Identification of the main attribute of river flow temporal variations in the Nile Basin
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Date
2015
Authors
Journal Title
Journal ISSN
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Publisher
Hydrology and Earth System Sciences Discussions
Abstract
Temporal variation of monthly flows was investigated at 18 Discharge Measurement
Stations (DMS) within the Nile Basin in Africa. The DMS were grouped using a clustering
procedure based on the similarity in the flow variation patterns. The co-variation of
the rainfall and flow was assessed in each group. To investigate the possible change
in catchment behavior, which may interfere with the flow–rainfall relationship, three
rainfall–runof models were applied to the major catchment in each group based on
the data time period falling within 1940–2003. The co-occurrence of the changes in the
observed and simulated overland flow was examined using the cumulative rank differ
ence (CRD) technique and the quantile perturbation method (QPM). Two groups of the
DMS were obtained. Group 1 comprises the DMS from the equatorial region and/or
South Sudan, while those in Sudan, Ethiopia and Egypt form group 2. In the selected
catchment of each group, the patterns of changes in terms of the CRD sub-trends and
QPM anomalies for both the observed and simulated flows were in a close agreement.
These results indicate that change in catchment behavior due to anthropogenic influence
in the Nile basin over the selected time period was minimal. Thus, the overall
rainfall–runoff generation processes of the catchments were not impacted upon in a
significant way. The temporal flow variations could be attributed mainly to the rainfall
variations.
Description
Keywords
River flow, Nile Basin
Citation
Onyutha, C., & Willems, P. (2015). Identification of the main attribute of river flow temporal variations in the Nile Basin. Hydrology and Earth System Sciences Discussions, 12(11), 12167-12214. doi:10.5194/hessd-12-12167-2015