Author(s): Guohua He, Yong Zhao, Jiaqi Zhai
Linked Author(s): Guohua He
Keywords: Normalized difference vegetation index, groundwater table depth, water-saving, ecosystem degradation
Abstract: Hetao is the largest irrigation area with water consumption in the Yellow River basin, which is also the biggest irrigation area in arid and semiarid regions of China. Due to severe water shortage, application of water-saving measures are required to relieve water use pressure. To assess the impact of water-saving practices on ecosystem degradation in Hetao, we investigated the relationship between vegetation and depth of the groundwater table by combining Normalized Difference Vegetation Index (NDVI) with in-situ groundwater observations and using Visual MODFLOW to evaluate the effect of water saving measures on water table depth (GWD). Research findings indicated that: (1) maintaining GWD at 2. 0-2. 5m on growing seasons is suitable for ecosystem security. (2) GWD declines progressively with the strengthening of water-saving practices, and more than forty percent of the land will end in the risk of ecological degradation if water efficiency ratio of canal system reach the standard of the local canal liming plan as 0. 66. Based on the results, a conclusion was drawn that water-saving practices with no limits in arid and semi-arid region could cause ecological damage, and this conclusion is strongly advised to be taken into consideration when stakeholders make water saving strategies in arid or semi-arid region
Year: 2017