Ecological barrier constructing of steep slope reservoir bank in the water source of Middle Route of South-to-North Water Diversion Project
WANG Chao1,, ZHANG Hong2,3, LEI Junshan1, JIA Haiyan1, LEI Pei4, YIN Wei1,, 1.Changjiang Water Resources Protection Institute, Wuhan 430051, China 2.State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 3.University of Chinese Academy of Sciences, Beijing 100049, China 4.State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China
Abstract:The bank of the steep bank in Danjiangkou reservoir is zigzag and the gully is deep, and the water-level-flucutation zone is faced with vegetation extinction and ecological degradation after the dam was raised. Restoration of vegetation in water-level-flucutation zone, interception of gully runoff and enhancement of reservoir bay purification capacity are basic ways to construct ecological barrier of reservoir bank. Different community types should be configured according to the time of flooding for vegetation restoration in the water-level-flucutation zone, of which the mixed community of arbor, shrub and herbaceous plants were constructed at the high location (165~170 m), the mixed community of shrub and herbaceous plants were constructed at the middle location (163.5~165 m), and the herbaceous plants were constructed at the low location (160~163.5 m). The purpose of gully runoff interception and block is to reduce erosion, and the main technical measures include ecological interception dam, ecological gully and micro-terrain reconstruction. Water was lifted by windmill to enhance water flow in reservoir bay, and purification measures such as ecological pond were also taken to reflux the extracted water back to reservoir bay after purification, so as to prevent and control eutrophication risk. The technical implementation includes basic data collection, site investigation, problem analysis, engineering measure layout, engineering design and operation monitoring. The application practice case in Yangshan reservoir bank indicated that the removal rates of TSS, total nitrogen, and total phosphorus were greater than 90.4%, 46.8% and 55.3%, respectively. And their outputs were reduced by 112 t·a?1, 19 kg·a?1 and 11 kg·a?1, respectively. This study provides a basis for the ecological barrier construction in the middle route of the south-to-north water diversion project, and also provides reference for the ecological construction of other reservoirs in China. Key words:Middle Route of South-to-North Water Diversion Project/ Danjiangkou Reservoir/ water source/ steep slope/ ecological barrier/ water-level-flucutation zone.
图1丹江口水库位置和库岸类型分布 Figure1.Location and bank type distribution of Danjiangkou Reservoir
PUSEY B J, ARTHINGTON A H. Importance of the riparian zone to the conservation and management of freshwater fish: A review[J]. Marine and freshwater Research, 2003, 54(1): 1-16. doi: 10.1071/MF02041
1.Changjiang Water Resources Protection Institute, Wuhan 430051, China 2.State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China 3.University of Chinese Academy of Sciences, Beijing 100049, China 4.State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210046, China Received Date: 2020-02-29 Accepted Date: 2020-07-06 Available Online: 2020-12-08 Keywords:Middle Route of South-to-North Water Diversion Project/ Danjiangkou Reservoir/ water source/ steep slope/ ecological barrier/ water-level-flucutation zone Abstract:The bank of the steep bank in Danjiangkou reservoir is zigzag and the gully is deep, and the water-level-flucutation zone is faced with vegetation extinction and ecological degradation after the dam was raised. Restoration of vegetation in water-level-flucutation zone, interception of gully runoff and enhancement of reservoir bay purification capacity are basic ways to construct ecological barrier of reservoir bank. Different community types should be configured according to the time of flooding for vegetation restoration in the water-level-flucutation zone, of which the mixed community of arbor, shrub and herbaceous plants were constructed at the high location (165~170 m), the mixed community of shrub and herbaceous plants were constructed at the middle location (163.5~165 m), and the herbaceous plants were constructed at the low location (160~163.5 m). The purpose of gully runoff interception and block is to reduce erosion, and the main technical measures include ecological interception dam, ecological gully and micro-terrain reconstruction. Water was lifted by windmill to enhance water flow in reservoir bay, and purification measures such as ecological pond were also taken to reflux the extracted water back to reservoir bay after purification, so as to prevent and control eutrophication risk. The technical implementation includes basic data collection, site investigation, problem analysis, engineering measure layout, engineering design and operation monitoring. The application practice case in Yangshan reservoir bank indicated that the removal rates of TSS, total nitrogen, and total phosphorus were greater than 90.4%, 46.8% and 55.3%, respectively. And their outputs were reduced by 112 t·a?1, 19 kg·a?1 and 11 kg·a?1, respectively. This study provides a basis for the ecological barrier construction in the middle route of the south-to-north water diversion project, and also provides reference for the ecological construction of other reservoirs in China.
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