Modeling the Impact of Land Use Changes and Wastewater Treatment on Water Quality and Ecosystem Services in the Yongding River Basin, North China.

Rapid socioeconomic development, urbanization, agricultural activities, and infrastructure development can greatly alter natural landscapes and their environmental impacts. Understanding these changes is crucial for more sustainable, integrated land management, including addressing water-related environmental challenges. In this study, we explored the impacts of two key factors on water quality and ecosystem services (ESs): land use change and the expansion of wastewater treatment (WWT) infrastructure by combining cellular automata Markov (CAM), water quality and environmental valuation modeling, and statistical analyses. We examined historic land use changes and forecasted their future evolution. The impacts were assessed by analyzing the spatial and temporal distribution of major water pollutants, water quality trends, and the economic valuation of ESs under real WWT expansion conditions, assessing a Chinese policy in effect. The Yongding River Basin in North China was selected as a case study due to significant urbanization and WWT changes over the past decades under arid conditions. The results indicate that pollutant loads were highest in urban areas, followed by rural areas, and that domestic WWT efficiency is a dominant factor in the spatial pattern of pollutant discharge. ES values decrease in the short term but can increase in the long term with WWT expansion, owing to the planned ecosystem restoration policy. This study provides valuable insights into the responses of water pollution and ESs to land use changes over spatiotemporal scales, encouraging the consideration of these factors in future land and infrastructure planning. [ABSTRACT FROM AUTHOR]