Study On The Habitat Reclamation Of The Four Major Chinese Carps In The Luoqi Channel For The Upstream Of The Yangtze River

The 4.5 m channel regulation project from Chaotianmen to Fuling in the upstream of the Yangtze River is a key step to promote the development of the Yangtze River economic belt and build our country into a transport powerhouse.In order to boost the economic development of port and river with fish habitat and balance the contradiction between the channel expansion project and fish habitat,this thesis selected the Luoqi river section of the upstream of the Yangtze River Fish Resource Protection Zone,determined habitat factors and suitability model based on the research results of the habitat of the four major Chinese carps in the upper reaches of the Yangtze River.Combining with the field investigations and the measured data from the hydrological stations in the fluctuating backwater area in the Three Gorges reservoir,and using a two-dimensional hydrodynamic numerical model to calculate changes of water level,water surface slope,flow velocity,and water depth.Then,analysis of the hydrodynamic characteristics and habitat suitability changes of Luoqi river section before and after the 4.5 m channel regulation project from Chaotianmen to Fuling for the identification of habitat reclamation area and programmed design for the four major Chinese carps.Finally,a more excellent habitat reclamation program with the four major Chinese carps using reef bombing waste is proposed.The conclusion of this thesis are as follows:(1)MIKE21,a two-dimensional hydro-dynamic numerical model,was used to calculate and analysis the water flow characteristics in the Luoqi river section for the upstream of the Yangtze River,and verified the reliability of the model.The key habitat factors(water depth and flow velocity)were selected to determine the suitability curve of the four major Chinese carps,and the habitat suitability evaluation model of the four major Chinese habitat was established.(2)Calculated the hydrodynamic process changes in the Luoqi river section on the4.5 m channel regulation project,and the changes of habitat suitability of the four major Chinese carps under different scheduling were analyzed.Therefore,the impact of the channel regulation project on the habitat of the four major fish were discussed.(3)With the suitability index of 0.6 ～ 1 as the suitable habitat for the four major Chinese carps,and 0.4 ～ 0.6 as the close to suitable habitat,habitat reclamation program of the four major Chinese carps were designed to satisfy the navigational standards of 4.5m channel regulation project and the program is making full use of the most of reef-clearing.After calculation and analysis,it is indicated that the best effect and the best economic benefits of the habitat restoration program is the third program(submerged dam elevation is 145 m).(4)Further proposed to use the reef-clearing and waste slag backfilling at the deep pit on the left bank of the Xialuoqi section to restore the bank slope and the submerged dam side beach,so as to increase the use effect of the submerged dam,give full play to the best economic benefits.Therefore,the habitats of the four major Chinese carps and other fishes in the Luoqi river can be improved.