Abstract:

Delayed response is one of important characteristics of self-adjustment in fluvial processes. Based on the mechanism of delayed response in fluvial processes, a delayed response model, considering the effects of water-sediment regime and the base level (Tongguan elevation), was developed to simulate the sedimentation processes in wet and dry seasons. The measured data in the period of 1960-2001 was used to estimate the parameters, and the measured data in the period of 2002-2015 was used to validate this model. Results showed that the proposed model could reasonably simulate the sedimentation processes in wet and dry seasons in the Xiaobeiganliu reach. This model performed better for cumulative sediment storage than single sediment storage in wet and dry seasons. Besides, this model also performed better for cumulative and single sediment storage in wet season than in dry season. Since the closure of Sanmenxia Dam, the sedimentation processes in wet and dry seasons in the Xiaobeiganliu has changed obviously in different periods during 1960-2015. Using this model, the contributions of water-sediment regime and the Tongguan elevation on sedimentation in different periods were analyzed. The sedimentation process was mainly affected by the Tongguan elevation in the period of 1960-1970(wet season) and 1960-1968(dry season). However, it was dominated by water- sediment regime after 1970(wet season) and 1968(dry season).

Key words: Xiaobeiganliu reach, silt and scour, Tongguan elevation, delayed response model, wet and dry seasons