## 4 Results
### Sediment Export Estimation Using SDR Model
#### 4.7.2 Sediment Export Estimation of Predicted LULC under Scenario I  
Estimates of total and average sediment export under the predicted LULC between 2020 and 2029 under Scenario I (Trend of LULC evolution) and mean rainfall erosivity are presented in Table 21. As a result, the highest total and average sediment exports were about 58,798 tons and 65.97 tons/km\({}^{2}\), respectively, in 2026. The lowest total and average sediment exports were about 32,373 tons and 36.32 tons/km\({}^{2}\), respectively, in 2022.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline  & & \multicolumn{3}{c}{**Sediment Export**} \\ \cline{3-5}
**LULC Types** & **Area (km\({}^{2}\))** & \multicolumn{1}{c}{**Total (tons)**} &
\begin{tabular}{c} **Average** \\ **(tons/km\({}^{2}\))** \\ \end{tabular} & \% \\ \hline Urban and built-up area (UR) & **33.10** & - & - & - \\ Paddy field (PD) & **220.70** & \(2471.12\) & **11.19** & 0.80 \\ Field crop (FC) & **21.84** & \(7169.79\) & **328.26** & 23.57 \\ Para rubber (RB) & **19.78** & \(2555.61\) & **129.18** & 9.27 \\ Perennial trees and orchards (PO) & **79.22** & \(11\),578.36 & **146.15** & 10.49 \\ Forest land (FO) & **436.90** & \(246.47\) & **0.56** & 0.04 \\ Water body (WB) & **33.37** & - & - & - \\ Rangeland (RL) & **27.26** & \(323.29\) & **11.86** & 0.85 \\ Wetland (WL) & **16.41** & - & - & - \\ Miscellaneous land (ML) & **2.71** & \(2076.77\) & **765.57** & 54.97 \\ \hline
**Total** & **891.4** & **26,421.41** & & **100** \\ \hline \hline \end{tabular}
\end{table}
Table 20: Contribution of LULC type in 2019 to sediment exports.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \begin{tabular}{c} **Default** \\ **Value** \\ \end{tabular} & \begin{tabular}{c} **Minimum** \\ **Value** \\ \end{tabular} & \begin{tabular}{c} **Maximum** \\ **Value** \\ \end{tabular} & \
\begin{tabular}{c} **Adjusted** \\ **Value** \\ \end{tabular} &
\begin{tabular}{c} **Optimum** \\ **Value** \\ \end{tabular} \\ \hline \(K_{0}\) & 2 & 1 & 2 & 0.5 & 1 \\ \(IC_{0}\) & 0.5 & 0.1 & 1 & 0.1 & 1 \\ \(TEA\) & 1000 & 1000 & 1800 & 200 & 1800 \\ \hline \hline \end{tabular}
\end{table}
Table 19: Systematic model parameters and optimum value under calibration period.  
These results indicate that the primary influence of rainfall erosivity and LULC types in the RUSLE model affect sediment export, as has been suggested by many researchers [56; 57; 58; 59; 60]. The influence of rainfall erosivity on sediment export in this study was confirmed by simple linear regression analysis, resulting in Figure 7, with an R\({}^{2}\) value of 0.6424. This finding indicates that rainfall erosivity can explain the linear relationship with the sediment export by about 64%.  
Moreover, the contribution of the predicted LULC under Scenario I on sediment export between 2020 and 2029 indicated that miscellaneous land caused the highest average sediment export, with values between 819.56 tons/km\({}^{2}\) in 2022 and 1501.94 tons/km\({}^{2}\) in 2026. Meanwhile, forest land generated the lowest average sediment export, with values between 0.65 tons/km\({}^{2}\) in 2022 and 1.05 tons/km\({}^{2}\) in 2026.