AnnAGNPS(Annualized-AGNPS) model integrated with GIS was applied to small watershed that is rural area and examed its validation to non-point source management through calibration and verification using observed data. To look into applicability of AnnAGNPS, Unit-source method was used.
Through the CN value, simulated runoff was calibrated and was in a good agreement with the observed data. And using NY(nitrogen in yield), CYC(Crop Yield Unit Conversion)Factor, PY(phosphorus in yield), simulated nutrient source were calibrated and were presented accuracy over 80%.
To verification, the nutrient source data in 1998 was used. Simulated value with AnnAGNPS was fair as compared to the observed, but the value of unit source method was siginificantly different from the observed data.
To use unit source method, geographic characteristics of applied area and a lot of observed data were required. But the AnnAGNPS model was simulated to the real environment almost identically through GIS and is continuous distributed model So, it represent exact value.
Conclusively, AnnAGNPS model is fit to management non-point source of rural watershed. And Better prediction of nutrient source could be achieved by considering appropriate nutrient level at crop land.
And it suggested that through the experiment and investigation of land use characteristics, input parameter database must be structured to continuous non-point source management. Also the method of interface with GIS must be considered.
