## 3 Case Study
### Results and Discussion  
The discharges and water levels of the four verification samples were obtained according to the real-time operation procedure depicted in Figure 1 and are plotted together with the measured inflows, discharges, and water levels in Figures 3-6. The maximum discharge and water level are listed in Table 4, in which 1 represents flood regulation results obtained using the DT-based rules, 2 represents the measured values, and 3 represents the flood regulation results based on the conventional operation rules. The relative errors of the maximum discharge and maximum water level reported in Table 4 were determined, respectively, by the following:  
\[r_{q}=\frac{|q_{\max DT}-q_{\max}|}{q_{\max DT}}\times 100\% \tag{5}\]  
\[z_{q}=\frac{|z_{\max DT}-z_{\max}|}{z_{\max DT}}\times 100\% \tag{6}\]  
where \(q_{\max DT}\) is the maximum discharge according to DT-based rules; \(z_{\max DT}\) is the maximum water level according to DT-based rules; \(q_{\max}\) is the measured maximum discharge or the maximum discharge determined by the conventional operation rules; and \(z_{\max}\) is the measured maximum water level or the maximum water level determined by the conventional operation rules. Figure 4: Operation hydrographs for 22 July 2020. Figure 3: Operation hydrographs for 12 Aug 2019.  
the operating scheme formulated using the conventional operation rules was the smallest; the relative errors between 1 and 2 and between 1 and 3 were both small (0.3% and 0.48%, respectively). It can be observed that the operating scheme formulated using the conventional operation rules was the best in terms of reservoir safety because its maximum water level was the smallest. However, this condition was the most unsafe downstream because the corresponding maximum discharge was the largest. The measured operating scheme was the best in terms of downstream safety because its maximum discharge was the smallest. However, this condition exhibited the highest maximum water level, indicating that it was the worst operating scheme in terms of reservoir safety. The maximum discharge and maximum water level provided by the operating scheme formulated using the DT-based rules were between those of the measured values and the operating scheme formulated using the conventional operation rules. At the same time, the maximum discharge of 1200 m\({}^{3}\)/s provided by the operating scheme formulated using the DT-based rules remained below the controlled discharge of 1900 m\({}^{3}\)/s, indicating that it realized a suitable compromise and is therefore feasible. 2. For the 22 July 2020 flood, the maximum discharge of the operating scheme formulated using the conventional operation rules was the largest, followed by the measured maximum discharge, while the maximum discharge of the operating scheme formulated using the DT-based rules was the smallest; the relative error between 1 and 2 was small (24.23%) whereas the relative error between 1 and 3 was large, reaching 137.53%. The measured maximum water level was the largest, followed by the maximum water level of the operating scheme formulated using the conventional operation rules, while that of the operating scheme formulated using DT-based rules was the smallest; the relative errors between 1 and 2 and between 1 and 3 were both small (0.36% and 0.07%, respectively). It can be observed that the operating scheme formulated using the DT-based rules was the best in terms of both reservoir safety and downstream safety because its water level and discharge were simultaneously the smallest. At the same time, the discharge of 421 m\({}^{3}\)/s dictated by the operating scheme formulated using the DT-based rules was less than the control discharge of 1000 m\({}^{3}\)/s, confirming that this operating scheme was indeed the best among the three evaluated for this flood. 3.