Effects of land use/land cover and climate changes on surface runoff in a semi-humid and semi-arid transition zone in northwest China
Water resources, which are considerably affected by land use/land cover (LULC) and climate changes, are a key limiting factor in highly vulnerable ecosystems in arid and semi-arid regions. The impacts of LULC and climate changes on water resources must be assessed in these areas. However, conflictin...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-01-01
|
| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/21/183/2017/hess-21-183-2017.pdf |
| Summary: | Water resources, which are considerably affected by land use/land cover
(LULC) and climate changes, are a key limiting factor in highly vulnerable
ecosystems in arid and semi-arid regions. The impacts of LULC and climate
changes on water resources must be assessed in these areas. However,
conflicting results regarding the effects of LULC and climate changes on
runoff have been reported in relatively large basins, such as the Jinghe
River basin (JRB), which is a typical catchment
(> 45 000 km<sup>2</sup>) located in a semi-humid and arid transition
zone on the central Loess Plateau, northwest China. In this study, we focused
on quantifying both the combined and isolated impacts of LULC and climate
changes on surface runoff. We hypothesized that under climatic warming and
drying conditions, LULC changes, which are primarily caused by intensive
human activities such as the Grain for Green Program, will considerably alter
runoff in the JRB. The Soil and Water Assessment Tool (SWAT) was adopted to
perform simulations. The simulated results indicated that although runoff
increased very little between the 1970s and the 2000s due to the combined
effects of LULC and climate changes, LULC and climate changes affected
surface runoff differently in each decade, e.g., runoff increased with
increased precipitation between the 1970s and the 1980s (precipitation
contributed to 88 % of the runoff increase). Thereafter, runoff decreased
and was increasingly influenced by LULC changes, which contributed to
44 % of the runoff changes between the 1980s and 1990s and 71 % of
the runoff changes between the 1990s and 2000s. Our findings revealed that
large-scale LULC under the Grain for Green Program has had an important
effect on the hydrological cycle since the late 1990s. Additionally, the
conflicting findings regarding the effects of LULC and climate changes on
runoff in relatively large basins are likely caused by uncertainties in
hydrological simulations. |
|---|---|
| ISSN: | 1027-5606 1607-7938 |