Mozambique Reservoir Transparency

HCB's homepage displays a daily hydrological widget for Cahora Bassa (water level in m.a.s.l., inflow and outflow in m³/s, and meteorological readings), making it the only Mozambican operator with any routine public reservoir data. However, this display is a corporate homepage element, not a dedicated data portal, and presents no storage percentage or volumetric figure. For secondary dams — Massingir, Corumana, Pequenos Libombos, Chicamba — data reaches the public exclusively through ARA-Sul or DNGRH press releases and occasional ARA-Centro quarterly drought bulletins (PDF), not through any standing online interface. ARA-Sul's own website is explicitly under development and returns placeholder pages. No centralised national reservoir dashboard exists.

No REST API, no open data formats, and no bulk download are offered by any Mozambican government or operator source. HCB's hydrological widget is an embedded webpage element with no documented endpoint; historical navigation appears to use arrows on a web page rather than a queryable dataset. ARA-Centro quarterly bulletins are published as PDF documents — human-readable but not machine-readable. The DNGRH monitoring portal (monitoriaavaliacao.dngrh.gov.mz) was unreachable during evaluation. The only machine-accessible time-series for Cahora Bassa comes from the third-party DAHITI satellite altimetry database (TU Munich), which covers the reservoir from approximately 2002 onwards using multi-mission radar altimetry; DAHITI offers a Version 2 API but requires free registration and is an academic rather than an official national source.

v1.3.0 capacity-weighted: coverage = round(100 × covered_capacity_hm³ / total_national_capacity_hm³). Mozambique's total national reservoir capacity above the 10 hm³ threshold is approximately 57,000 Mm³, overwhelmingly dominated by Cahora Bassa (~52,000 Mm³, the operational figure HCB tracks daily — ~91% of national capacity). Secondary dams: Massingir (~2,800), Chicamba (~2,000), Corumana (~1,200), Pequenos Libombos (~390), plus a long tail of smaller dams. HCB publishes Cahora Bassa daily on its hidroelectricidade widget, covering ~52,000 Mm³ of qualifying storage. Coverage = round(100 × 52,000 / 57,000) = 91. The capacity-weighted view inverts the previous count-based picture: while only 1 of ~20 reservoirs has a standing public feed, that single reservoir holds the overwhelming majority of national storage. The remaining ~6,000 Mm³ across the secondary dam estate receives only intermittent ARA-Sul/ARA-Centro press coverage and is not classified as covered.

No official machine-readable historical archive of reservoir storage data has been identified for Mozambique. HCB's homepage widget includes previous/next date navigation but no publicly accessible download or archive URL. Quarterly ARA-Centro PDF bulletins provide snapshots back to at least 2024 but are not digitised into a continuous time series. Financial and operational metrics in HCB annual reports (storage percentages on 31 December each year) provide a handful of annual data points but are embedded in narrative documents, not structured datasets. The only accessible multi-year machine-readable time series is the DAHITI satellite altimetry record for Cahora Bassa, a third-party academic source covering approximately 2002–present.

HCB's hydrological widget appears to be updated daily — the data shown during evaluation was dated to a specific day (26 May 2024 in the cached version), and navigation arrows imply day-by-day records. This is a positive signal for Cahora Bassa. However, no update schedule is formally documented and the widget does not self-describe its cadence. For secondary dams, ARA-Centro publishes quarterly seasonal bulletins during the dry season, and ARA-Sul releases data only reactively via press statements during flood or drought events. There is no routine monthly or weekly national publication equivalent to South Africa's DWS weekly bulletin.

HCB uses quota (metres above mean sea level) converted to a percentage of useful storage volume; this method is inferable from published annual report data points (e.g. 305.20 m = 21.19% useful storage at Cahora Bassa), but no formal methodology document, measurement station specifications, or data quality protocol is published on the HCB or ARA-Sul websites. HCB holds ISO 9001:2015, ISO 14001:2015, and ISO 45001:2018 certifications, confirming structured management systems, and has undergone a Hydropower Sustainability Standard (HSS) assessment (published April–May 2026) that reviewed hydrological monitoring practices — but the underlying measurement specifications remain internal documents not available to the public.

Portuguese is the sole official language of Mozambique and all ARA, DNGRH, and ARA-Centro publications are exclusively in Portuguese. HCB maintains an English-language version of its website (hcb.co.mz/eng) and several sub-pages load in English, but the English version is partially implemented — some pages return 404 errors and the hydrological data widget appears only on the Portuguese homepage. The 2025 HSS sustainability assessment was published in both English and Portuguese, providing a notable but limited exception. No English-language data portal or bulletin exists for secondary dams.