| Title: | Understanding the main causes of runoff change by hydrological modeling: A case study in Luanhe River Basin, north China |
| Authors: | Zhang, T., Y. Wang, B. Wang and P. Feng |
| Year: | 2018 |
| Journal: | Water |
| Volume (Issue): | 10(8) |
| Pages: | |
| Article ID: | 1028 |
| DOI: | 10.3390/w10081028 |
| URL (non-DOI journals): | |
| Model: | SWAT |
| Broad Application Category: | hydrologic only |
| Primary Application Category: | climate change and land use change |
| Secondary Application Category: | calibration, sensitivity, and/or uncertainty analysis |
| Watershed Description: | 44,750 km^2 Luanhe river, located in northeast China. |
| Calibration Summary: | |
| Validation Summary: | |
| General Comments: | |
| Abstract: | In the traditional point of view, if there is a significant decreasing trend for a runoff time
series, while no significant trend for a precipitation series is present, then an unreliable conclusion
will be made that the land surface change is the main contributor to the runoff change. To test it,
we selected four sub-watersheds in the Luanhe river basin as the study areas where land use has
changed severely. We first detected the long-term rainfall and runoff trend by the Mann-Kendall test,
Sen's slope, and the moving average method, and found that the runoff had a decreasing trend at the
0.05 significance level, while the rainfall had no significant trend in all sub-watersheds. Then an orderly
cluster analysis and moving T test method were used to detect the change point of the runoff series.
We quantified the contributions of the land surface change and climate variability based on Soil and
Water Assessment Tool (SWAT), and the contribution of climate variability accounted for more than 50%,
which implies that climate change is the main factor of runoff decrease in the study areas. To further
test this, a trend analysis of a reconstructed annual runoff time series under undisturbed conditions has
been done. The results showed that in some sub-watersheds, although rainfall series had no significant
decreasing trend, the runoff series had significant downward trend. This can be explained by the nonlinear
relationship between rainfall and runoff. This study came to a different conclusion from the common
view, which observes that runoff decrease is mainly caused by land surface change if rainfall series lacks
a significantly decreasing trend. |
| Language: | English |
| Keywords: | runoff change; SWAT model; climate change; land surface use |