The Impact Prediction Research Of The Dry-Hot River Valley Vegetation During The Operation Period Of Wudongde,Jinsha River Reservoir

Wudongde reservoir locates in the dry-hot valley of Jinsha river which is within the boundary of Yunnan and Sichuan provinces.The climate there is dry while rich in heat,and the local vegetation is secondary semi-savanna with a unique look and flora.The reservoir 's exploitation target mainly lays in generating electricity with flood-prevention and promoting local social economy in secondary.However,it's hard to avoid the damage in vegetation and ecosystem beyond those benefits.This study concentrated in assessing the level of destruction on Vegetation in Dry-Hot River Valley caused by this reservoir project and offering a reference to the vegetation restoration and the establishment of the policies.This approach studied the evaluation index system of the project's effects on vegetation based on theoretical analysis,then verified by field survey and emote-imaging in complement.The main conclusions are as following:(1)Based on Vegetation in Yunnan,the vegetation in the evaluate region can be divided into 5 vegetation type groups,7 vegetation type and 23 formations.The evaluate region mainly locates in the 900-1800m height belt.In the highland and plateau above 1600m the vegetation type is main highland aciculiailvae forest and hard-leaf evergreen broad-leaved forest while main Dry-hot River Valley thorn forest and scrub underneath 1600m because of the climate.For the diversity of region,landform and climate,the Jinsha River Valley ecosystem of the evaluate region varies a lot.(2)Combined quantification and qualification methods to forecast and evaluate the operation of the Jinsha river reservoir via setting up different gradations for the vegetation evaluation index system according to the characteristics of the regional vegetation which refered to Planning Environmental Assessment Biodiversity Impact Assessment Index System and Empirical.Besides,five system administrative levels,vegetation type's area and quantity,vegetation integrity,vegetation distribution range,vegetation character and vegetation dynamic behavior,were classified.The vegetation character is consisted of typicalness,original and fragility.These results indicated that this evaluate system was scientific and rigorous as well as simple and convenient which can manage the evaluation target.(3)The grading results gave a view that the reservoir slightly impacted on the vegetation type's area and quantity with a mark of 79.76;it slightly affected on vegetation integrity with a mark of 86.90;it had a small effect on the vegetation distribution range with a mark of 75.94;likewise,it had a small effect on vegetation character with a mark of 75.74;it impacted the vegetation dynamic behavior with a mark of 66.50.The synthetical impact was mild with a mark of 77.83.(4)The operation of the reservoir won't alter the vegetation system's structure and stability.The water surface of the valley will rise after the reservoir filling which can elevate the air humidity of the small environment along the bank.And these will be benefit to the restore by the valley vegetation itself.