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| Variation in the rainfall-runoff-sediment delivery relationships of Lu’ergou Watershed in the hilly-gully region on the Loess Plateau |
| (1.College of Water Resources and Civil Engineering, China Agricultural University, 100083, Beijing, China; 2.Beijing Grandtopeak Tianpinghang Land Plan and Design Co., Ltd. , 100873, Beijing, China; 3.State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, CAS and MWR, 712100, Yangling, Shaanxi, China; 4.Tianshui Soil and Water Conservation Station, Yellow River Conservation Commission, 741000, Tianshui, Gansu, China) |
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Abstract Rainfall-runoff-sedimentation relationships are of great importance for predicting watershed soil erosion and evaluating the benefits of soil and water conservation in the watersheds. The hydrological data of 74 flood events of Luergou Watershed on the Loess Plateau from 1982 to 2010 were used to investigate the relationships among rainfall, runoff and suspended sediment transport. The variations of event-based runoff coefficients and mean suspended sediment concentrations and their significance were identified using the Mann-Kendall test method. The results indicated that the precipitation and duration of rainfall event were the most relevant factors controlling the hydrological response. The most significant correlation was observed between runoff coefficient and 7-day antecedent precipitation. Sediment yield was closely related to runoff in Luergou Watershed. The jump point for the sequence of the event-based runoff coefficient was the flood event on 24 August 1985. Afterwards, there was a significant decreasing trend in the sequence of event-based runoff coefficient. The increase in the vegetation cover area in Lu’ergou Watershed was the main cause for the change of the rainfall-runoff relationship. There was no significant change for the sequence of event-based mean suspended sediment concentration, which indicated that the soil and water conservation based on vegetation measures had no significant effect on the runoff-sedimentation relationship of Lu’ergou Watershed.
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Received: 22 February 2013
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