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Identification of the main attribute of river flow temporal variations in the Nile Basin

Journal Contribution - Journal Article

Temporal variation of monthly flows was investigated at 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–runo 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 dier 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 influencein the Nile basin over the selected time period was minimal. Thus, the overall rainfall–runo 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.
Journal: Hydrology and Earth System Sciences
ISSN: 1027-5606
Volume: 12
Pages: 12167-12214
Publication year:2015
Keywords:river flow, Nile basin