嘉陵江不同区域场次洪水输沙规律

对于雨洪河流,河流年输沙量主要来源于1场或几场高强度暴雨洪水过程,开展流域次洪输沙规律研究对认识流域水沙变化特性、提升流域产输沙的预测能力具有重要意义。利用嘉陵江流域小河坝站、罗渡溪站、武胜站及北碚站的历年场次洪量与输沙量资料,基于径流侵蚀功率理论和M-K分析等方法,系统分析了嘉陵江不同区域的次洪输沙特性。结果表明：嘉陵江流域汛期洪量和输沙量主要来自于嘉陵江干流;嘉陵江不同区域场次洪量均呈不显著减少趋势,次洪输沙模数(输沙量)总体呈显著减少趋势,但小河坝站2013—2020年次洪输沙模数(输沙量)呈显著增加趋势;随着径流侵蚀功率的逐渐增加,各区域不同时段的次洪输沙模数(输沙量)的变幅逐渐减小;嘉陵江干流区武胜站场次洪水输沙过程受人类活动影响最大、渠江罗渡溪站次之、涪江小河坝站最小;受汶川地震及强降雨等影响,小河坝站和北碚站2013—2020年次洪输沙量较1999—2012年有一定程度增加,但北碚站增幅小于小河坝站。

Study on sediment transport law of flood event in different areas of the Jialingjiang River basin

For rivers flooded by rain, the annual sediment load is mainly derived from one or several rainstorms in the flood season and is of research significance. Based on the theory of runoff erosion power, the M-K method and the daily measured runoff and sediment data for the Xiaoheba, Luoduxi, Wusheng and Beibei stations in the Jialingjiang River basin, this paper analyzed the sediment transport characteristics during flood events in different periods and regions. The results of this paper are as follows: the runoff and sediment discharge during the flood season mainly came from the main stream of the Jialingjiang River. In general, the runoff discharge of flood events in different regions showed no significant decreasing trend, while the sediment transport modulus(sediment load) showed a significant decreasing trend except at Xiaoheba station in 2013—2020. With the gradual increase in runoff erosion power, the variation ranges of the sediment transport modulus(sediment load) in different periods in the Jialingjiang River basin were correspondingly narrowed. The degrees of influence of human activities on the sediment transport processes were weakened in the order of the Wusheng station in mainstream Jialingjiang River, Luoduxi station in Qujiang River and Xiaoheba station in Fujiang River. Affected by the Wenchuan earthquake and rainstorms, the average sediment loads in flood event of the Xiaoheba and Beibei stations in 2013—2020 were higher than those in 1998—2012,while the rate of increase rate at the Beibei station was less than that of the Xiaoheba station.