Senegal Reservoir Transparency

Manantali reservoir water level (cote in m IGN) is published publicly on mha.gouv.sn during the flood season as part of daily hydrological bulletins (documented examples: 208.38 m IGN on 19 Sep 2025, 208.14 m IGN on 27 Oct 2025). Diama dam level is also included. However, storage volume — the most operationally relevant indicator — is never published; only the elevation cote is given. Lac de Guiers, Senegal's main domestic water supply reservoir, has no public storage or level data. Publication is seasonal (July–October) and event-driven, not continuous. Outside flood season, essentially no current operational reservoir data is publicly accessible.

All published hydrological data is delivered exclusively as PDF documents or narrative HTML blog posts on mha.gouv.sn. No REST API, no structured file formats (CSV, JSON, XML), and no bulk-download mechanism exists. OMVS transmits monitoring data by satellite internally (to SOGEM, SOGED, and national capitals) but does not expose this feed publicly. The PROGRES database (DGPRE) is described as internet-accessible but covers hydraulic structure inventory rather than operational time-series; direct-download access for researchers reportedly requires a formal request to DGPRE. No registration-free machine-readable access to reservoir data was found.

v1.3.0 capacity-weighted: coverage = round(100 × covered_capacity_hm³ / total_national_capacity_hm³). Senegal's total reservoir capacity above 10 hm³ is approximately 12,000 Mm³, dominated by the shared OMVS reservoir Manantali (~11,300 Mm³, ~94% of national capacity), with Diama (~250 Mm³), Lac de Guiers (~500 Mm³), and small Anambé/Niandouba (~85 Mm³ combined). MHA/OMVS bulletins routinely cover Manantali (level in cote IGN) during the flood season plus occasional Diama coverage, capturing approximately 11,300 Mm³ of qualifying storage. Coverage = round(100 × 11,300 / 12,000) = 94. The capacity-weighted view sharply raises the score because Manantali holds the overwhelming majority of national storage and is publicly tracked (elevation only, seasonally) by OMVS/MHA. Lac de Guiers (Dakar supply) and the small irrigation reservoirs remain uncovered but contribute only a marginal share of total capacity.

The mha.gouv.sn reports archive shows bulletins dating back to 2024 at most; no publicly accessible hydrological bulletin archive predating 2024 was found through the website. The OMVS documentation centre historically stored data in paper form only. The PROGRES database contains long-term hydraulic structure records but is not publicly downloadable as a time series; academic papers cite receiving DGPRE discharge data for Bakel station covering 2011–2020 only through formal institutional channels. No machine-readable multi-year reservoir storage history is accessible to the public.

During the rainy and flood season (roughly August–October), MHA/DGPRE publishes hydrological situation bulletins at near-daily frequency, sometimes twice per day when alert levels are high. Outside this period, publication drops to infrequent or zero; no evidence was found of year-round systematic reservoir level reporting. The bulletin series is labeled 'Communiqué de Presse N° 01' in August, suggesting it begins fresh each season rather than maintaining a continuous record. OMVS also publishes an irregular series of bulletins hydrologiques. This seasonal cadence is better than many peers but falls short of year-round operational transparency.

Bulletins reference measurements in 'cote IGN' (elevation above Institut Géographique National datum), which implies a standard reference system, but no public methodology document describes gauge instrumentation, calibration procedures, uncertainty ranges, or how elevation readings translate to storage volumes. OMVS operates a satellite-linked monitoring network covering multiple stations, but its technical specifications are not published. The flood alert plan PDFs (four country-specific documents) cover threshold definitions for emergency response but not hydrometric measurement methodology. No quality assurance or uncertainty documentation was located.

All official publications — MHA bulletins, OMVS bulletins, DGPRE reports, PROGRES database — are exclusively in French. No English-language versions, summaries, or translations of operational data were found on any official Senegalese or OMVS platform. This is unsurprising given French is the sole official language, but it creates a complete barrier for non-Francophone users and reduces international usability to near zero.