| Wetland is the unique ecosystem on earth and it is one of the richest biodiversity and the highest ecological function in nature and one of the most important environmental resources for human. It is known as the "kidney of the earth", called the three ecosystems in the world with forest and ocean. Water is the most important transport intermediary in wetland ecosystem and is the decisive factor in wetland. The wetland exchange energy through the hydrological process, which controls the formation and evolution of the wetland and it also restricts the biological, physical and chemical characteristics of the wetland environment. Since the early twentieth century, the continuous of wetland hydrology process has been interfered seriously by the increasing human activities. To research on wetland hydrology process by method of hydrological model to simulate and predict wetland hydrology will provide a scientific basis and technical support for the restoration and protection of wetland.Hydrological model is always one of the important means and method of hydrological science research. Due to the complexity of the unique wetland ecosystem and wetland eco hydrological process, the traditional method of wetland hydrology study is to obtain information through field investigation and observation, Including rainfall, water level, flow, flood process est. But the poor working conditions, hydrological and meteorological observation data of wetland is low; at the same time, the traditional watershed hydrological model which is applied to the wetland will also appear on the applicability problem. With the development of hydrological science, detection technology and computer and the progress of geographic information system (GIS) and remote sensing (RS), in order to adapt to the need of hydrology and water resources study under the impact of climate change and human activities, hydrological model obtained great development, it has been extended from the lumped model to distributed or semi distributed model.According to the basic process of rainfall-runoff, this study has established a grid type distributed hydrological model for a single rainfall-runoff event in full consideration of the spatial heterogeneity of watershed underlying surface hydrological factors and various parameters and combination with the characteristics of the study area. The calibration of the model was conducted using the data collected from the gauge stations.Conclusions were as follows:(1) The study of the distributed model. This model discretizes watershed into grid unit based on the DEM and divides the rainfall-runoff process into two parts, runoff generation and confluence. The runoff generation is calculated by SCS Model which takes the vegetation types and soil types into consideration. According to the the characteristic of flow, the confluence is calculated respectively by the kinematic wave equation and the Muskingum-Cunge method based on the idea of hierarchical routing convergence. The runoff was routed from the watershed to the outlet using the ranked-grid based routing method.(2) Model parameter. The model parameters are less, the physical meanings of parameters are clear, most of the parameters can be obtained by DEM, land use map and soil type determination; it need less parameters, easy to use.(3) The validation and application of the model. Wolvlanhe watershed, located in Honghe National Wetland Nature Reserve in Heilongjiang province was chosen as the study area. The simulation effect of the model is evaluated by deterministic coefficient, relative error of flood discharge and flood peak, absolute error of flood time. This model is inspected by the observed data in the study area, the result shows that the deterministic coefficient is above0.8, the relative error of flood discharge and flood peak basic within10%and the absolute error of flood time is less than2hours. |
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