## 4 Results  
### Correlation between GPP and the Variables  
Generally, the productivity of groundwater is affected by various factors such as topography, hydrogeology, soil, forestation, and flow velocity [54]. To quantitatively analyze, we examined the relationship between the related factors using the FR and LR models. Table 3 shows the coefficients of the factors in each class range; they were calculated with respect to groundwater T and SPC values. In general, the relationship between slope gradient and groundwater is inversely proportional. Thus, when the slope gradient is high, it is difficult for groundwater to accumulate in the aquifer. For slopes between 0\({}^{\circ}\) to 5\({}^{\circ}\), the ratio was approximately 3.0, which indicated a high probability of GPP. The hydraulic slope gradient, relative slope position, valley depth, and slope-length (LS) were also found to be inversely proportional to GPP. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{3}{*}{**Factor**} & \multirow{3}{*}{**Class**} & \multicolumn{2}{c}{**No. of**} & \multirow{3}{*}{\% of**} & \multicolumn{3}{c}{T \(\geq\) 2.61 b  } & \multicolumn{3}{c}{**SPC \(\geq\) 4.88 **} & \multicolumn{3}{c}{**Regression**} \\  & & **Pixels in** & **Domain** & \multicolumn{3}{c}{**No. of**} & \multicolumn{3}{c}{**FR of**} & **No. of** & \multicolumn{3}{c}{**\"soft**} & **FR of** & **T.2** & **SPC** \\  & & & & **Data 1** & **Data 1** & **Data 1** & **Data 1** & **Data 1** & **Data 1** & **Data 1** & **Data 1** & **2.61** & \(\geq\) **4.88** \\ \hline  & \multicolumn{2}{c}{**0-5.11**} & **113,319** & **18.85** & **25** & **58.14** & **3.09** & **24** & **55.81** & **2.96** & & \\ Slope & 5.11-13.97 & 128,401 & 21.35 & 16 & 37.21 & 1.74 & 16 & 37.21 & 1.74 & & \\ gradient & 13.97-20.82 & 112,842 & 18.77 & 2 & 4.65 & 0.25 & 3 & 6.98 & 0.37 & \(-\)0.58 & \(-\)0.74 \\ (degree) & 20.82-28.18 & 118,770 & 19.75 & 0 & 0.00 & 0.00 & 0 & 0.00 & 0.00 & & \\  & 28.18-90 & 127,988 & 21.28 & 0 & 0.00 & 0.00 & 0 & 0.00 & 0.00 & & \\ \hline  & **0-5** & **154,281** & **25.66** & **33** & **36.74** & **2.99** & **35** & **51.40** & **3.17** & & \\ Hydraulic & 5-10 & 113,239 & 18.83 & 8 & 18.60 & 0.99 & 7 & 16.28 & 0.86 & & \\ slope (degree) & 10-20 & 178,203 & 29.65 & 2 & 4.65 & 0.16 & 1 & 2.33 & 0.08 & \(-\)0.40 & \(-\)0.84 \\  & 20-30 & 101,221 & 16.83 & 0 & 0.00 & 0.00 & 0 & 0.00 & 0.00 & & \\  & 30-90 & 54,276 & 9.03 & 0 & 0.00 & 0.00 & 0 & 0.00 & 0.00 & & \\ \hline  & **0-0.0275** & **118,886** & **19.64** & **17** & **39.53** & **201** & **22** & **51.16** & **2.61** & & \\ Relative & 0.0275-0.2235 & 122,639 & 20.40 & 19 & 44.19 & 2.17 & 14 & 32.56 & 1.60 & & \\ slope & 0.2235-0.7484 & 121,248 & 20.16 & 2 & 4.65 & 0.23 & 2 & 4.65 & 0.23 & 0.32 & \(-\)0.52 \\ position & 0.4784-0.7529 & 120,084 & 19.97 & 1 & 2.33 & 0.12 & 3 & 6.98 & 0.35 & & \\  & 0.7529-1 & 119,263 & 19.83 & 4 & 9.30 & 0.47 & 2 & 4.65 & 0.23 & & \\ \hline  & 0-19.1231 & 118,571 & 19.72 & 8 & 18.60 & 0.94 & 6 & 13.95 & 0.47 & & \\ Valley depth & 19.1231-3.0510 & 126,948 & 20.97 & 17 & 39.53 & 1.89 & 12 & 27.91 & 0.79 & & \\ (m) & 37.0510-58.5645 & 122,756 & 20.41 & 5 & 11.63 & 0.57 & 11 & 25.58 & 1.25 & \(-\)0.16 & \(-\)0.28 \\  & **85.645-88.443** & **119,847** & **19.95** & **10** & **23.26** & **1.17** & **8** & **18.60** & **1.42** & & \\  & 88.4443-304.7743 & 113,952 & 18.95 & 3 & 6.98 & 0.37 & 6 & 13.95 & 1.07 & & \\ \hline  & \multicolumn{2}{c}{\(-\)0.27-3.6} & 117,062 & 19.47 & 2 & 4.65 & 0.24 & 1 & 2.33 & 0.12 & & \\  & 36.4-3.15 & 129,046 & 21.46 & 2 & 4.65 & 0.22 & 3 & 6.98 & 0.33 & & \\ TWI & 4.35-54 & 118,685 & 19.74 & 3 & 6.98 & 0.35 & 2 & 4.65 & 0.24 & 0.02 & \(-\)0.11 \\  & **5.4-7.8** & **117,832** & **19.59** & **17** & **39.53** & **2.02** & 19 & **44.19** & **2.26** & & \\  & 7.8-25.37 & 118,695 & 19.74 & 19 & 44.19 & 2.24 & 18 & 41. In the case of hydrogeological factors, the frequency ratio was higher for unconsolidated clastic sediment areas (Table 3). It was 0 for carbonate rocks, dolomite rock, and non-porous volcanic rocks.