Eco-hydrological Model Of Buha River Based On Macroinvertebrates

China has a large population and uneven distribution of water resource.Large-scale river development and utilization,as well as economic and social development,have led to serious problems,such as insufficient river flow,deterioration of water quality,destruction of habitat of aquatic organisms,and extinction of species.In order to improver the water ecological environment and maintain the sustainable development of the ecosystem,the task of water ecological environment restoration is arduous.Understanding the ecological and hydrological law of rivers is the basis for river ecological protection and restoration.This study samples macroinvertebrates and investigates the habitat physical conditions of the Buha River and Giermeng River that is the tributary of Buha River.The eco-hydrological model including hydrological module,hydrodynamic and sediment calculation module is used to simulate the distribution of macroinvertebrates in the Buha River Basin.The main contents of this paper are as follows:(1)Based on the macroinvertebrate data,the distribution patterns in the longitudinal direction of the river is analyzed.From the upstream to the estuary,the species numbers,density and biomass first increase and then decrease and increase finally.The species numbers usually reach a maximum in the middle reaches,and the maximum value of density and biomass are in the middle of river of estuary.(2)The community structure of macroinvertebrates in the Buha River Basin is significantly affected by the seasons.Due to the melting of frozen soil in spring,a large amount of organic particles are introduced into river,making the density and biomass of macroinvertebrate much large than in summer.In addition,the low water temperature in spring makes only some species that could bear cold water environment can alive,such as Gammarus.In summer,the temperature rises and a large number of chironomidae larvae grow and multiply.(3)Substrate,velocity and water depth are the most significant environmental factors for macroinvertebrates.The slow-flow pool of particles or silt sediments are mostly oligochaetes and mollusks.In high-flow riffles area with gravels,aquatic insects with strong anti-scouring ability are more abundant.Chironomidae larvae in low-flow gravel areas are more common.(4)Utilizing the constructed eco-hydrological model to simulated the macroinvertebrates distribution.The results show that the high-flow species are mostly distributed in high-altitude mountainous areas.In addition,increased summer precipitation causes the transition of macroinvertebrate communities from slow-flowing species to common species or high-flow.