南江의 BASINS/WinHSPF 모델適用에 關한 硏究

Abstract

Delivery ratio is a barometer to evaluate runoff characteristics of pollutants within basin areas. DR is critical to determine water quality target and allotment loads in the process of setting up basin management plans such as TMDL. unfortunately, however, calculation of DR under the condition of standard flow and that in unobserved basin is difficult in korea because of a lack of data. The target location of this research includes both point source and non-point source. Thereby, we selected BASINS/winHSPF for evaluation. Based on BASINS, the research established GIS data including basin map and riverine map. Together with that, it built a model by converting six weather factors to WDM files. The weather factors include precipitation from 2003 to 2006 of the target locations which had been divided into 40 sub-basin areas. The model boasts superior pre-analysis function with useful tools and utilities. Validation and verification of the model was conducted based on precipitation data collected at 7 locations and water quality data of another 8 locations. The fit efficiency of model and the regression coefficient which shows similarity between simulation values and observed values and observed values, were ranged from 68.4 to 77.4 and from 0.78 to 0.83 respectively, according to the locations. In addition, the percent difference of BOD, T-N, and T-P was from 1.2 to 32.9%, from 8.3 to 31.1%, and from 1.2 to 26.0% respectively, thereby BASINS/winHSPF which is selected in this study, is found to be appropriate for simulation of daily flow and water quality in target basins. DR was calculated utilizing discharge loads of unobserved sub-basin and delivery load of unobserved locations obtained not by actual evaluation but by simulation through validation & verification. annual average DR of BOD, T-N and T-P were 0.97~1.50, 2.23~3.21, and 0.81~1.09 respectively. Thereby, the level of T-N was highest. Net DR of dependent basin excluding influence of upstream basin was 1.50~1.70, 0.55~0.69, and 0.24~0.31, all of which are lower than those of independent basin area. As for DR of independent basin about which validation data was obtained, utilization of basin model such as BASINS/winHSPF is reasonable to reflect daily flow. And as for others with few data, regression obtained according to land use type is available. DR of dependent basin should exclude influence of upstrem basin. Thereby, it is required to select model which is able to calculate delivery by tributary as well as net delivery load via sheet flow. Utilizing the model suggested by this research, DR of unobserved basin will be calculated, which will help determine priorities in management of basin areas.