松花江流域主要干支流纵向连通性与鱼类生境

基于松花江流域拦河建筑物现状,采用阻隔系数法,评价主要干支流的纵向连通性。结果表明:松花江干流和嫩江纵向连通性指数分别为0.21和0.27,连通性评价等级为良,第二松花江连通性指数为0.62,连通性评价等级为中等。嫩江支流中连通性最好的是嫩江,成为冷水性鱼与嫩江尼尔基以下河段交流的唯一通道;而甘河、雅鲁河、绰尔河和讷谟儿河连通性评价等级为良,洮儿河、霍林河和乌裕尔河连通性评价等级为劣。第二松花江支流中伊通河和饮马河拦河坝众多,鱼类洄游受阻,连通性等级为劣。松花江干流支流牡丹江、拉林河受梯级水电站开发影响,其评价指数为劣;倭肯河、汤旺河受河流沿岸灌区渠首闸坝、水库及水电站建设影响,评价等级为差,这些支流目前濒危珍稀鱼类已绝迹,也极少见到冷水性鱼类。整个流域内未建设过鱼设施,对鱼类洄游和种群交流产生阻隔,提出了补建和新建过鱼设施,必要时开展增殖放流的措施。建议对没有预留生态流量的拦河建筑物进行改造或者利用现有设施泄放生态流量,对预留生态流量的调整水库调度方案保证其下泄流量满足不同时间、空间鱼类生存需求。

Longitudinal connectivity and fish habitat of main tributaries in Songhuajiang River Basin

Based on the current situation of the river blocking structures in the Songhua River basin, the barrier coefficient method is used to evaluate the longitudinal connectivity of the main tributaries. The results show that the longitudinal connectivity indices of the Songhua River and Nenjiang are 0. 21 and 0. 27 respectively, the connectivity grade is good. The connectivity index of the second Songhua River is 0. 62, and the connectivity level is medium. The best connectivity among the Nenjiang tributaries is Nenjiang, which is the only passageway for cold water fish to interflow with the lower reaches of Nierji, Nenjiang. The connectivity of the Gan River, Yalu River, Chuoer River and Nemo River connectivity level is good, and the same of the Taoer River, Huolin River and Wu Yuer River is inferior. Yitong River and Yinma River of the second Songhua River tributary have numerous dams, fish migration is blocked, their connectivity level is inferior. Mudanjiang, Lalin River of Songhua River tributaries are influenced by the development of cascade hydropower stations, their evaluation index is bad; Wukan River, Tangwang River, affected by the construction of dam gates, reservoirs and hydropower stations along the river irrigation area, evaluation grade for them is poor. At present, the endangered rare fish in these tributaries have been extinct, cold water fish are rarely seen. Fish pass structures are not built in the whole basin, which blocks fish migration and population exchange. Such measures as to make up and build fish pass structures and carry out the proliferation and release of fish if necessary are proposed in this paper. The river structures without reserved ecological flow are to be reconstructed or the ecological flow is discharged by using the existing facilities. For those river structures with reserved ecological flow, reservoir regulation scheme shall be adjusted to ensure that the discharged volume will meet fish survival needs at different times and in different spaces.