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News article8 April 2019

How do lakes and reservoirs behave across decades?

The Merowe Reservoir on the river Nile(Sudan)
The Merowe Reservoir on the river Nile (Sudan)
© EU,2019

The JRC developed a new powerful method to monitor the reservoir volume dynamics at the global scale. It paves the way for future hydrological studies and satellite missions.

Water reservoirs and lakes cover less than 3% of the Earth's land surface. However, the benefits they deliver to people and nature are enormous: they serve nearly half of the irrigation-based agricultural sector globally and provide resources for hydropower, domestic and industrial water use, just to mention a few.

The Joint Research Centre has been at the forefront of their monitoring for years: thanks to the Global Water Surface Explorer, JRC scientists map the dynamic behaviour of lakes and reservoirs and derive hydrological models to simulate the volume and capacity of future basins.

They have recently developed a new methodology to monitor the reservoir volume dynamics at the global scale: thanks to the combined use of satellite altimetry data and of the 30m resolution data of the Global Water Surface Explorer, it is now possible to measure lake volume dynamics, which is fundamental to improving their representation in large-scale hydrological models.

“Climate change and rising global energy and food demands are increasingly putting pressure on water reservoirs. And when their storage capacity decreases persistently, essential services such as hydropower energy production and/or irrigation water availability are at risk” says Ad de Roo, one of the researchers involved.

"By combining lake areas and water levels, we derived the hypsometry relationship for 137 lakes over all continents" he continues. "In other words, we developed a method to quantify the amount of water in lakes and reservoirs based on the extent of the water surface".

Their work contributes to one of the target indicators set by the Sustainable Development Goals and paves the way for future hydrology studies and satellite missions.

(The above satellite image shows the Merowe Reservoir, which is one of the largest contemporary hydropower facility in Africa. It is situated on the river Nile, in northern Sudan and was filled in 2008. The dark blue - within the new reservoir - documents the historical location of the Nile River (prior to the reservoir filling) and the green areas correspond to the extent of the reservoir. The dark green areas document permanently flooded areas, while the light green maps the seasonally flooded areas associated with the seasonal reservoir volume dynamics.)

Further information

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Publication date
8 April 2019