OE1. 5 Participatory DPSIR analysis of informal settlement wastewater impacts on water supply hydrological services

Abstract

Informal settlements (IS) growth threatens water supply hydrological services (WSHS) due to the discharge of untreated wastewater to receiving bodies. The impact of untreated wastewater from IS on water quality is documented. However, most research focuses on partial components of the socio-environmental cycle and does not holistically integrate the social, economic, technical, environmental, and governance dimensions of water. This paper proposes a tool comprising a conceptual model based on the Drivers, Pressure, State, Impact, and Response (DPSIR) framework for participatory analysis of the impact of wastewater on WSHS and the identification of intervention strategies. The model involved 196 indicators from different dimensions and 12 participatory data collection instruments including surveys, interviews, inspections and water quality monitoring in both dry and rainy season. The tool was validated in a case study in three IS, showing its feasibility, convenience, and usefulness. Field validation revealed a decrease in the Water Quality Index (WQI) associated with the discharge of wastewater from IS (ΔWQI = − 0.06, 95% confidence interval: [− 0.012, − 0.124], with a baseline of 0.68 before the discharge, equivalent to a relative reduction in water quality of 9%). The tool can support practitioners in designing comprehensive and participatory interventions to address the pressing issue of IS wastewater pollution in developing countries, thereby contributing to the goal of sustainable cities. In addition, the tool fills a gap in the implementation of the DPSIR framework for wastewater management, focusing on IS and integrating robust participatory approaches.