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Hydrological regime shifts and functional river typologies in South-Western Nigeria | ||
| مدل سازی و مدیریت آب و خاک | ||
| مقالات آماده انتشار، پذیرفته شده، انتشار آنلاین از تاریخ 17 شهریور 1404 | ||
| نوع مقاله: پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22098/mmws.2025.18030.1641 | ||
| نویسندگان | ||
| Ayoola Awode* 1؛ James Adewumi2؛ Obinna Obiora-Okeke3؛ Akinola Komolafe4 | ||
| 1PhD of Department of Civil Engineering, Federal University of Technology, Akure, Nigeria | ||
| 2Professor, Department of Civil Engineering, Federal University of Technology, Akure, Nigeria | ||
| 3Associate Professor, Department of Civil Engineering, Federal University of Technology, Akure, Nigeria | ||
| 4Associate Professor, Department of Remote sensing and Geo-informatics, Federal University of Technology, Akure, Nigeria | ||
| چکیده | ||
| Rivers in tropical regions and specifically West Africa are experiencing core hydrological changes under the twin-impacts of climate variability and intense land use change. This study analysed daily discharge for six rivers in South-Western Nigeria (Oba, Ogbese, Ogun, Osun, Owena, Yewa) over 1983–2023 (~14,600 observations per river). Methods combined Mann–Kendall with Sen’s slope (annual means), flow-duration curves (Q10/Q50/Q90 and log-slope), descriptive statistics, percentile-based extremes (Q95/Q5), Weibull flood-frequency, Colwell’s predictability (P, C, M), and PCA–k-means clustering. No river showed a significant monotonic trend (p > 0.05), yet variability was large (CV range ≈ 1.03–2.10). Ogun carried the largest high flows (Q10 = 488 m³ s⁻¹) and, with Yewa (CV ≈ 1.03), exhibited more baseflow support; Oba and Ogbese were flashy (CV = 2.10 and 1.37). Predictability was low across basins (P ≤ 0.246; C = 0), indicating unstable seasonality. Extremes were frequent: each river recorded ~296–749 flood days and a similar number of drought days over the record; 100-year peaks in Ogun exceeded 3,000 m³ s⁻¹. PCA–k- means separated Ogun from the other five rivers, supporting a functional typology for management. These findings argue for regime-oriented, nonstationary planning: linking operations, urban green infrastructure, and monitoring to variability, thresholds, and detected shifts rather than historical means. | ||
| کلیدواژه‌ها | ||
| South-Western Nigeria؛ streamflow؛ flow-duration curve؛ Mann–Kendall test؛ Colwell predictability؛ hydrological extremes | ||
| مراجع | ||
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آمار تعداد مشاهده مقاله: 18 |
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