Comparative Analysis Of Ganjiang River Sink Before And After Regulations Based On Mathematical Models

The Ganjiang river sink is located in the middle north part of Jiangxi province which is the core economic development zone of Jiangxi province.Therefore its navigation,flood control,and irrigation have a significant influence on the economic development of Nanchang City.In recent years,the water ecology and water security of the tail area of Gan River downstream has become more and more serious because of the development of social economy and the acceleration of urbanization.The problem is manifest in the following aspects:(1)the water area has decreased and its connectivity has become poorer;(2)the water exchange and self-purification capacity has weakened and water quality has deteriorated obviously;(3)the water level of Ganjiang River continued to decline during drought period which results in the decrease of water area.At the same time,the water landscape effect has become worse and the use of water is difficult;(4)The ecological functions of rivers and lakes are deteriorating and the trend of deterioration of water environment is obvious,which means the carrying capacity of water resources and water environment is weakening.In order to improve the water ecological environment and the carrying capacity of regional water resources,it is of great significance to renovate Ganjiang River.Also,it is effective in the aspect of reducing the pressure of regional flood control and promote the development of shipping tourism.In order to study the remediation effect of the proposed project in the downstream of Ganjiang River,this article established 2-D water flow and sediment mathematical model by analyzing the variation regularity of water and sediment characteristics.The hydraulic data of 1992,2002 and 2004 was set as typical boundary conditions,which is used to establish the numerical simulation under different conditions.The effects of different regulation schemes on the regulation of Ganjiang River were discussed with complex water control projects.Then,the effect of the proposed project was evaluated by comparing flood and low water level change,shunt ratio change,erosion-deposition variation of channel and bed utilization under different conditions.It is concluded that the NO.1 improvement scheme would be better because it can relieve the flood pressure of tail river channel,increase the water level during drought period,improve the water environment,stabilize the diversion ratio,improve the utilization rate of the beach and promote regional economic development.