Since there may be mutation points with low mutation reliability in the testing process of this method, considering that there are multiple mutation years that pass the 90% significance test, the mean difference T-test (Table 3) is used to verify the double mutation of the results. The study finally attributed the sudden change in the hydrological evolution of the Jialing River Basin to 1985.
Table 3
Results of Mann–Kendall analysis of the runoff discharge variation trend at the main hydrologic stations in the Jialing River
| Hydrometric station | Beibei | Xiaoheba | Wusheng | Luoduxi |
|---|---|---|---|---|
| ZC | −2.69 | −3.29 | −2.44 | −0.86 |
| Inspection criterion |  |  |  |  |
| Tendency | Significant reduction | Significant reduction | Significant reduction | Insignificant reduction |
| Hydrometric station | Beibei | Xiaoheba | Wusheng | Luoduxi |
|---|---|---|---|---|
| ZC | −2.69 | −3.29 | −2.44 | −0.86 |
| Inspection criterion | | | | |
| Tendency | Significant reduction | Significant reduction | Significant reduction | Insignificant reduction |