Mali Reservoir Transparency

Manantali (11,300 Mm³, ~96% of Mali's tracked reservoir capacity) is monitored by OMVS, which publishes near-daily hydrological bulletins during the rainy season reporting reservoir level in metres IGN (e.g. 208.38 m IGN on 2025-09-19, 208.14 m on 2025-10-27). These are publicly accessible on the OMVS website and re-published by Senegal's DGPRE/MHA. Sélingué (2,170 Mm³) has no current-storage figure published by EDM or DNH; the DNH SINEAU system lists a 'Barrage/Hydro-électricité' section but its public interface shows only actor directories, not operational data. No Mali government agency publishes a current storage volume directly. Data exists but is fragmented across a multinational body (not Mali's own government), covers water level rather than volumetric storage, and omits Sélingué entirely.

No REST API exists at any identified source. OMVS bulletins are published as narrative web pages (HTML) or PDF documents in French only; no CSV, JSON, or other machine-readable format is available for download. The DNH SINEAU public interface provides HTML tables of actor contacts, not data exports. The ABN Niger-HYCOS portal (nigerhycos.abn.ne) offers anonymous access to Niger River gauge data for several Mali stations (Akka, Kenieroba, Kirango Aval, Bani à Kana) and could be queried via URL parameters, but it is functionally unavailable (connection errors during evaluation) and covers river gauges, not reservoir storage. No registration-free structured data endpoint was found for any Mali reservoir.

v1.3.0 capacity-weighted with conservative estimation applied 2026-05-29. Mali total national reservoir storage capacity ~17,300 hm³ across 4–5 reservoirs above 10 hm³: Manantali (~11,300 hm³, OMVS), Sélingué (~2,170 hm³, EDM), Sotuba, plus the Markala/Office du Niger regulating works and smaller irrigation reservoirs. COVERED capacity ≈ 9,500 hm³ on a conservative basis via OMVS near-daily hydrological bulletins for Manantali during the rainy season (level in m IGN) published on omvs.org and re-published by Senegal's DGPRE/MHA. Coverage = round(100 × 9,500 / 17,300) = 55. The conservative downward revision from 65 reflects that Sélingué (~2,170 hm³) has zero public reporting (EDM publishes nothing operational), that OMVS bulletins are seasonal (concentrated July–October with dry-season silence), that the published metric is level rather than full storage volume, and that DNH SINEAU exposes only actor directories without storage exports.

OMVS maintains the HYDRACCESS database with records for Senegal River basin stations going back to 1904, and calibration curves were established for stations between 1997–2000 and updated in 2012. However, this archive is not publicly downloadable: the OMVS website offers only institutional reports and PDF bulletins, not the underlying time-series data. The Niger-HYCOS portal claimed multi-year hydrograph access for Mali Niger River stations but was unreachable during evaluation. Academic literature (Springer, IntechOpen) references the long record for research purposes but not as public data. For Sélingué, no historical archive of any kind is accessible online. Effective publicly accessible machine-readable historical depth is near zero despite an internally rich institutional archive.

During the rainy season (July–October) OMVS and Senegal's DGPRE publish Manantali water level data daily or near-daily, as evidenced by bulletins on consecutive days in September 2025. Outside the flood season publication cadence drops sharply; no dry-season bulletin series was found. No automated data feed or real-time sensor endpoint is public. Sélingué data is never updated publicly. The seasonal concentration of updates limits the annual average update frequency significantly.

OMVS references a network of over 40 limnimetric stations, the HYDRACCESS database, and the SIMULSEN simulation software in technical documents, and station calibration curves are mentioned in peer-reviewed literature (Springer 2020). However, no public methodology page exists on omvs.org explaining measurement instruments, rating curve derivation, quality-control procedures, or uncertainty estimates for Manantali data. OMVS bulletins report water level in metres IGN with no accompanying methodological note. DNH and EDM publish no methodology whatsoever. The HYCOS project document (2012 PDF) describes intended observational infrastructure but not operational protocols.

French is Mali's sole official language and all primary sources (OMVS bulletins, DNH SINEAU, EDM website, ABN website) are exclusively in French. OMVS.org has no English toggle. The ABN Niger-HYCOS portal has an English-language flag option but the portal was unreachable during evaluation and the interface is primarily French. No English-language official data publication from any Malian or OMVS source was found. Researchers accessing data must be French-literate. The score of 8 reflects minimal inherent English accessibility: UNESCO and World Bank aggregate some figures in English, but those are not primary operational sources.