## 4 Results
### Sediment Export Estimation Using SDR Model
#### 4.7.4 Sediment Export Estimation of Predicted LULC under Scenario III  
The estimated total and average sediment export under the predicted LULC between 2020 and 2029 and mean rainfall erosivity according to Scenario III (Economic crop zonation) are presented in Table 23. As a result, the highest total and average sediment exports were about 76,068 tons and 85.34 tons/km\({}^{2}\), respectively, in 2026. The lowest total and average sediment exports are about 34,520 tons and 38.73 tons/km\({}^{2}\), respectively, in 2022. As with Scenario I, these results indicate that the primary influence of rainfall erosivity factor and LULC types in the RUSLE model affected sediment export; however, the influence of rainfall erosivity on sediment export under Scenario III was lower than that under Scenario I, as shown in Figure 9. The simple linear equation indicates a moderately positive correlation between the mean rainfall erosivity factor and average sediment export under Scenario III, with an R value of 0.5235 and R\({}^{2}\) value of 0.274. According to the R\({}^{2}\) value, the rainfall erosivity can explain the linear relationship with sediment export by only 27%. Figure 8: Relationship between mean rainfall erosivity and average sediment export under Scenario II. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Year**} & \multicolumn{2}{c}{**Sediment Export**} & \multicolumn{2}{c}{**Mean Rainfall Erosivity**} \\ \cline{2-4}  & **Total (tons)** & **Average (tons/km\({}^{2}\))** & **(MJ mm ha\({}^{-1}\) h\({}^{-1}\) y\({}^{-1}\))** \\ \hline
2020 & 40,979.13 & 45.97 & 2854.33 \\
2021 & 34,149.06 & 38.31 & 2490.34 \\
2022 & 30,190.61 & 33.87 & 2239.93 \\
2023 & 38,483.96 & 43.17 & 2711.93 \\
2024 & 35,659.13 & 40.01 & 2601.06 \\
2025 & 41,526.64 & 46.59 & 2992.66 \\
2026 & 48,115.01 & 53.98 & 3130.43 \\
2027 & 33,851.75 & 37.98 & 2456.18 \\
2028 & 36,216.79 & 40.63 & 2588.82 \\
2029 & 37,599.82 & 42.18 & 2640.18 \\ \hline
**Average** & **37,677.19** & **42.27** & **2670.59** \\ \hline \hline \end{tabular}
\end{table} 
Table 22: Estimation of sediment export between 2020 and 2029 under Scenario II. The contribution of the predicted LULC under Scenario III to sediment export between 2020 and 2029 reveals that miscellaneous land caused the highest average sediment export, with values between 1658.33 tons/km\({}^{2}\) in 2022 and 7372.09 tons/km\({}^{2}\) in 2029, while forest land generated the lowest average sediment export, with values between 0.65 tons/km\({}^{2}\) in 2022 and 1.08 tons/km\({}^{2}\) in 2026. The average sediment export between 2020 and 2029 under the three scenarios was then compared, as shown in Figure 10, which shows that the predicted LULC under Scenario II (Maximization of ecosystem service values) delivered the lowest annual sediment export, compared to Scenarios I and III, with an average value of 42.27 tons/km\({}^{2}\) due to the increasing areas of wetland and decreasing areas of rangeland and miscellaneous land. In contrast, the areas of miscellaneous land in scenarios I and III were increased, based on the annual change rate of the Markov chain model. Though miscellaneous land showed only a minor increase, it caused high soil loss and sediment export. Moreover, Scenario III delivered the highest annual sediment export when compared to the other scenarios, as the paddy field and field crop areas increased, according to economic crop zonation by the LDD in 2018.