The model was calibrated over the five years from 2001 to 2005 for Nam Kim and Ngoi Hut. Some sensitive parameters were adjusted, as summarized in Table 1. Note that some final values were averaged from the values of hydrologic response units (HRUs). Model validation was applied after every calibration from 2006 to 2012. The goodness of agreement between the simulated data and the observed data were evaluated using the coefficient of determination (R2), the Nash–Sutcliffe simulation efficiency coefficient (NSE) and graphical methods. These methods were also applied for BEACH and KINEROS2.
Top ten SWAT sensitive parameter and final values
| Sensitivity order . | Parameter . | Description . | Unit . | Range . | Initial value . | Final value . |
|---|---|---|---|---|---|---|
| 1 | CN2 | Curve number condition 2 | – | 35–98 | 35 | 54.1 |
| 2 | Alpha_Bf | Baseflow recession constant | days | 0–1 | 0.04 | 0.4 |
| 3 | Ch_K2 | Effective hydraulic conductivity in channel | mm hr−1 | −0.01–500 | 50 | 75 |
| 4 | Sol_K | Saturated hydraulic conductivity | mm hr−1 | 0–2,000 | 2 | 4.30 |
| 5 | Ch_N2 | Manning n value for the main channel | – | −0.01–0.3 | 0.015 | 0.05 |
| 6 | Surlag | Surface runoff lag coefficient | – | 1–24 | 4 | 2.5 |
| 7 | Sol_Awc | Available water capacity | mm mm−1 | 0–1 | 0.22 | 0.31 |
| 8 | Gw_Revap | Revap coefficient | – | 0.02–0.2 | 0.02 | 0.2 |
| 9 | Esco | Soil evaporation compensation factor | – | 0-1 | 0 | 0.95 |
| 10 | Gwqmin | Threshold water level in shallow aquifer for base flow | mm | 0–5,000 | 0 | 0.50 |
| Sensitivity order . | Parameter . | Description . | Unit . | Range . | Initial value . | Final value . |
|---|---|---|---|---|---|---|
| 1 | CN2 | Curve number condition 2 | – | 35–98 | 35 | 54.1 |
| 2 | Alpha_Bf | Baseflow recession constant | days | 0–1 | 0.04 | 0.4 |
| 3 | Ch_K2 | Effective hydraulic conductivity in channel | mm hr−1 | −0.01–500 | 50 | 75 |
| 4 | Sol_K | Saturated hydraulic conductivity | mm hr−1 | 0–2,000 | 2 | 4.30 |
| 5 | Ch_N2 | Manning n value for the main channel | – | −0.01–0.3 | 0.015 | 0.05 |
| 6 | Surlag | Surface runoff lag coefficient | – | 1–24 | 4 | 2.5 |
| 7 | Sol_Awc | Available water capacity | mm mm−1 | 0–1 | 0.22 | 0.31 |
| 8 | Gw_Revap | Revap coefficient | – | 0.02–0.2 | 0.02 | 0.2 |
| 9 | Esco | Soil evaporation compensation factor | – | 0-1 | 0 | 0.95 |
| 10 | Gwqmin | Threshold water level in shallow aquifer for base flow | mm | 0–5,000 | 0 | 0.50 |