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7 junio 2024

What Is the Purpose of Reservoirs? Main Uses and Benefits

Reservoirs are essential for irrigation, energy production, and environmental management. Discover their importance and how they are managed in Spain.

Operaria de Endesa en una central hidroeléctrica con embalse
Mequinenza Hydropower Plant (Zaragoza).

Access to water is and will continue to be one of the main challenges facing our planet in the coming years. Efficient use of water will be key to ensuring availability of this resource, as scarce as it is valuable. In water management, the use of reservoirs is particularly important.

Spain has over 375 reservoirs, which are crucial for water supply, agriculture, and hydropower generation.

Reservoirs are large, man-made water storage areas created by constructing a dam that holds back river or stream water. Unlike ponds, which can be natural or artificial, reservoirs are always artificial, have a greater water retention capacity, and their construction requires preliminary surveys.

Though they are often used as tourist attractions or to practise water sports, these bodies of water serve many more functions than you might imagine. Find out about their many functions below!

 

Uses of Reservoirs

To understand the importance of reservoirs, one needs to know their uses and the benefits they provide:

  • Supplying drinking water to the population. This is their primary use in Spain, as defined by the Water Act.
  • Agricultural irrigation. Reservoirs store water for irrigating agricultural land and ensure sufficient flow rates for agricultural uses.
  • Generating renewable energy. Many reservoirs contain hydropower plants that generate energy by capturing the energy of falling water. Additionally, they facilitate the integration of other renewable energy sources into the system by storing energy in the form of water.
  • Environmental conservation. Reservoirs help to control the amount of water in rivers by regulating their flow. This is beneficial because it helps them to maintain a constant flow, preventing both droughts and floods. They protect the local fauna and flora by ensuring a stable water flow.
  • Serving as firebreaks. In case of emergency, firefighters can use water from reservoirs to fight fires. Hydroplanes and helicopters can also refill their tanks from reservoirs.
  • They help manage flood risks by controlling peak flows.
  • They can be used for recreational activities. Reservoirs provide opportunities for fishing, boating, canoeing, and other water activities. The surrounding areas are ideal environments for hiking and cycling.

To carry out these functions effectively, careful and efficient management is crucial. Which raises the question... Who manages reservoirs in Spain?

Embalse de Eume
Eume reservoir.

 

Who Manages Reservoirs in Spain?

The responsibility for managing reservoirs in Spain is shared by the Ministry for the Ecological Transition and Demographic Challenge and the River Basin Authorities. Together, they ensure the efficient and sustainable use of water resources, guaranteeing water supply, flood protection, and environmental conservation. Find out how:

 

Ministry for the Ecological Transition and Demographic Challenge (MITECO)

The MITECO is the central authority overseeing national water policy. Through the Directorate General for Water, it develops and outlines hydrological plans, defines sustainable management policies, ensures compliance with environmental regulations, and protects aquatic ecosystems.

It also publishes regular reports on drought conditions and water scarcity, providing updated data on reservoir levels and resource availability.

 

River Basin Authorities

River Basin Authorities are autonomous entities under MITECO, in charge of managing water resources within their corresponding hydrographic basin. River basins may span several autonomous communities, in which case they are managed by MITECO, or contained within a community, in which case they fall under the responsibility of the Regional Government with competency for water management .

These entities include Hydrographic Confederations such as those of the Ebro, Tajo, or Duero rivers.

Their main functions include regulating water use for different purposes (such as agricultural irrigation), upholding the Hydraulic Public Domainmaintaining water infrastructures, supervising water quality and quantity through constant monitoring, and facilitating citizen participation through the basin's Water Council.

What about Management During Meteorological Crises? Managing water during drought periods is crucial to ensure the supply and efficient use of water resources. Here's how it's managed in Spain.

 

How is Water Managed During Drought Periods?

In drought conditions, River Basin Authorities manage water use to meet priority needs such as drinking water supply for human consumption, agricultural irrigation, and industrial uses.

How do they do it? They coordinate water release schedules and volumes to maximise efficiency and minimise waste, particularly during night-time, when irrigation demand is higher.

Hydropower production is carried out in a manner compatible with other water uses, since water is not depleted, but rather reintegrated into the watercourse so that it can be reused for new purposes. Additionally, in extreme situations, hydropower plants can adjust their production to release only the minimum amount of water necessary.

 

The Importance of Reservoirs in Spain

Reservoirs play a crucial role in regulating and storing water, especially in a country like Spain, with significant climate variability.

In Spain, reservoirs ensure water supply for human consumption, agriculture, and industry. They also help to prevent floods by controlling water release during heavy rainfall episodes.

Moreover, Spanish reservoirs contribute significantly to renewable energy generation, reducing dependence on fossil fuels. This helps make the economy more sustainable and reduces greenhouse gas emissions while protecting the environment.

Central hidroeléctrica de Cala, Guillena (Sevilla).
Cala Hydropower Plant, Guillena (Seville).

In addition, to optimise reservoir management, since 2015 the State Meteorological Agency (AEMet) and the Directorate General for Water have developed S-ClimWaRe. This tool provides seasonal predictions on rainfall and water inflows, assisting in decision-making for effective water management.

Climate change is affecting rainfall patterns, making reservoir management increasingly challenging. Therefore, adapting reservoir management to current climate challenges is essential. Innovations in water management will be crucial for optimising reservoir use in Spain.

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