## 2 Materials and Methods
### Overall Methodology
#### 2.5.2 Watershed Model Development  
The SWAT Calibration and Uncertainty Procedures (SWAT-CUP) ([PERSON] and [PERSON], 2012) was initially used to conduct a sensitivity analysis of the model's parameters in the study area, followed by manual calibration and validation of the model for runoff. The SWAT 2012 version was used in the present study to simulate streamflow of the HBS watershed. The HBS was delineated into seven sub-watersheds and a total of 797 Hydrologic Response Units (HRUs) were created. The first three years (2004-2007) of the simulation period were \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Types** & **Product** & \begin{tabular}{c} **Temporal** \\ **Coverage** \\ \end{tabular} & \begin{tabular}{c} **Finet Temporal** \\ **Frequency** \\ \end{tabular} & \
\begin{tabular}{c} **Spatial Coverage** \\ **Resolution** \\ \end{tabular} &
\begin{tabular}{c} **Spatial** \\ **References** \\ \end{tabular} \\ \hline SbPPs & PERSIANN & 03/2000 to date & 1 h & 60\({}^{\circ}\) N-60\({}^{\circ}\) S & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & [PERSON] et al. (2013) \\  & PERSIANN-CSS & 2003 to date & 1 h & 60\({}^{\circ}\) N-60\({}^{\circ}\) S & 0.04\({}^{\circ}\)\(\times\) 0.04\({}^{\circ}\) & [PERSON] et al. (2013) \\  & PERSIANN-CDR & 1983 to date & 1 day & 60\({}^{\circ}\) N-60\({}^{\circ}\) S & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & [PERSON] et al. (2013) \\  & IMPA-3B42 & 1998 to 12/2019 & 3 h & 50\({}^{\circ}\) N-50\({}^{\circ}\) S & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & [PERSON] et al. (2016) \\  & IMPA-3B42R7 & 03/2000 to 122/2019 & 3 h & 60\({}^{\circ}\) N-60\({}^{\circ}\) S & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & [PERSON] \& [PERSON] (2015) \\  & IMERG & 03/2000 to present & 30 min & 90\({}^{\circ}\) N-90\({}^{\circ}\) S & 0.10\({}^{\circ}\)\(\times\) 0.10\({}^{\circ}\) & [PERSON] et al. (2016) \\  & MSWEP & 1979 to present & 3 h & Global & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & [PERSON] et al. (2019) \\  & CMORPH & 2002 to present & 30 min & 60\({}^{\circ}\) N-60\({}^{\circ}\) S & 0.027\({}^{\circ}\)\(\times\) 0.027\({}^{\circ}\) & [PERSON] et al. (2014) \\  & CHHRPS & 1981 to date & Daily & 50\({}^{\circ}\) N-50\({}^{\circ}\) S & 0.05\({}^{\circ}\)\(\times\) 0.05\({}^{\circ}\) & [PERSON] et al. (2010) \\ \hline GbGPPs & GPCC & 1988 to present & 1 day & Global & 1.0\({}^{\circ}\)\(\times\) 1.0\({}^{\circ}\) & [PERSON] et al. (2014) \\  & APHRODITE-V & 1988 to 2015 & 1 day & Monsoon Asia & 0.25\({}^{\circ}\)\(\times\) 0.25\({}^{\circ}\) & [PERSON]_ et al. (2015) \\  & \(\mathrm{V}\_{1901}\) & 1988 to 2015 & 1 day & Monsoon Asia & 0.05\({}^{\circ}\)\(\times\) 0.05\({}^{\circ}\) & [PERSON]_ et al. (2015) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Description of the precipitation products. treated as a warmup period in order to equilibrate between various water storages in the hydrological cycle. The streamflow gauging station kh.92 was used for calibration and validation of streamflow. The calibration period was 2007-2010 (4 years), while the validation period was 2011-2014 (4 years). In the SWAT model developed in this study, surface runoff was predicted by the Soil Conservation Service Curve Number (SCS-CN) method and potential evapotranspiration by the Hargreaves method. Detailed information on SWAT model development is explained in detail through [PERSON] et al. [58]. The SOL_AWC factor that controls the available soil water capacity. The ESCO factor, a parameter which controls depth distribution to meet the soil evaporative demand to account for the effects of capillary action. Groundwater flow-related sensitive parameters were GW_REVAP, ALPHA_BF, GW_DELAY, and GWQMN. GW_REVAP allows water to move to the overlying saturated/vadose zone from the underlying aquifer. Similarly, model parameter GW_DELAY controls the delay between water entering the soil profile and entering the underlying aquifer. GWQMN is the threshold depth of water in a shallow aquifer required for return flow to occur.