Establish Distributed Hydrological Model In Nalenggele Drainage Area

Water resource becomes the prime problem during the rapid development of Caidam basin. As the largest river in the basin, Nalenggele river plays an important role in solving the water resource among this area. So it is important to study the hydrological situation of the river. Unfortunately, there is little understanding to this river till far, so it is urgent to seek a new method to study the hydrological situation of the river.In the study of hydrology, computers and remote sensing software are introduced to simulate hydrological model of the distributed basin area. This model develops rapidly in recent times especially as the quick development of computers and further researches conducted on the physical process of the hydrological system and the broad application of remote sensing technology and geology information system as well. By analyzing the general situation of Nalenggele river and the merits and demerits of each model, the most opportune hydrological model that suits the river, namely TOPKAPT Model is adopted to conduct the simulation of the hydrological situation of the drainage area.Firstly, the meteorology and hydrology data such as the DEM data of the basin, the soil utility grid data, soil type data and vegetation data are collected as completely as possible. After treatment of the remotesensing data, the sub modules are built by the treatment of module in the ArcView software when the meteorology data and formulas in the TOPKAPI models are input, then the model is established by integration of the sub modules. Parameters contained in the model are regulated in order to get the most satisfactory effect in the simulation.In the process of model establishment, the drainage area is divided into several sub basins. The flow in each sub basin is calculated and then added together to get the runoff concentration of the main river. Parameters needed to be calculated in each sub basin are precipitation, evaporation, surface runoff, flow in the ground and soil mosture. The data of the precipitation and meteorology of the sub basins is interpolated into each basin. The flow in the cross-section of the mountain is calculated by the runoff flow of the sub basins.The drainage basin of Nalenggele river is special, in that in the middle and upper area of the river it is quite the same as other rivers in which runoff from slope into the sub-river and then to the main river, the difference is in the lower area. In the mouth of the lower river flows out of the mountain, Nalenggele river becomes to ground water completely as the thickness of the flushing and piling fan is great and comes out of the earth in the form of springs at the edge of the fan area. As the present hydrological model is not so advanced to simulate it, in this study hydrological simulation only to the middle and upper area of the river is conducted.The model is established finally after the analyzing and treatment of the remote sensing data, imputing and parsing of data, building of modules and rating of parameters. By analyzing the chart get from the model, the result shows: the flow of the river changes annually, the flow during summer and autumn occupies more than 87% of annual flow,especially the flow during July to September which occupies more than 60% of annual flow. With the shortage of the hydrological data of the river, it is impossible to compare in detail except the comparison and annual flow and simulated flow.