Integrating human–stream interactions into ecological stream assessment: A novel rural–urban socioecological sustainability framework

Current assessment tools for streams and rivers focus on ecological functioning while ignoring the social dimension, which varies across rural and urban ecosystems. This study presents the rural–urban socioecological stream sustainability index (hereinafter, RU-SESSI) for assessing stream function across the rural–urban continuum. This index is based on the stream ecosystem services (ES) and biodiversity index (SESBI), which was developed in our previous study to assess stream health. The SESBI was extended into a sustainability subindex by adding two economic indicators, and the framework was complemented by a stream–society interaction subindex comprising accessibility, public safety, and community involvement. Together, these subindices capture stream function through both sustainability performance and human–stream interaction patterns. The framework was refined and validated using the Delphi method, revealing significant differences in the relative importance of most RU-SESSI indicators between rural and urban segments. Applied to the Yarkon Stream in central Israel, the index revealed higher biodiversity and regulating services scores in the rural reach, whereas economic, recreation, and accessibility scores were higher in the urban reach, while public safety and community involvement were comparable between reaches. The urban reach achieved a slightly higher RU-SEES score than the rural reach (6.22 vs. 5.76), with no significant difference in the distribution of weighted indicator scores. The RU-SESSI offers a context-sensitive framework that accounts for unique socioecological dynamics, providing policymakers with valuable insights for tailoring stream management to rural–urban settings and contributing to global water security and sustainability.