Mutual promotion relationship of ecological base flow and basin wetland restoration in arid areas

Abstract

Climate change and human activities are continuously affecting global environmental change, causing severe damage to rivers and watersheds wetland ecosystems in arid areas. However, the interaction between ecological base flow (EBF) in rivers and wetland restoration (WR) in watersheds remain poorly understood. In this study, we analysed the changing characteristics of EBF and WR in the Niya River Basin in Xinjiang, a typical arid area, as well as the interaction between the two. The results showed that the EBF of the Niya River increased slowly at an annual rate of 0.241 m³ s⁻¹ • (10a)⁻¹ from 1978 to 2022, with significant seasonal changes throughout the year, and the proportion during the normal flow periods reached 97.9 %. The WR in the basin also showed the same change trend, the wetland area and fractional vegetation cover (FVC) in the basin increased annually, and the groundwater level (GWL) had a seasonal variation of 1 m to 4 m with precipitation. However, the species composition in the wetland was relatively thin, and the structural function had to be improved. The intra-annual correlations between EBF and GWL and between EBF and FVC were 0.884 and 0.729, respectively. There was a positive mutual promotion relationship between EBF and WR in the watershed, the guarantee or increase of EBF can provide sufficient water resources for the growth of plants and animals in wetlands, and maintain the stability of wetland ecological environment to promote WR. The WR can increase river runoff by promoting water circulation and other means, ensuring that EBF is continuously met, thereby improving the health and stability of river ecosystems. Our study could provide valuable insights for guaranteeing the EBF of rivers in arid areas, protecting and restoring wetlands, and managing and scheduling water resources.