lsj794222-stack/beledweyne-flood-ffm

SAR-based flood frequency mapping for Beledweyne, Somalia (Sustainability 2026) # Beledweyne Flood Frequency Mapping (2015-2025) SAR-based flood frequency mapping and policy impact analysis for **Beledweyne, Hiraan, Somalia** using 10 years (2015-2025) of Sentinel-1 GRD scenes, three independent detection algorithms, three DEMs, and BFAST change-point analysis around the 2020 forced relocation policy. This repository accompanies the manuscript: > *(Citation will be added after publication.)* ## Key results - **259 Sentinel-1 GRD VV** scenes processed (2015-01-12 to 2025-XX-XX, DESC orbit) - **3 flood detection methods** compared: Fixed (-17 dB), Z-score (<-2 sigma), Log-ratio (<-3 dB) - Z-score and Log-ratio methods agree (Pearson r = +0.68); the fixed threshold is dominated by SAR shadow and permanent water - **BFAST change-point** detection shows that 49.9 % of pixel-level breaks occur *after* the 2020 policy, vs 35.6 % before - Mean flooded fraction **increased by 19.8 %** from pre-policy (4.68 %) to post-policy (5.61 %); KS test D = 0.854, p ~= 0 ## Repository structure beledweyne-flood-ffm/ ├── notebooks/ 7 sequential analysis notebooks │ ├── 01_gee_acquisition.ipynb │ ├── 02_sar_preprocessing.ipynb │ ├── 03_flood_detection.ipynb │ ├── 04_ffm_validation.ipynb │ ├── 05_hand_dem.ipynb │ ├── 06_bfast_policy.ipynb │ └── 07_figures_tables.ipynb ├── src/ Reusable Python modules │ ├── config.py Central paths and constants │ ├── flood_methods.py 3 SAR flood detection algorithms │ ├── sar_utils.py SAR preprocessing helpers │ ├── ffm.py Flood Frequency Metric │ ├── hand.py HAND via pysheds │ ├── bfast.py BFAST changepoint + time series │ ├── gee_utils.py Google Earth Engine helpers │ └── viz.py Matplotlib helpers ├── data/ │ ├── external/ Raw inputs (gitignored - public mirrors) │ └── processed/ FFM, HAND, BFAST outputs (CC-BY 4.0) ├── tables/ Manuscript Tables 1-4 (CSV + MD) ├── figures/ Manuscript Figures 1-7 + S1 (PNG + PDF) ├── manuscript/ Workflow XML and supplementary ├── environment.yml Conda environment specification ├── .env.examp …