Terrestrial water storage loss for 7 basins on Tibetan Plateau overestimated by 10%: Study

Sub: Geo

Sec: Hydrology

Overestimation of Terrestrial Water Storage Loss on the Tibetan Plateau

Recent research has revealed significant overestimation of terrestrial water storage (TWS) loss in the Tibetan Plateau’s major headwater basins, with errors reaching up to 50.8% in the Indus River basin and 77.6% in the Yarkant River basin.

Key Findings

Terrestrial water storage (TWS) includes water in ice caps, glaciers, snow cover, soil moisture, groundwater, surface water bodies, and biomass.
The study shows that neglecting sediment transport in these estimates leads to an average overestimation of TWS loss by 10.1% across the Tibetan Plateau’s seven headwater basins.
This overestimation equates to the annual water needs of an additional 0.62 million people in surrounding areas.
Long-term observations from 2002-2017 indicate that sediment transport contributes 0.35 gigatonnes per year (Gt yr−1) to the total terrestrial mass storage (TMS) decrease of 3.85 Gt yr−1.

Basins and Erosion:

Studied Basins: The research focused on the Yarlung Tsangpo, Nujiang, Yangtze, Indus, Yellow, Lancang, and Yarkant rivers.
Erosion Rates: Soil erosion is particularly high in the western, northern, and southern regions of the Tibetan Plateau, with rates up to 39.1 Mg ha−1 yr−1 in the Indus basin and 34.7 Mg ha−1 yr−1 in the Yarkant basin.
Southeast TP Basins: Moderate erosion rates in southeast TP basins ranged from 0.007 Gt yr−1 to 0.177 Gt yr−1.

Implications

Regional Hydrological Cycle: The Tibetan Plateau, known as the ‘water tower of Asia,’ is crucial for the headwaters of more than 10 large Asian rivers. Changes in TWS can affect water availability for nearly 2 billion people downstream.
Climate Adaptation: Improved accuracy in TWS estimation aids in climate adaptation and sustainable water resource management.
Future Risks: Increased runoff and sediment fluxes from high mountain Asia could double by 2050 under extreme climate change scenarios, impacting hydropower, food security, and the environment.

Source: DTE