Dynamic Research Of The Lijiang Heilongtan Spring System Based On The Time Series Analysis

The Old Town of Lijiang is located in the Northewest of Yunnan province.It is one of the Culture Heritage resort.It is well-rekownned both at home and abroad. Heilongtan spring system has three main sring groups.They are Heilon gtan spring groups, Qingxi spring groups and the Old town spring groups.Thes e three groups offer the domestic water,landscape water to the Old Town.But t he discharge of Heilongtan spring group is sharply reduced, and even cut off i n the dry season. The elevation of the Old town spring group is the lowest,its discharge also significantly reduced when the Heilongtan spring stop flow.Qing xi spring group which is one of the Lijiang drinking water sources locate in t he eastern margin of the Lijiang Basin.The time series method can extract the data structure and help us analyze the dynamic feature.The method is one of t he effective measures and significant ways to fugure out the hydrological proce ss.The paper analyses the hydrogeological condition of the Heilongtan spring system.The systemcan be divided into Heilongtan-Old town spring subsystem and the Qingxi spring subsystem according to the variations characteristic of t-he spring group discharge.On the basis of which,analyses the reason why Qing xi spring group is different from Heilongtan spring group. We set up an ARM A model to find out the difference of two spring groups according to the time series flow data of the spring system. Finally, combining with rainfall data, w e study the correlation of the rainfall and the spring flow and the respond mo de of the spring flow to the rainfall by establishing the VAR model.The main research achievements of this paper are as follows:(1)The spring system is mainly recharged by the rainfall from the Jiuziha i recharge area which is in the north of the spring system.The Heilongtan spri ng group and the old town spring group receive recharge through the runoff z ones from the Jiuzihai tothe Lijiang-Wenhua fault.The Qingxi spring groups rec eive recharge through the runoff zones from the Jiuzihai to Qingxi spring grou p.However,Qingxi spring group also accept the recharge from the snow mountain.(2)The Heilongtan spring group time series data is nonstationarity data whi ch can divided into the trend term and the random term.The data structure of Qingxi spring group time series is relativelysimple.The ARMA model results pr esent that the two spring groups all significantly related to the previous two da ta.(3)There are three obvious scale feature.Heilongtan spring group is 10~20,30~70 and150~256 month,and the 10~20 month scale is full spreading. Qingxi spring group is 15~20,30~60 and 90~128 month, and the 30~60 month scale is full spreading. Heilongtan spring group has four main cycle(188,121,153,18). And Qingxi spring group has three main cycle(115,47,18). The two spring grou p all act 12 months cycle characteristics in the time scale of 18.(4)In accessing the link between rainfall and spring flow, the connection is confirmed.(5)The VAR model of the spring flow and the rainfall show that the flow of Heilongtan spring group lag 3 months to the rainfall of Lijiang station,and the Qingxi spring group lag 1 month to the rainfall of Qingxi station.The reg ression equation also show the same characteristics.