| Regional sustainable development and socio-economic progress are inherently dependent on the effective delivery of ecological services provided by water conservancy projects. Quantifying the ecosystem service value (ESV) of regional water conservancy projects is essential for advancing water ecosystem conservation and environmental improvement, requiring multi-element valuation approaches that incorporate rigorous methodological selection, dynamic multi-factor coupling analysis, and the identification of regional characteristics. This study constructs a systematic valuation framework for the ESV of water conservancy projects, conducts an assessment of project impact, and proposes a method for quantifying the market value of water ecological products. From the perspective of land cover-function value matching, the InVEST model is utilized to quantify regional impact extent and module value, subsequently enhancing the ESV of water conservancy projects through systematic optimization methods. Based on a land use change matrix, spatial distribution maps of water conservancy project ESV for different periods are generated to explore their spatiotemporal variation characteristics and distribution patterns. The study results indicate that from 2000 to 2020, Langfang City experienced an increase in urbanized land area and a slight decrease in vegetation cover, with a dynamic index of -0.03%. Concurrently, the ESV of water conservancy projects showed an upward trend, increasing by 58.42%. The ESV of water conservancy projects exhibited a significant positive correlation with vegetation and water body areas, and a significant negative correlation with bare land area. Furthermore, socio-economic indicators related to Nature-based Solutions (NbS)-oriented eco-environmental industries and ecological restoration showed a correlation coefficient greater than 0.3 with the ESV, indicating a strong correlation. These findings can provide technical support for achieving regional water ecological security and the sustainable utilization of water and soil resources. |