this complexity with a number of approaches; river flow regime is one of them. The flow regime can be quantified by means of hydrological indices characterizing five components: magnitude, frequency, duration, timing, and rate of change of flow. Similarly, this study aimed to understand the flow variability of Ethiopian Rivers using the observed daily flow data from 208 gauging stations in the country. With this process, the Hierarchical Ward Clustering method was implemented to group the streams into three flow regimes (1) ephemeral, (2) intermittent, and (3) perennial. Principal component analysis (PCA) is also applied as the second multivariate analysis tool to identify dominant hydrological indices that cause the variability in the streams. The mean flow per unit catchment area (QmAR) and Base flow index (BFI) show an incremental trend with ephemeral, intermittent and perennial streams. Whereas the number of mean zero flow days ratio (ZFI) and coefficient of variation (CV) show a decreasing trend with ephemeral to perennial flow regimes. Finally, the streams in the three flow regimes were characterized with the mean and standard deviation of the hydrological variables and the shape, slope, and scale of the flow duration curve. Results of this study are the basis for further understanding of the ecohydrological processes of the river basins in Ethiopia.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.