
Figure 1:
Study area map

Figure 2:
A flowchart of the study structure

Figure 3:
Sub-catchment delineation map for the MIKE NAM model

Figure 4:
Hydraulic network of the Red - Thai Binh River

Figure 5:
Results of model calibration in 2023: (a) Yen Bai station, (b) Ham Yen station, (c) Gia Bay station, (d) Thanh Son station, (e) Chu station
Table 1a:
Evaluation of errors in the MIKE NAM model
| Station | Nash | R2 | RMSE |
|---|---|---|---|
| 2023 | 2023 | 2023 | |
| Yen Bai | 0.91 | 0.93 | 255.68 |
| Ham Yen | 0.68 | 0.69 | 86.62 |
| Gia Bay | 0.88 | 0.89 | 7.72 |
| Thanh Son | 0.88 | 0.91 | 66.32 |
| Chu | 0.86 | 0.89 | 96.88 |

Figure 6:
Results of model validation in 2024: (a) Yen Bai station, (b) Ham Yen station, (c) Gia Bay station, (d) Thanh Son station, (e) Chu station
Table 1b:
Evaluation of errors in the MIKE NAM model
| Station | Nash | R2 | RMSE |
|---|---|---|---|
| 2024 | 2024 | 2024 | |
| Yen Bai | 0.92 | 0.94 | 793.34 |
| Ham Yen | 0.96 | 0.98 | 288.86 |
| Gia Bay | 0.98 | 0.99 | 93.72 |
| Thanh Son | 0.9 | 0.93 | 117.43 |
| Chu | 0.94 | 0.95 | 213.4 |

Figure 7:
Results of hydraulic model calibration in 2023: (a) Quang Cu station, (b) Son Tay station, (c) Ha Noi station, (d) Thuong Cat station, (e) Nam Dinh station, (f) Truc Phuong station, (g) Cat Khe station, (h) Quyet Chien station, (i) Trieu Duong station, (j) Cua Cam station
Table 2:
Evaluation of errors in the MIKE 11 hydraulic model
| No. | Station | Nash | R2 | ||
|---|---|---|---|---|---|
| 2023 | 2024 | 2023 | 2024 | ||
| 1 | Quang Cu | 0.76 | 0.80 | 0.77 | 0.85 |
| 2 | Son Tay | 0.84 | 0.86 | 0.87 | 0.88 |
| 3 | Ha Noi | 0.88 | 0.89 | 0.89 | 0.90 |
| 4 | Thuong Cat | 0.89 | 0.87 | 0.89 | 0.90 |
| 5 | Nam Dinh | 0.91 | 0.91 | 0.94 | 0.92 |
| 6 | Truc Phuong | 0.91 | 0.88 | 0.95 | 0.90 |
| 7 | Cat Khe | 0.90 | 0.84 | 0.94 | 0.86 |
| 8 | Quyet Chien | 0.94 | 0.92 | 0.95 | 0.92 |
| 9 | Trieu Duong | 0.83 | 0.86 | 0.87 | 0.89 |
| 10 | Cua Cam | 0.90 | 0.78 | 0.92 | 0.80 |

Figure 8:
Results of hydraulic model validation in 2024: (a) Quang Cu station, (b) Son Tay station, (c) Ha Noi station, (d) Thuong Cat station, (e) Nam Dinh station, (f) Truc Phuong station, (g) Cat Khe station, (h) Quyet Chien station, (i) Trieu Duong station, (j) Cua Cam station

Figure 9:
Training process of the LSTM artificial intelligence model

Figure 10:
Results of artificial intelligence model testing in 2024
Table 3:
Comparative evaluation of model errors
| No. | Station | Nash | R2 | RMSE |
|---|---|---|---|---|
| 1 | Quang Cu | 0.994 | 0.994 | 6.7 |
| 2 | Son Tay | 0.98 | 0.988 | 41.4 |
| 3 | Ha Noi | 0.995 | 0.997 | 18.1 |
| 4 | Thuong Cat | 0.914 | 0.984 | 74.2 |
| 5 | Nam Dinh | 0.991 | 0.992 | 11.3 |
| 6 | Truc Phuong | 0.987 | 0.989 | 8.8 |
| 7 | Cat Khe | 0.993 | 0.996 | 12.8 |
| 8 | Quyet Chien | 0.996 | 0.996 | 8.2 |
| 9 | Trieu Duong | 0.99 | 0.993 | 15.6 |
| 10 | Cua Cam | 0.874 | 0.876 | 23.4 |

