嘉陵江亭子口枢纽变动回水区通航流量及保证率分析

Analysis of navigable discharge and guarantee rate in fluctuating backwater area of the Jialing River Tingzikou project

按照《四川省内河航运发展规划》,嘉陵江川境内规划14个梯级,2030年实现广元—昭化段达到Ⅳ级航道标准的目标,但是由于《长江流域综合规划》取消了嘉陵江水东坝枢纽,造成亭子口与上石盘枢纽之间水位不能衔接。亭子口电站设计水位变幅高达20m,导致库尾存在长约28km的变动回水区,而该段航道天然来流量很小,仅通过航道整治不能达到规划的Ⅳ级航道标准。因此采用优良河段河相关系法,将整治后的滩险河床断面形态与优良河段建立特征流量下的河相关系,推求不同流量下整治滩险可能达到的稳定航深,从而找到工程河段满足Ⅳ级航道水深标准的最小流量。再根据水文站资料分析此流量出现的时间,结合亭子口电站特征水位回水里程,分航段研究通航保证率,提出亭子口库尾变动回水区达到规划的Ⅳ级航道的流量和保证率。

According to the Inland river navigation development plan of Sichuan Province,there are 14 steps planned in the Jialing River,and the section from Guangyuan to Zhaohua will reach the Grade Ⅳ waterway standard by 2030.However,due to the Comprehensive planning for the Yangtze River basin,the Shuidong dam junction of the Jialing River was cancelled,the water level between Tingzikou and Shangshipan junction cannot be connected.The designed water level variation range of Tingzikou hydropower station is as high as 20 m,which results in a fluctuating backwater area of about 28 km at the end of the reservoir.The natural flow of this waterway section is very small,and the planned grade Ⅳ waterway cannot be achieved only through waterway regulation.Therefore,this paper adopts the method of good river section correlation to establish the river correlation under the characteristic flow between the beach dangerous riverbed after regulation section shape and the good river section,and infer the stable navigation depth that may be achieved by the beach dangerous riverbed regulation under different flows,so as to find the minimum flow of the engineering reach that meets the water depth standard of ClassⅣ channel.Then the paper analyzes the time of occurrence of this flow based on the data from the hydrological station,combined with the characteristic water level backwater mileage of the Tingzikou Power Station,studies the navigation guarantee rate by segment,and proposes the flow rate and guarantee rate for the variable backwater area at the rear of the Tingzikou Reservoir to reach the planned level Ⅳ channel.