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In the sensitivity analysis of SWAT model using the SUFI-2 algorithm of SWAT-CUP software, the minimum and maximum values of different parameters were obtained from the literature and then the fitted (optimum) values of the parameters were obtained through iteration until the best agreement between observed and simulated runoff was achieved, using R² as an objective function (Bizuneh et al. 2021). These parameters were ranked based on their t-stat value during global sensitivity analysis. The list of selected parameters used for the SWAT model calibration and their optimal values are presented in Table 3.

Table 3

Most sensitive parameters optimized value and rank for the SWAT model

Parameter	Description	Min value	Max value	Fitted value	Rank
CN2.mgt	SCS runoff CN	35	98	61.14	1
ALPHA_BF.gw	Base flow alpha factor	0	1	0.875	2
GW_DELY.gw	Groundwater delay	0	500	262	3
SOL_K.sol	Saturated hydraulic conductivity	0	2,000	41	4
GW_REVAP.gw	Groundwater ‘revap’ coefficient	0.02	0.2	0.18	5
GWQMN.gw	A threshold minimum depth of water in the shallow aquifer for base flow to occur	0	5,000	267.5	6
SOL_AWC.sol	Available water capacity of the soil layer	0	1	0.55	7
HRU_SLP.hru	Average slope steepness	0	1	0.59	8
SURLAG.bsn	Surface runoff lag time	0.05	24	0.845	9

Parameter	Description	Min value	Max value	Fitted value	Rank
CN2.mgt	SCS runoff CN	35	98	61.14	1
ALPHA_BF.gw	Base flow alpha factor	0	1	0.875	2
GW_DELY.gw	Groundwater delay	0	500	262	3
SOL_K.sol	Saturated hydraulic conductivity	0	2,000	41	4
GW_REVAP.gw	Groundwater ‘revap’ coefficient	0.02	0.2	0.18	5
GWQMN.gw	A threshold minimum depth of water in the shallow aquifer for base flow to occur	0	5,000	267.5	6
SOL_AWC.sol	Available water capacity of the soil layer	0	1	0.55	7
HRU_SLP.hru	Average slope steepness	0	1	0.59	8
SURLAG.bsn	Surface runoff lag time	0.05	24	0.845	9

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