How reservoirs help countries cope with dry periods: Spain compared with France, Germany, the Czech Republic and Austria.
When drought in Europe is discussed, Spain often features among the countries most exposed. However, climate risk and the capacity to respond to it are different issues. A country may receive less rainfall yet have infrastructure that enables it to retain some of that water for the months when it is needed most.
Spain has a specific advantage: an extensive network of dams and reservoirs built to manage irregular rainfall. A comparison with France illustrates how significant that capacity can be. This does not make Spain immune to drought, but it provides an important tool for reducing its consequences.
Infrastructure Built out of Necessity
Spain’s Ministry for the Ecological Transition, MITECO, identifies the country’s irregular water regime as one of the main historical reasons for building dams. Alternating dry periods and periods of abundant water create a need to store water and regulate its availability. According to the ministry’s overview, Spain has more than 1,200 large dams, with an approximate storage capacity of 56,000 cubic hectometres (hm³).
These reservoirs supply households, irrigated agriculture and industry, and support electricity generation. Their value lies in allowing some of the water available at one point in time to be used later, within each system’s operational capabilities and requirements.
Spain and France: a Significant Difference in Capacity
A French Senate report published in 2023 provides a particularly useful comparison: 54,000 hm³ of storage capacity in Spain, compared with 12,000 hm³ in France. On those figures, Spain’s capacity is approximately 4.5 times that of France.
| Country | Capacity |
|---|---|
| Spain | 54,000 hm³ |
| France | 12,000 hm³ |
These are capacity figures, not the amount of water currently stored or the volume available for consumption each year. They are presented as a comparison from the report, rather than a continuously updated inventory. The Spanish figure in that comparison and MITECO’s approximate figure come from different references and should not be treated as a single statistical series.
The finding is significant but specific: Spain has substantially greater reservoir storage capacity than France. It does not establish that all other European countries lack reserves, or that Spain is better prepared in every aspect of water management.
Germany, the Czech Republic and Austria: Three Further Comparisons
Extending the comparison reinforces the importance of Spain’s infrastructure, but requires a distinction between total volume, usable volume and the number of dams. National sources use different criteria and reference dates. The figures below therefore illustrate scale and different approaches to water management; they do not constitute a standardised ranking of drought preparedness.
| Country | Documented figure | Scope and source |
|---|---|---|
| Spain | More than 1,200 large dams; approximately 56,000 hm³ of capacity | MITECO overview. |
| France | 12,000 hm³ of capacity | 2023 French Senate report, which compares this with 54,000 hm³ in Spain. |
| Germany | 380 large dams | German Committee on Large Dams. A national storage volume is not included because a comparable figure has not been verified for this article. |
| Czech Republic | 165 reservoirs; 3,360 hm³ of total volume | Ministry of Agriculture publication, May 2020. A historical reference, not a 2026 inventory. |
| Austria | 194 large dams; 1,600 hm³ of usable volume | Ministerial publication Zahlen und Fakten 2024. Usable volume, rather than total capacity. |
Reading the units: 1 hm³ equals one million cubic metres. Total capacity and usable storage volume are different measures and should not be compared as though they were identical.
Germany: Fewer Large Dams, but Other Sources of Supply
The German Committee on Large Dams identifies 380 large dams and highlights differences in definitions between inventories. This is clearly below the Spanish figure, although counting structures alone does not establish their combined volume or the security of water supply.
Groundwater also plays an important role in Germany. The German Environment Agency states that approximately 3.6 billion cubic metres of groundwater are abstracted annually for drinking water production. Reservoirs are part of Germany’s system, rather than the entirety of its reserves and supply sources.
The Czech Republic: a Much Smaller Total Reservoir Volume
In 2020, the Czech Ministry of Agriculture reported 165 reservoirs with a total volume of 3,360 hm³, including 47 drinking water reservoirs. This is considerably below Spain’s figure, although it relates to a smaller country in both area and population, and to an earlier reference date. It should not be presented as an updated measurement for 2026.
The ministry also emphasises the country’s dependence on precipitation: most of its water flows towards neighbouring countries. Retaining some of those inflows and improving connections between supply systems are therefore important considerations when preparing for dry periods.
Austria: Hydropower Storage Does Not Tell the Whole Story
The ministerial publication Zahlen und Fakten 2024 records 194 large dams and a combined usable volume of 1.6 km³, equivalent to 1,600 hm³. Most of this water is used for electricity generation. Because this is usable volume, it would be inappropriate to divide Spain’s total capacity by this figure and present the result as a like-for-like comparison.
Austria obtains almost 100% of its drinking water from groundwater and springs, according to its responsible ministry. This changes the interpretation: less artificial storage does not necessarily mean less secure supply. Underground reserves and their replenishment are also essential.
What the Comparison Actually Shows
Spain stands out for the scale of its surface water storage infrastructure. That capacity provides scope to manage water between seasons, but is insufficient to establish that the country is better prepared overall than all of these countries. A full assessment must relate usable reserves to population, demand, natural inflows, water uses and geographical distribution. The strongest conclusion concerns a specific infrastructure advantage, rather than general superiority in drought resilience.
Why Storing Water Helps during a Dry Season
Storage helps bridge the gap between when water arrives and when it is needed. If a system receives sufficient inflows during wetter months, its reserves can support part of the demand during a subsequent period with little rainfall.
Consider two areas facing several months without rain. If one enters that period with usable reserves and adequate connections to the places where water is consumed, it has an additional margin for maintaining supply. That margin also depends on consumption: reservoir capacity alone does not determine how long the water will last.
Having Reserves Does Not Mean There Is No Drought
MITECO distinguishes between prolonged drought and temporary water scarcity. The former relates to a persistent lack of precipitation and inflows; the latter concerns difficulties in meeting demand. This distinction explains why an area can experience a dry period while retaining reserves for water supply.
Reservoirs do not make it rain or automatically maintain moisture in forests and rain-fed farmland. Nor do they eliminate the effects of successive years of insufficient inflows. The European Environment Agency continues to identify Spain among the countries affected by seasonal water scarcity, particularly in spring and summer.
Local Conditions Matter More than National Averages
National figures describe the scale of infrastructure, but do not guarantee availability in every municipality. Understanding conditions in a particular area requires examining the reserves and demands of its supply system. Spain’s official monitoring distinguishes drought and scarcity conditions across different geographical areas.
Likewise, a comparison between countries cannot by itself explain what happened in a particular year. Assessing a drought episode requires consideration of previous rainfall, temperatures, initial reserves and changing consumption, alongside existing infrastructure.
An Advantage That Requires Efficient Management
Storage capacity is an asset, but water security also requires infrastructure maintenance and demand management. MITECO highlights the importance of maintaining and rehabilitating existing dams. At European level, the European Environment Agency calls for improved water resilience and protection of aquatic ecosystems.
Spain has developed substantial water storage capacity because it has historically needed to cope with irregular water availability. This infrastructure provides an advantage over countries such as France in cushioning certain dry periods. Its effectiveness depends on sufficient inflows, reserves being available where they are needed, and water use remaining compatible with conservation of the resource.