Figure 11:
Water level forecasting toolkit interface

Figure 12:
Configuration interface of the toolkit

Figure 13:
Toolkit information
Table 4:
Evaluation of the forecasting results of the toolkit for Typhoon Wipha (07/2025)
| No. | Station | Observed (cm) | Forecasting (cm) | Error (%) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| t+6 | t+12 | t+18 | t+24 | t+6 | t+12 | t+18 | t+24 | t+6 | t+12 | t+18 | t+24 | ||
| 1 | Quang Cu | 2738 | 2742 | 2734 | 2735 | 2736 | 2737 | 2743 | 2738 | 0.1 | 0.2 | 0.3 | 0.1 |
| 2 | Hoa Binh | 1202 | 1205 | 1210 | 1212 | 1203 | 1204 | 1211 | 1215 | 0.1 | 0.1 | 0.1 | 0.2 |
| 3 | Lam Son | 2113 | 2097 | 2089 | 2077 | 2094 | 2087 | 2079 | 2067 | 0.9 | 0.5 | 0.5 | 0.5 |
| 4 | Son Tay | 560 | 588 | 610 | 615 | 546 | 581 | 609 | 611 | 2.4 | 1.1 | 0.2 | 0.7 |
| 5 | Ha Noi | 420 | 452 | 484 | 490 | 410 | 435 | 473 | 485 | 2.3 | 3.7 | 2.3 | 0.9 |
| 6 | Thuong Cat | 358 | 392 | 432 | 434 | 347 | 384 | 438 | 447 | 3.0 | 2.1 | 1.3 | 3.0 |
| 7 | Gia Bay | 2221 | 2215 | 2205 | 2203 | 2216 | 2215 | 2203 | 2203 | 0.2 | 0.0 | 0.1 | 0.0 |
| 8 | Chu | 394 | 371 | 370 | 344 | 383 | 369 | 353 | 345 | 2.8 | 0.5 | 4.5 | 0.2 |
| 9 | Binh Lieu | 7781 | 7766 | 7758 | 7751 | 7778 | 7761 | 7755 | 7746 | 0.0 | 0.1 | 0.0 | 0.1 |
| Hmax | Hmin | Hmax | Hmin | Hmax | Hmin | ||||||||
| 10 | Nam Dinh | 283 | 199 | 281 | 203 | 0.7 | 2.0 | ||||||
| 11 | Truc Phuong | 267 | 135 | 261 | 140 | 2.2 | 3.7 | ||||||
| 12 | Ben Binh | 240 | 129 | 237 | 132 | 1.3 | 2.3 | ||||||
| 13 | Cat Khe | 243 | 155 | 235 | 157 | 3.3 | 1.3 | ||||||
| 14 | Ba Nha | 228 | 42 | 223 | 41 | 2.2 | 2.4 | ||||||
| 15 | Quyet Chien | 287 | 202 | 274 | 201 | 4.5 | 0.5 | ||||||
| 16 | Trieu Duong | 315 | 229 | 303 | 238 | 3.8 | 3.9 | ||||||
| 17 | Ba Lat | 230 | 10 | 234 | 11 | 1.7 | 10.0 | ||||||
| 18 | Cua Cam | 197 | −48 | 192 | −46 | 2.5 | −4.2 | ||||||
| 19 | Trung Trang | 229 | 22 | 225 | 21 | 1.7 | 4.5 | ||||||
Table 5:
Evaluation of the forecasting results of the toolkit for Typhoon Kajiki (08/2025)
| No. | Station | Observed (cm) | Forecasting (cm) | Error (%) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| t+6 | t+12 | t+18 | t+24 | t+6 | t+12 | t+18 | t+24 | t+6 | t+12 | t+18 | t+24 | ||
| 1 | Quang Cu | 2811 | 2849 | 2828 | 2798 | 2808 | 2810 | 2822 | 2827 | 0.1 | 1.4 | 0.2 | 1.0 |
| 2 | Hoa Binh | 964 | 1043 | 941 | 933 | 939 | 1005 | 962 | 923 | 2.6 | 3.7 | 2.3 | 1.0 |
| 3 | Lam Son | 2123 | 2106 | 2097 | 2091 | 2098 | 2097 | 2093 | 2089 | 1.2 | 0.4 | 0.2 | 0.1 |
| 4 | Son Tay | 673 | 701 | 710 | 698 | 651 | 698 | 692 | 691 | 3.2 | 0.4 | 2.5 | 1.0 |
| 5 | Ha Noi | 521 | 555 | 574 | 580 | 507 | 533 | 563 | 578 | 2.6 | 4.0 | 1.9 | 0.3 |
| 6 | Thuong Cat | 468 | 498 | 518 | 526 | 446 | 481 | 507 | 516 | 4.7 | 3.3 | 2.1 | 1.8 |
| 7 | Gia Bay | 2313 | 2332 | 2332 | 2301 | 2325 | 2327 | 2329 | 2305 | 0.5 | 0.2 | 0.1 | 0.2 |
| 8 | Chu | 820 | 938 | 830 | 699 | 824 | 949 | 822 | 674 | 0.5 | 1.1 | 1.0 | 3.6 |
| 9 | Binh Lieu | 7756 | 7749 | 7743 | 7738 | 7751 | 7744 | 7740 | 7734 | 0.1 | 0.1 | 0.0 | 0.1 |
| Hmax | Hmin | Hmax | Hmin | Hmax | Hmin | ||||||||
| 10 | Nam Dinh | 294 | 234 | 290 | 235 | 1.4 | 0.4 | ||||||
| 11 | Truc Phuong | 211 | 153 | 215 | 157 | 1.9 | 2.6 | ||||||
| 12 | Ben Binh | 269 | 225 | 269 | 224 | 0.1 | 0.4 | ||||||
| 13 | Cat Khe | 319 | 270 | 313 | 278 | 1.9 | 3.0 | ||||||
| 14 | Ba Nha | 157 | 129 | 156 | 126 | 0.6 | 2.3 | ||||||
| 15 | Quyet Chien | 300 | 240 | 293 | 240 | 2.3 | 0.1 | ||||||
| 16 | Trieu Duong | 344 | 284 | 348 | 278 | 1.2 | 2.1 | ||||||
| 17 | Ba Lat | 145 | 83 | 141 | 79 | 2.8 | 4.8 | ||||||
| 18 | Cua Cam | 79 | 26 | 74 | 28 | 6.3 | 7.7 | ||||||
| 19 | Trung Trang | 137 | 89 | 139 | 89 | 1.5 | 0.1 | ||||||

