Different hydrologic/water quality model such as Soil and Water
Assessment Tool (SWAT), Hydrological Simulation Program-Fortran
(HSPF), Long-Term Hydrologic and Nonpoint Source Pollution (TTHIA),
and Agricultural Nonpoint Source (AGNPS) model has been
used to assess the water quality on watershed scale. Out of all the
models, SWAT has been used extensively throughout the world to
evaluate water quality effect due to its better predicting capacity
compared to others. The required model inputs are elevation, land
use, soil, management practice, precipitation, temperature,
observed streamflow, and water quality data. The model is calibrated
and validated based on observed streamflow data and water