Telecoupled impacts of Yudiba Dam on reforestation in the Loess Hill Ravine Region of northern Shaanxi

Abstract: As a large-scale check dam, Yudiba Dam on the Loess Plateau of China, is a kind of check dam with the height more than 5 m which is used to retain soil and water, produce grain and control flood. The Yudiba dam plays an important role for vegetation restoration in the process of returning cropland to forest in the Loess Hill Ravine Region of northern Shaanxi. This study explores the telecoupling relationship between the check dam in Yulin, and the vegetation reforestation in the local and adjacent areas based on the statistical yearbook data and remote sensing data of the northern Shaanxi from 2000 to 2020. The results show that: (1) The normalized vegetation index (NDVI) of Yulin, Shaanxi Province, shows an increasing trend during 2001-2015. The NDVI is higher in the east of northern Shaanxi, Yulin, where the check dams are more concentrated, and shows a decreasing pattern in the west of northern Shaanxi where the check dams are more dispersed. The NDVIs of Mizhi, Suide and Qingjian counties in the east are 0.510, 0.511 and 0.520, respectively. The NDVI of Dingbian County in the west is only 0.354, while the NDVIs of Zizhou and Hengshan counties which are closer to the east, are 0.414 and 0.390, respectively. This indicates that the construction of Yudiba dam in Yulin significantly contributed to the growth of vegetation cover in local and other surrounding regions of Yulin. (2) Driven by the policy of returning cropland to forest in Shaanxi Province, the construction of Yudiba dam in the west of northern Shaanxi, e.g. Dingbian county, may be also strengthened because of the need of vegetation restoration. The construction of Yudiba dam will promote the infertile slope farmlands to be replaced with high-productivity check-dam farmlands in the west of northern Shaanxi. Hence the construction of Yudiba dam in Yulin may be helpful in realizing sustainable development of resource and environment in northern Shaanxi Province.

Keywords: Telecoupling, Yudiba dam, sloping farmland, vegetation restoration, returning cropland to forest