Basic Theory of AGNPS
AGNPS developed based on Stanford Watershed Model
The basic theories of AGNPS are:
1. Curve Number Method developed by Soil Conservation Service ( USDA SCS, 1972 and 1986) is a well-known hydrological method in the world. There are many hydrological models were developed based on the method (such as SWACROP, SWATRE, SALTBAL) and
2. Universal Soil Loss Equation (USLE): developed by Wischneier and Smith, 1978, is another well-known model for predicting soil erosion from agricultural fields. However, recently we found it was not suitable to the conditions of our country especially in our province and the formula is too general, it is influenced by many factors. So, we are looking for another good method to calculate soil erosion.
Both Models are empirical approach with a focus on past
experiences and large scale field tests are needed for parameters.