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From the work of McMahon et al. (2013), it has been observed that it is quite difficult to estimate the values of KC for forest exactly, due to variation of KC depending upon different characteristics of trees in a forest. We have chosen the baseline value of KC of forest as 1 from the FAO 56 guidelines (Allen et al. 1998) and varied the value between 0.7 and 1.1 as it is expected to remain to be so for both the catchments. But the Tungabhadra River Basin (up to Haralahalli gauge station) is mainly crop dominated. Thus we have taken the baseline value of KC as 0.75 for crop and then varied the value between 0.7 and 0.9 as it is expected to be so in that watershed and determined the changes in water yield with respect to baseline run, which is shown in Table 4. We have also varied the values of precipitation and ET0 and compared the results with the baseline run for each of the basins. The ranges of sensitivity analysis of different parameters are given in Table 5.

Table 4

Variation of water yield at baseline (KC Forest = 1 and KCCrop = 0.75) with changes in KC values of both forest and crop in Tungabhadra River Basin (up to Haralahalli gauge station)

Study areaForest KCCrop KC% Change in crop KC % Change of water yield w.r.t baseline
Tungabhadra River Basin (up to Haralahalli gauge station) 0.7 −10 2.71 
0.75 
0.825 10 −3.69 
0.9 20 −6.98 
1.1 0.7 −10 1.53 
0.75 −1.18 
0.825 10 −4.87 
0.9 20 −8.15 
0.9 0.7 −10 3.57 
0.75 1.33 
0.825 10 −2.83 
0.9 20 −6.12 
0.8 0.7 −10 4.79 
0.75 2.77 
0.825 10 −1.6 
0.9 20 −4.89 
0.7 0.7 −10 6.2 
0.75 4.17 
0.825 10 −0.2 
0.9 20 −3.49 
Study areaForest KCCrop KC% Change in crop KC % Change of water yield w.r.t baseline
Tungabhadra River Basin (up to Haralahalli gauge station) 0.7 −10 2.71 
0.75 
0.825 10 −3.69 
0.9 20 −6.98 
1.1 0.7 −10 1.53 
0.75 −1.18 
0.825 10 −4.87 
0.9 20 −8.15 
0.9 0.7 −10 3.57 
0.75 1.33 
0.825 10 −2.83 
0.9 20 −6.12 
0.8 0.7 −10 4.79 
0.75 2.77 
0.825 10 −1.6 
0.9 20 −4.89 
0.7 0.7 −10 6.2 
0.75 4.17 
0.825 10 −0.2 
0.9 20 −3.49 
Table 5

Range of sensitivity of parameters

Study areaDataTypeValue (range and mean)SourceRange of sensitivity analysis
Sutlej River Basin Precipitation Raster (298.5–272.94 mm); 548.4 mm IMD ±20% 
ET0 Raster (384–1,526 mm); 628 mm IMD ±10% 
DEM Raster 30 m (526–7,429 m; 4,653.2 m) ASTER DEM  N.A. 
LULC  Raster See Table 3  Landsat imagery N.A. 
Root restricting layer depth Raster (0–1,524 mm); 1,040 mm FAO soil maps  N.A. 
PAWC Raster (001–0.272); 0.12144 SPAW N.A. 
KC Per LULC class See Table 3  Allen et al. (1998) (−30%; +10%) 
Z Constant 13 Xu et al. (2013)  (1–30) 
Tungabhadra River Basin Precipitation Raster (826.298–2,220.22 mm); 1,424.57 mm IMD ±20% 
ET0 Raster (1,549.78–1,707.53 mm); 1,635.84 mm IMD ±10% 
DEM Raster 30 m Cartosat-1, Bhuvan, ISRO  N.A. 
LULC  Raster See Table 3  LISS-III Imagery N.A. 
Root restricting layer depth Raster (0–1,000 mm); 1,000 mm FAO soil maps  N.A. 
PAWC Raster (0.1107–0.1285); 119 Using SPAW N.A. 
KC Per LULC Class See Table 3  Allen et al. (1998)  (−30%; +10%) 
Z Constant 10 Xu et al. (2013) (1–30) 
Study areaDataTypeValue (range and mean)SourceRange of sensitivity analysis
Sutlej River Basin Precipitation Raster (298.5–272.94 mm); 548.4 mm IMD ±20% 
ET0 Raster (384–1,526 mm); 628 mm IMD ±10% 
DEM Raster 30 m (526–7,429 m; 4,653.2 m) ASTER DEM  N.A. 
LULC  Raster See Table 3  Landsat imagery N.A. 
Root restricting layer depth Raster (0–1,524 mm); 1,040 mm FAO soil maps  N.A. 
PAWC Raster (001–0.272); 0.12144 SPAW N.A. 
KC Per LULC class See Table 3  Allen et al. (1998) (−30%; +10%) 
Z Constant 13 Xu et al. (2013)  (1–30) 
Tungabhadra River Basin Precipitation Raster (826.298–2,220.22 mm); 1,424.57 mm IMD ±20% 
ET0 Raster (1,549.78–1,707.53 mm); 1,635.84 mm IMD ±10% 
DEM Raster 30 m Cartosat-1, Bhuvan, ISRO  N.A. 
LULC  Raster See Table 3  LISS-III Imagery N.A. 
Root restricting layer depth Raster (0–1,000 mm); 1,000 mm FAO soil maps  N.A. 
PAWC Raster (0.1107–0.1285); 119 Using SPAW N.A. 
KC Per LULC Class See Table 3  Allen et al. (1998)  (−30%; +10%) 
Z Constant 10 Xu et al. (2013) (1–30) 

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