Persistent drought can have negative effects in many areas. Agriculture, shipping, the ecosystem in watercourses and wet nature areas, industry, and even energy supply and drinking water supply can run into problems during a long dry period.

Coordination during drought

The Coördinatiecommissie Integraal Waterbeleid (CIW, Coordination Committee for Integrated Water Policy) compiles an overall picture of the situation regarding drought, its impact on different sectors, and the measures to reduce negative impacts. You can consult this situation at opdehoogtevandroogte.be.

A general framework for taking measures during drought was laid down in the Vlaams Reactief Afwegingskader Droogte (VRAG). An overview of the current measures related to drought can be found at vlaanderen.be/droogtemaatregelen.

Drought monitoring

Drought and water scarcity are complex and multi-faceted problems. Various organisations in Flanders and Belgium developed specific drought indicators to track drought status and the (potential) impact of drought within a sector.

On waterinfo, the meteorological and hydrological aspects of drought are mainly shown:

• a map view of discharges at locations where gauging stations are suitable for accurately measuring low flows as well. Both current and forecast data are shown;
• an indication of low flows at monitoring locations by displaying low-water status, based on percentiles of historical measurement data, for non-navigable and navigable watercourses;
• the “Standardized Precipitation Index” (SPI) current and forecast with an accumulation period of 3 months (SPI‑3), showing how total precipitation over the past 3 months (90 days) compares to total precipitation in the same period of the year over 1991–2020 (source: RMI);
• the current “Standardized Precipitation Evapotranspiration Index” (SPEI) (waterinfo, item=droogte/actueel) with an accumulation period of 3 months (SPEI‑3), showing how the water balance (precipitation – evaporation) over the past 3 months (90 days) compares to the water balance in the same period of the year over 1991–2020 (source: RMI);
• tables with the currently measured precipitation deficit: the cumulative daily water balance (precipitation – evaporation);
• in addition, drought also has a direct and indirect impact—often in combination with heat—on water quality due to increasing water temperatures, increasing salinisation (conductivity), and decreasing oxygen concentrations. Water quality data can be found under the water quality theme.

 Additional data and an interpretation of drought conditions are published monthly in the report “Toestand van het Watersysteem” prepared by VMM. For navigable waterways, from April to September—or as the situation requires—an overview is produced by HIC in the “Laagwaterberichten” (low-water bulletins), and in case of drought also in drought bulletins. These bulletins can be consulted under the Rapporten.

Various organisations in Flanders and Belgium publish information on the status and impact of drought across different sectors.

• The meteorological drought status as determined by KMI/IRM can be found on RMI’s drought page.
• More details on groundwater conditions can be found via the Current Groundwater Level Indicator (DOV).
• Drought can contribute to the occurrence of toxic blue-green algae (cyanobacteria). An overview of blue-green algae observations is available on the following pages:
  • non-navigable watercourses: VMM website
  • navigable waterways: DVW website
• More information about salinisation in the coastal polders is available via the VMM salinisation dashboard.
• The current status of tap water supply can be found on the VMM tap water supply status indicator page.