Planning Rooftop Rainwater Harvesting under Climate and Groundwater Uncertainty: An Integrated Decision Framework for Supplementary Urban Water Supply

Abstract

This repository contains the Supplemental Material accompanying the research manuscript entitled "Planning Rooftop Rainwater Harvesting under Climate and Groundwater Uncertainty: An Integrated Decision Framework for Supplementary Urban Water Supply." The study develops an integrated hydrologic-engineering screening framework for assessing rooftop rainwater harvesting (RWHS) as a supplementary urban water-supply option in Sylhet, Bangladesh. The framework considers climate-model reliability, future rainfall changes, groundwater trends, stored-rainwater quality, and life-cycle economics. Contents of the Supplemental Material S1. Purpose and Scope: Scope of the supporting analyses and documentation. S2. Climate-Data Workflow and Bias Correction: CMIP6 rainfall processing, linear scaling (LS), empirical quantile mapping (EQM), quantile delta mapping (QDM), nested bias correction (NBC), and temporally blocked cross-validation. S3. Future Rainfall Diagnostics: Seasonal rainfall changes under SSP2-4.5 and SSP5-8.5. S4. Groundwater Diagnostics: Supporting rainfall–groundwater comparisons and interpretation of groundwater trends. S5. Water-Quality Methods and Diagnostics: Rainwater collection, storage, sampling, laboratory analytical procedures, and quality-control information. S6. Economic Assumptions and Sensitivity: Life-cycle cost formulations, economic input assumptions, and sensitivity analysis. The accompanying document includes 18 supplemental equations (S1–S18), six supplemental figures (S1–S6), and three supplemental tables (S1–S3). These materials provide supporting methodological documentation and supplementary results. Findings should be interpreted together with the assumptions, uncertainties, and limitations presented in the associated manuscript. The supplemental material does not independently establish daily RWHS supply reliability, year-round potable-water safety, or causal groundwater recovery. Associated Manuscript: Planning Rooftop Rainwater Harvesting under Climate and Groundwater Uncertainty: An Integrated Decision Framework for Supplementary Urban Water Supply. Authors: Gour Dhan Barman, Ahmad Hasan Nury, Radif Raiyan Emon, Gulam Md. Munna, and Khairul Hasan. Institution: Department of Civil and Environmental Engineering, Shahjalal University of Science and Technology, Sylhet, Bangladesh. Funding: SUST Research Centre, Shahjalal University of Science and Technology, Bangladesh.