| Danjiangkou Reservoir is the source of water for the Middle Route Project of South-to-North Water Transfer.The study of the dynamic changes of water volume is of great significance to guide the management of the water volume of the reservoir.At the same time,since the heightening of the Danjiangkou Dam,a 205km2 fluctuating zone has been added.The fluctuating zone and the reservoir have formed a complex and diverse ecosystem,accurately assess the value of ecosystem service,and help scientific understanding of reservoirs and humans.Direct or indirect contributions from well-being and benefits.This paper takes the Danjiangkou Reservoir and its subsidence area as the research object,based on remote sensing,hydrology,meteorology,land use,soil,digital elevation model and other data,combined with geographic information systems and remote sensing technology,comprehensive application of three-dimensional space surface analysis,geostatistics and other methods.A reservoir water quantity estimation method was proposed to analyze the dynamic changes of the water volume of the Danjiangkou reservoir over the past 17 years,and the dynamic process of the Danjiangkou reservoir water-level-fluctuating area was studied;the system of the Danjiangkou reservoir and its subsidence area was based on market theory,using the indirect material conversion method,estimates the value of ecosystem services in terms of climate regulation,oxygen release and carbon fixation,organic production,and water conservation..The main results achieved in this paper are:(1)From 2000 to 2016,the average annual water volume of Danjiangkou Reservoir was 10.548 billion cubic meters,the maximum water volume was 20.06 billion cubic meters,and the minimum water volume was 6.567 billion cubic meters.In the long run,the water volume of the Danjiangkou Reservoir shows an increasing trend.Compared with the water flow of the Middle Route Project of the South-to-North Water Transfer Project in 2014,the water volume gradually increases.The heightening of the dam and the enhancement of water storage are the direct causes of the increase in water volume.Judging from the average monthly water volume,June-October increased gradually,remained unchanged from October-December,gradually decreased from December-April April,and increased first and then decreased from April-June.Periodic artificial regulation and climate change are the driving forces for changes in the water volume of the Danjiangkou Reservoir.(2)Since the middle line of the South-to-North Water Diversion Project was flooded,the average water volume of the Danjiangkou Reservoir increased by 501 million cubic meters in the past two years compared with that before the water transfer,and the frequency of extreme water volume decreased by 16.83%,and the fluctuation of water volume increased significantly.From 2000 to 2016,the total water supply guarantee rate of the Danjiangkou reservoir was 54.4%based on the water demand of the water receiving area,and it was 100%in 2015 and 2016.However,during this period,there was also a period when water could not be transferred completely,usually In the first half of the year,especially in May,the contradiction between the supply and demand of water transport to the north is outstanding,and the reservoir operation and management should reasonably reduce the amount of water discharged before May,so as to meet the water demand in the water receiving area and leave sufficient storage capacity.(3)The total area of the fluctuating zone in 2000-2014 and 2014-2016 was 450km2 and 500km2,respectively.The average area of the inundation area was 192.16km2 and 258.58km2 respectively,and the average area of the dryout area was 257.84km2 and 241.42km2.The area of the inundation area With an increasing trend,the area of the dry-falling areas showed a decreasing trend;the subsidence areas had an anti-seasonal dry-wet alternating feature,and the area of the submerged area was small from March to August,and the submerged area was larger from September to February.(4)The ecosystem service value of Danjiangkou Reservoir is 10.474 billion yuan/month.The value of its sub-services is:water supply value of supply>climate adjustment value>hydropower generation value>carbon fixation and oxygen release value>(5)organic production value.The value of ecosystem services during the year was the largest in August and the smallest in January,which is closely related to the value of climate regulation.The change in water volume is a major factor in the fluctuation of ecosystem service value. |
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