Impact of landscape dams on river water cycle in urban and peri-urban areas in the Shiyang River Basin: Evidence obtained from hydrogen and oxygen isotopes

• Published in: Journal of hydrology (Amsterdam) 2021-11, Vol.602, p.126779, Article 126779
• Main Authors: Zhu, Guofeng, Sang, Liyuan, Zhang, Zhuanxia, Sun, Zhigang, Ma, Huiying, Liu, Yuwei, Zhao, Kailiang, Wang, Lei, Guo, Huiwen
• Format: Article
• Language: English
• Subjects: Arid regions; Stable isotope; Urban landscape dams; Water cycle
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2021.126779

•Landscape dams increase the evaporation loss ratio by 0–5%.•Landscape dams have greatly impact the local precipitation and groundwater.•The cumulative effect of landscape dams has a great impact on local water cycle. To meet the needs of human recreation and provide community amenities, landscape dams (i.e., water retaining structures for intercepting river water in cities and surrounding areas, which are mainly used to create an urban landscape environment) are built in urban and peri-urban areas worldwide. The construction of these dams, however, may adversely affect the local and regional water cycle. We collected water samples from 2015 to 2019 from different water bodies in urban and peri-urban areas traversing the middle and upper reaches of Shiyang River Basin in the arid area of Central Asia to analyze their isotopic characteristics. Meanwhile, field surveys as well as meteorological, hydrological, and remote-sensing data were added to evaluate the hydrologic effects of urban landscape dams on a watershed scale in an arid region with scarce water resources and fragile ecosystems. Isotopic values of landscape water were more enriched than that of natural river. The result of the evaporation loss ratio showed that the landscape water was 0–5% higher. Moreover, the cumulative effect of multiple landscape dams leads to a great loss of water resources in arid areas. The study also demonstrated that evaporation is a vital factor in causing change in the isotope composition of the landscape water in the Shiyang River Basin. The interaction between surface water and groundwater was frequent within the landscape dam area wherein groundwater was mainly recharged by surface water leakage. Sufficient attention should be given to the evaporation, leakage, local precipitation, and groundwater changes caused by the impoundment of landscape dams. Thus, the potentially adverse effects of urban landscape dams in arid regions should be highly considered in long-term water-resources sustainability planning.