Research On The Ecological Flow Of The Main Stream Of The Hulan River At TieLi Based On The River2D Model

The process of urbanization is accelerating,and the scope of human activities is also expanding,resulting in the deterioration of water ecosystems in many river systems in my country and the problems of over-exploitation and utilization of water resources.Domestic research on the ecological flow of river systems has not yet formed a complete system,and the relationship between aquatic reproduction and habitat activities and hydrological processes has not been paid enough attention.In the river ecosystem,the life process of fish is closely related to the change of river hydrological regime,so it is very suitable as an indicative species for the formulation of river ecological flow targets.The use of indicator species to study the ecological flow of the main stream of the Hulan River can provide help for the ecological environment protection and sustainable utilization of water resources in Heilongjiang Province and even the entire Songhua River system.This paper uses 2D River model to simulate 2D hydrodynamic model of river reach,the target ecological discharge value of Hulan River main stream was discussed based on the simulation results of fish habitat suitability area.Through the research,it is found that:(1)Compared with the historical monitoring data,the number of fish populations in the main basin of the Hulan River has decreased by 5-7 species,the diversity of fish species has declined,the population richness has been degraded,and the ecological environment of the river has been destroyed;In the restoration of the watershed water ecological environment and the protection of fish habitats,the impact of urbanization and human activities on the river water ecosystem should be reduced as much as possible.(2)Based on the fish population survey data in the main stream of the Hulan River,it was determined that the indicator species for the study of ecological flow in the study section of the main stream of the Hulan River was Channa asiatica.Five different flow conditions were set for the two-dimensional hydrodynamic simulation of the main stream of the Hulan River and the simulation of the area distribution of fish habitat suitability.The outflow and inflow of the five different flow conditions are basically consistent and within the range of 95%Q＿in≤Q＿out≤105%Q＿in,indicating that the model has achieved good convergence and the simulation structure of the model is accurate and reliable.(3)Use the simulation results to draw the Q-WUA curve chart of the suitable area distribution of the habitat under different traffic conditions under different traffic conditions.The numerical analysis of the Q-WUA curve can be found that when the analog flow is 4.95m~3/s,the habitat is suitable The sexual area has reached the maximum value,It shows that the traffic conditions in this range can meet the traffic requirements of Channa asiatica in the habitat of the habitat in the river section.Therefore,the target value of the Hulan River’s dry flow ecological flow target is 4.95m~3/s.However,the hydrological situation of the dry flow of the Hulan River is greatly affected by human activities,and it is impossible to accurately ensure that the river flow is near the target value.Therefore,according to the Q-WUA curve,it is recommended to use 1.65 m~3/s ～ 16.5 m~3/s as the Hulan River dry flowing biology creature.Protection is suitable for ecological flow.