H1 2026 Evaluation
Belgium Reservoir Transparency
F31Opaque — Ranked #85 out of 167 countries
weight 30%
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weight 15%
weight 13%
weight 10%
weight 8%
weight 5%
Primary source evaluated
L'Hydrométrie en Wallonie (SPW/DGH) + waterinfo.be (VMM/HIC)
https://hydrometrie.wallonie.beDimension breakdown
Data Availability
20% of total score
Belgium has no single national portal for reservoir storage. Wallonia's hydrometrie.wallonie.be covers water levels and flows at 400+ stations via the WACONDAH network, but the publicly documented download interface (AQUALIM) explicitly covers only non-navigable rivers, not dam-reservoir storage volumes. The five major Walloon reservoirs (Eupen/Vesdre 25 hm³, Gileppe 26.4 hm³, Eau d'Heure complex, Nisramont 3 hm³, Ry de Rome) have no dedicated public storage dashboard. In Flanders, waterinfo.vlaanderen.be shows fill levels of flood retention basins (wachtbekkens), but these are flood control basins, not drinking water supply reservoirs. The Kluizen spaarbekken (10.9 hm³, De Watergroep) has no public real-time data. There is no national-level aggregate reservoir storage indicator.
Technical Accessibility
15% of total score
Both major regional portals have documented KIWIS-based REST APIs. Wallonia exposes hydrometrie.wallonie.be/services/KiWIS/KiWIS; Flanders uses download.waterinfo.be/tsmdownload/KiWIS/KiWIS (VMM) and www.waterinfo.be/tsmhic/KiWIS/KiWIS (HIC). R (wateRinfo) and Python (pywaterinfo) client libraries are maintained and peer-reviewed (rOpenSci). However, the APIs require credit tokens for bulk downloads, reservoir-specific storage volume parameters are not documented as standard API variables, and the Wallonia data download system requires form submission with data sent by email rather than direct API pull. AQUALIM data is available in Excel only.
Coverage
30% of total score
Belgium has only approximately 7 significant reservoirs, all in Wallonia. Combined capacity is roughly 90–130 hm³ total (Eupen 25 hm³, Gileppe 26.4 hm³, Eau d'Heure complex ~60 hm³, Robertville ~7 hm³, Bütgenbach ~11 hm³). FANC/SPW internally monitor the strategic Walloon drinking-water reservoirs but do not expose per-reservoir storage percentages publicly; smaller dams and Flemish facilities (Kluizen spaarbekken 10.9 hm³, privately managed by De Watergroep) are entirely absent from public reporting. Score lowered from 20 to 18 to reflect that the strategic-facility partial visibility is offset by the absence of smaller reservoirs and the lack of a public dashboard for any individual reservoir.
Historical Depth
13% of total score
AQUALIM (Wallonia, non-navigable rivers) has data going back to 1967, with a modern digitized format from 1999 onward. The hydrometrie.wallonie.be portal allows downloads but caps at 250,000 data points per request (~2 years at 5-minute resolution). Waterinfo.be (Flanders) covers at minimum several years of data. However, these historical depths apply to river gauge data, not specifically reservoir storage volumes. No confirmed historical time series for reservoir fill rates or storage volumes has been found publicly available.
Update Frequency
10% of total score
The WACONDAH system collects data at 1-minute or 5-minute intervals from hydraulic structures including dam-reservoirs. The Flanders 'wachtbekkens' status page shows near-real-time fill levels. AQUALIM river stations update every 10 minutes with hourly aggregation in the database. If reservoir-level data were publicly exposed, the underlying infrastructure clearly supports daily or sub-daily frequency. The score is limited because public access to reservoir-specific storage data is not confirmed at a daily granularity.
Methodological Transparency
8% of total score
Wallonia's Géoportail publishes INSPIRE-compliant metadata records for its AQUALIM network (station coordinates, measurement methods, temporal coverage). Capacity figures for major Belgian dams are available via infrastructure.wallonie.be (e.g. Eupen 25 hm³, Gileppe 26.4 hm³). However, no publicly available metadata specifically describes how dam-reservoir storage volume is calculated from water level, what stage-volume curves are used, or what measurement uncertainty applies. Station-level metadata is available for river gauges but not confirmed for reservoir storage specifically.
Language and Usability
5% of total score
Waterinfo.be (Flanders) is available in Dutch and English — the helpdesk and key pages have an English version (?KL=en parameter), and documentation for the wateRinfo/pywaterinfo APIs is fully in English. The Wallonia hydrometrie.wallonie.be portal is French-only with no confirmed English translation. Given the country's linguistic split, Dutch and French are primary, English is only partially available via the Flemish portal.
Evaluator notes
Belgium presents a fragmented picture: it is a small country with limited reservoir infrastructure (approximately 7 significant reservoirs, all in Wallonia, with combined capacity ~100–130 hm³) and a complex regional governance structure that splits water management between Flanders (VMM/HIC via waterinfo.be) and Wallonia (SPW/DGH via hydrometrie.wallonie.be). Both regions operate technically capable KIWIS-based hydrometric monitoring systems with documented REST APIs and multi-decade data archives, and the underlying measurement networks do instrument major dam-reservoir hydraulic structures at sub-hourly frequency. However, neither region exposes dam-reservoir storage volumes or fill percentages as a clearly labelled, publicly accessible, dedicated data product — the gap is at the public-dissemination layer, not at the sensor layer. The Flanders waterinfo.be portal is the more transparent of the two: it publishes real-time fill status for flood retention basins (wachtbekkens), has full English documentation, and its KIWIS API is wrapped in well-maintained open-source R and Python libraries published through rOpenSci. The Wallonia hydrometrie.wallonie.be portal is French-only, requires email-based form submission for bulk downloads, and the AQUALIM download interface formally covers only non-navigable rivers. The five major Walloon drinking-water supply reservoirs (Eupen, Gileppe, Eau d'Heure, Nisramont, Ry de Rome) do not appear to have individually accessible public storage dashboards, despite the SPW Direction des Barrages-réservoirs internally monitoring them. Belgium's low reservoir count and the absence of a national-level aggregate or per-reservoir public storage portal keep its RTI scores low despite technically advanced monitoring infrastructure. The Flanders 'wachtbekkens' that are publicly monitored are flood control basins, not drinking water reservoirs, which further reduces the relevance of available open data to water supply transparency. A meaningful RTI improvement would require Wallonia's SPW to expose per-reservoir storage percentages through hydrometrie.wallonie.be, similar to Spain's MITECO embalses portal.
Evaluated by Jaime Delgado · 2026-09-15 · Methodology v1.3.0