<p>The success of urban river rehabilitation depends not only on ecological outcomes but also on public acceptance and engagement, yet most riparian assessment tools rely on ecological and physicochemical criteria while overlooking how local communities perceive and value their rivers. Incorporating social indicators that reflect what people see, perceive, and value is therefore essential for designing interventions that are both ecologically sound and socially legitimate. This study aimed to identify and define social dimensions of urban riparian quality and to integrate them into a composite socio-environmental quality index. A series of participatory workshops was conducted with students from the Ezequiel Demonty Bachillerato Popular, a self-managed educational initiative located adjacent to the highly degraded Matanza-Riachuelo River (Buenos Aires, Argentina), whose students are adult residents of the surrounding territory. Through diverse activities including drawings, collages, and narratives, the workshops explored how students perceive and evaluate the river and its banks, and what they envision as a desirable future riverscape. Five key social dimensions of environmental quality emerged: cleanness and care, biological integrity, visual appeal, safety, and recreational opportunities. These dimensions were integrated into a proposed Pampean Riparian Socio-Environmental Quality Index (ICSRP), which combines traditional ecological and physicochemical criteria with community-derived social dimensions. A Discrepancy Index (DI) is also proposed to quantify the alignment between technical and social assessments. This work offers a methodological contribution toward more inclusive and context-sensitive tools for urban riparian quality assessment.</p> Graphical abstract <p></p>