Tunisia Reservoir Transparency

For the COVERED subset (all 36 large dams), ONAGRI publishes daily per-dam stock volumes (Mm³), fill percentages, daily inflows (apports) and releases (lâchers) through both the 'Situation journalière des barrages' PDF bulletin and the agridata.tn CKAN dataset. Daily granularity for >95% of the covered estate places this in the top band. The bulletin includes year-over-year comparisons and cumulative monthly/annual totals.

The agridata.tn portal is built on CKAN and exposes a standard REST API (api/3/action/datastore_search) for the barrages dataset, enabling programmatic row-level queries and CSV/JSON/XML downloads without authentication. This is a documented API plus structured downloads (open license) for the covered subset. The CKAN API requires knowledge of the internal resource UUID and no OpenAPI spec exists, which prevents a top-band score. ONAGRI's daily PDF mirrors are a secondary channel.

Conservative estimate — denominator includes ~230 hill dams (barrages collinaires) and ~950 hill lakes (lacs collinaires) which contribute roughly 20-25% of mobilisable water capacity nationally and are NOT in the ONAGRI daily bulletin (individually small but cumulatively non-trivial), plus small private agricultural and industrial impoundments. Methodology v1.3.0 (capacity-weighted). Covered capacity through the ONAGRI daily bulletin and agridata.tn CKAN dataset is the full ~2,700 hm³ of the 36-dam large-reservoir portfolio. A realistic national denominator that adds the conservative aggregate of small irrigation lakes and hill dams reaches approximately 3,000 hm³. Score = round(100 × 2,700 / 3,000) = 90. The 36 strategic large dams are fully publicly reported daily; the conservative discount reflects the small but real long tail of distributed small irrigation storage.

Median historical depth across the 36 covered dams is approximately 6-8 years. ONAGRI's archive of daily PDF bulletins is accessible back to at least January 2019 for the full estate (confirmed: 30-1-2019.pdf, 7-12-2019.pdf), and the agridata.tn CKAN dataset appears to cover from approximately 2018 onwards. Median falls in the 5-10 year band (60-79). Older per-dam records exist in DGBGTH/ONAGRI internal archives and academic literature for the largest reservoirs (Sidi Salem since 1981) but are not in a publicly accessible machine-readable form for the typical covered dam.

Daily refresh for >50% of the covered subset (in fact for all 36). The primary dataset is explicitly labelled 'Situation journalière' and ONAGRI publishes individual dated PDF bulletins for each day (naming convention: BARRAGES-DD-MM-YYYY.pdf). The agridata.tn dataset description confirms daily updates. ONAGRI's website displays a live aggregate stock figure as of the previous day. Among the highest update frequencies observed in MENA dam transparency.

Capacity figures for major dams are available through academic literature, ONAGRI annual water sector reports and the agridata.tn portal. DGBGTH conducts periodic bathymetric surveys for siltation and capacity reassessment (a 2006 Sidi Salem survey is cited in engineering literature). However, no publicly accessible consolidated methodology document explains how daily stock volumes are measured (gauge stations, telemetry networks, interpolation methods), how siltation corrections are applied, or where the hydrometric station network specifications are published. The CKAN dataset lacks a data dictionary.

The agridata.tn portal is available in French and Arabic only — no English interface. The ONAGRI website (onagri.nat.tn) is in French and Arabic. CKAN dataset metadata (field names, descriptions) is in French. Daily PDF bulletins are bilingual French/Arabic. The sole English-language access is through annual water sector executive summaries published by ONAGRI (2021 and 2023 editions in English), which provide aggregate national statistics but not per-dam time-series.