A new study has provided the clearest picture yet of how much water is stored in China's lakes, finding that the country's natural lakes contain about 1,174 km³ of water, including around 335 km³ of freshwater, while eastern population centers have direct access to only a limited share of these natural freshwater resources.

The study, published in the journal National Science Review, was conducted by a research team led by researchers from the Nanjing Institute of Geography and Limnology under the Chinese Academy of Sciences (NIGLAS).

Using nationwide lake survey data collected over the past three decades and advanced spatial statistical methods, the researchers carried out the first systematic nationwide assessment of lake depth and freshwater–saline lake types across China, quantifying water storage in 2,713 natural lakes larger than 1 km².

To strengthen the reliability of the assessment, the team integrated data from nationwide lake surveys, scientific expeditions and water resource investigations. The researchers compiled high-precision depth and bathymetric measurements from hundreds of lakes across the country and combined them with spatial statistical modeling.

The findings reveal a striking geographical imbalance in freshwater distribution. Nearly 65% of China's natural freshwater lake storage is concentrated in a small number of deep lakes in western inland basins, particularly on the Tibetan Plateau. This challenges the traditional perception that freshwater lakes are mainly concentrated in eastern China.

By contrast, lakes in eastern plains are generally shallower and store far less water. About 81% of China's population lives in eastern regions, yet these areas have direct access to only around 23% of the country's natural freshwater lake storage. Water quality degradation in some eastern lakes further reduces the amount of safely usable freshwater.

The study also noted that China's extensive reservoir network plays an important role in supporting water availability and easing regional disparities in natural freshwater resources.

“This study provides the most comprehensive assessment to date of China's natural lake freshwater resources,” said Song Chunqiao, a researcher at NIGLAS and first author of the study.

“By combining large-scale field investigations with advanced statistical methods, we were able to move beyond traditional surface observations and better understand how much water China's lakes actually store and where freshwater resources are concentrated,” Song said. “The findings provide an important scientific basis for water resource management and long-term water security planning.”