| One of the most urgent problems affecting arid and semi-arid region of China is water shortages.Utilization of flood water resources is an important way of relieving the tension.The river-lake connection project which succeeds in enhancing hydraulic relation of rivers,lakes,reservoirs and wetlands provides strong support for floodwater diversion and storage.The paper looked at the Interconnected River-Lake System of Baicheng,western Jilin province,studying the floodwater resources utilization of Taoerhe river.First,a model of one-dimensional floodwater diversion and storage was built by MIKE11.Next,using different calculation methods,the boundary thresholds were determined,at the same time,the author analyzed the impact of floodwater diversion.At last,the Analytic Hierarchy Process(AHP)was used to assess the priority of intake area,the schemes were presented according to specific principles,and the benefit assessment was given.This study is significant to the dispatching decision of Interconnected River-Lake System Network.This study yielded the follow conclusions:(1)The security of levee bank will be threatened when the return period of flood events are 20 years.The gate can open for diversion when the return period of flood events are 20years,the maximum safe flow of the river is 2140 m~3/s.The ecological base flow in different segments of the river is 2.79 m~3/s,2.50 m~3/s,1.29 m~3/s respectively.The upper limit value of all ponds water demand is 443 million m~3,and the lower limit is 84 million m~3;The upper limit value of wetland ecological water demand is 339 million m~3,and the lower limit is 275million m~3.The upper limit value of irrigated area water demand is 203 million m~3,and the lower limit is 199 million m~3.The limit value of all intake area outside the channel is 985million m~3,and the lower limit is 558 million m~3.(2)The water level of each typical section of the channel decreased after the floodwater diversion in different frequency flood conditions,and the change amount was between0.07~0.55 meters.The monthly average flow rate of each typical section decreased,and the change amount was between 24.85~184.41 m~3/s.After the floodwater diversion,the minimum flow rate of the flood discharge section of different frequency is greater than the ecological flow of the river,which has no great influence on the ecological environment of the river.The average water level of the moon-lake reservoir decreased by 0.09 meters and the water inflow volume was reduced to 1.587 billion m~3 for many years.In general,the water diversion for the intake area has little effect on the river channel and reservoir,and it is beneficial to flood contrl.(3)After the floodwater diversion,the total flood utilization volume is 504 million m~3 in dry years,it can conserve wetland about 538.67 km~2,provide water area of aquaculture and reed development about 177.05 km~2,irragate fields about 33.63 km~2.The total flood utilization volume is 842 million m~3 in normal years,it can conserve wetland about 602.67km~2,provide water area of aquaculture and reed development about 433.47 km~2,irragate fields about 97.73 km~2.The total flood utilization volume is 854 million m~3 in normal years,it can conserve wetland about 602.67 km~2,provide water area of aquaculture and reed development about 433.47 km~2,irragate fields about 108.67 km~2.Utilization of floodwater resources is profitable,and it can effectively contribute to ecologicalrestoration and agricultural development at regional scale. |
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