Remote Sensing Analysis And Experimental Study Of Plant Hydrolysis In Reservoir Riparian Zone

The water level of the water source reservoir is changed due to flood season,and a large area of falling zone is formed around the reservoir.As a connecting zone between land and water,falling zone is an important way to exchange matter and energy between them,and is a key link in the nutrient cycle of ecosystem.The quality of reservoir and land ecological condition is directly affected by the ecological situation of falling zone [1].Among them,the influence of nutrient elements released to reservoir by hydrolysis of vegetation in large area falling zone on water environment can not be ignored.Taking Biliuhe Reservoir as the research object,combining with the OLI data of Landsat-8 satellite images before and after summer flood season,this paper studies the evolution process and environment evolution of Biliuhe Reservoir by remote sensing,and establishes the water quality inversion model for Biliuhe Reservoir,which is suitable for the northern water source reservoir,and analyzes its spatial and temporal distribution characteristics.The release process and its effect on water environment were investigated by simulated hydrolysis experiment of vegetation in the falling zone,and the calculation model of the release of the nutrient elements in the falling zone was put forward.The results are as follows:(1)After the construction of the Biliuhe Reservoir,the falling zone will experience periodic inundation and outcrop every year,and some places will be flooded for six months,during which time the water level of more than 10 m falls.During the past years,the average area of the submerged-exposed caving zone is about 18.07 km2;and the vegetation cover of the unsubmerged zone after the flood season of 2015-2018 is obviously higher than that before the flood season.(2)After the hydrolysis of plant flooding,the color of the surface water will gradually deepen,the turbidity will increase,the odour will be produced,the leaf will gradually transparent,the pH value will decrease,the conductivity will increase,the dissolved oxygen DO will decrease,and the redox potential will ORP decrease.TN maximum cumulative release per unit is 1.34-3.09 mg/g,release rate is 0.04-0.21 mg/g/d;TP maximum cumulative release per unit is 0.52-2.9 mg/g,release rate is 0.02-0.14 After soaking and hydrolyzing,nitrogen and phosphorus elements were released to the surface water.(3)Compared with the total nitrogen concentration before the summer flood season,the total nitrogen concentration in the Biliuhe reservoir increased by about 62%.The average annual release of total nitrogen t,total phosphorus is about 7.78 t.in 4 years...