Abstract
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.
Highlights
IntroductionThe stream flow response to rainfall depends on the catchment attributes [1] that include the physiographic, underlying geology, vegetation cover and rainfall amount, intensity, and frequency
The stream flow response to rainfall depends on the catchment attributes [1] that include the physiographic, underlying geology, vegetation cover and rainfall amount, intensity, and frequency.The interaction between these attributes and the nature of the response are variable in space and time and induce complexity which cannot yet be predicted in hydrology [2]
Grouping of gauging stations into flow regime classes based on time series data and selected hydrological variables has shown some significance in large-scale river management and research [7,18] for environmental monitoring, simplifying water allocation decisions and environmental flow setting [1,18,19], and used as a tool for comparative hydrology to understand the physical representations of the flow duration curves [20,21,22,23,24]
Summary
The stream flow response to rainfall depends on the catchment attributes [1] that include the physiographic, underlying geology, vegetation cover and rainfall amount, intensity, and frequency The interaction between these attributes and the nature of the response are variable in space and time and induce complexity which cannot yet be predicted in hydrology [2]. Grouping of gauging stations into flow regime classes based on time series data and selected hydrological variables has shown some significance in large-scale river management and research [7,18] for environmental monitoring, simplifying water allocation decisions and environmental flow setting [1,18,19], and used as a tool for comparative hydrology to understand the physical representations of the flow duration curves [20,21,22,23,24]. Temporal flow data have been combined with spatial environmental and physical data of watersheds in statistical classifications that were used to predict river flow regimes for ungauged watersheds [1,19]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
