Runoff Simulation Of Longxi River Basin Based On Arc SWAT Model

Human activities and climate change are gradually intensifying,leading to great changes in the hydrological cycle of the basin,resulting in a decrease in river water volume,serious soil erosion,and deterioration of water ecology.In order to study the impact of human activities on the basin,this paper selects the Longxi River in Chongqing.The basin is the study area.Based on the measured meteorological data,rainfall data,soil type,land use and other data in the basin,the integrated reservoir,supply and water data,and the impact of various human activities on the flow and convergence.By constructing the SWAT distributed hydrological model,the runoff process of the basin was analyzed and verified.Then,according to the construction of Longxi River water conservancy project,the SWAT simulation results were used as the verification standard to establish the ecological scheduling model of Longxi River Basin.The main conclusions are as follows.The SWAT model of the Longxi River Basin was established.After the parameter rate was determined,the Nash-Suttcliffe of the monthly runoff simulation calibration period was 0.76,and the RE was-2.9%.The Nash-Suttcliffe of the monthly runoff simulation verification period is 0.70 with a RE of 8.5%.The runoff simulation results show that the SWAT model is more accurate for the simulation of the basin,indicating that the model is suitable for long-term simulation of the basin.In order to analyze and compare the ecological dispatching effect of Longxi River,it is necessary to review the dispatching of reservoirs in the basin.In this paper,the SWAT simulation results are used to compare the calculated results with the measured runoff of Liujiantan hydrological station with a deterministic coefficient of 0.77.According to the calculation results of the study scheduling model,the Pingtan warehousing flow is compared with the measured runoff of Liujiantan,and the deterministic coefficient reaches 0.85.The description has a very good effect.In the calculation process of the ecological water demand of Longxi River,the pollution capacity of the downstream river channel is not considered,and three ecological water demand schemes are set here.Calculating different schemes and comparing the scheduling results,we can find that because the power generation flow can be used as the ecological flow,as the ecological water demand increases,in order to meet the ecological water demand,the model increases the power generation amount and increases the discharge flow to achieve purpose.Therefore,the calculation results show that as the ecological flow increases,the amount of power generation continues to increase.In order to meet the water consumption of the living industry and agriculture,when the reservoir falls to the dead water level,the ecological water demand is not met,and as the ecological water demand increases,the number of times the reservoir falls to the dead water level increases,and the ecological water shortage increases.Ecological flow and agriculture have strong competition,and agricultural water supply and domestic industrial water supply continue to decrease with the increase of ecological water demand.The degree of impact is inversely related to the size of the reservoir.Due to the poor regulation ability of the small reservoir,the water recovery capacity is weak after the ecological flow is increased,and the agricultural and domestic water supply is easily destroyed in the later period.Since the power generation flow can be used as the ecological flow rate,as the ecological water demand increases,in order to meet the ecological water demand,the model increases the power generation amount and increases the discharge flow to achieve the goal.