| Year | Surface runoff | Change in surface runoff | |||||||
| 1987 | 2001 | 2015 | 2001-1987 | 2015-2001 | 2015-1987 | ||||
| Unit | mm | Mm | mm | mm | % | mm | % | mm | % |
| Surface runoff | 189.28 | 191.52 | 221.19 | 2.24 | 1.18 | 29.67 | 15.49 | 31.91 | 16.86 |