Mekong Delta water quality and hydrodynamic analysis package (1985–2022)

This repository contains the complete analysis environment (scripts, derived outputs, and all processed datasets) supporting the publication:

Nguyen, A. T., Nemery, J., Tran, K. T., Tran, T. T., Truong, T. V., Le, T. M. T., Nguyen-Dam, Q. H., & Garnier, J.: Weakened hydrodynamic flushing decouples organic pollution from discharge in the Mekong Delta, *Nature Water* (2026).

The public code repository (scripts without restricted data) is available at https://github.com/nguyentruonganlab/mekong-delta-water-quality.

Repository structure

scripts/— Python scripts for figure and table generation, and for statistical analyses (trend detection, changepoint analysis, C--Q scaling, WRTDS flow-normalization, fixed-effects regression, SHAP attribution, variance decomposition, and mass balance). The scripts use input data from the folder data and save outputs to manuscript/figures.

data/ — Input data and intermediate outputs required to reproduce the results and figures:

Harmonized water quality observations (MRC 1985–2022; Ben Tre DONRE 2005–2022)

Daily discharge and water-level records

Pre-computed station-year master tables (LULC, population, hydro-climate)

Fertilizer statistics and spatial reference layers

Large raw rasters (JAXA VLUCD, ERA5, CHIRPS, GlobPOP) are excluded due to size but are publicly available from the sources listed in the manuscript Data Availability statement.

analysis/ — Derived analysis outputs: changepoint statistics, fixed-effects regression coefficients, SHAP attributions, variance decompositions, mass-balance results, and WRTDS flow-normalization outputs.

manuscript/ — Publication figures (main text and extended data) and tables in PDF and PNG formats (600 DPI).

Citation requirement

When using materials from this repository, please reference both:

This repository (including the version used), and

The publication (Nguyen et al., 2026).

License & access

Analysis code, derived outputs, and figures are available under CC-BY-NC 4.0. Ben Tre provincial monitoring data (DONRE) and discharge and water-level data (SIWRP) follow organizational policies and are available upon request for non-commercial use. MRC water quality data are publicly available from the MRC Data Portal (https://portal.mrcmekong.org/).

Disclaimer

The data and code are provided "as is". While compiled with great care, no warranty is given regarding correctness or completeness.

Contact

For questions, please contact the corresponding author as listed in Nguyen et al. (2026).