A sharper gravity map found water storage rising beside Turkmenistan’s canal network

Two waterworks sit inside the same signal

From April 2002 through November 2025, the study estimated that terrestrial water storage in its Karakum Desert region increased by 1.2 plus or minus 0.5 gigatons per year. Terrestrial water storage is a bundle. It includes surface water, soil moisture, snow and ice, and groundwater rather than one reservoir or aquifer.

The paper says the gain was concentrated along the 720-kilometer Great Turkmen Collector, which carries irrigation runoff toward the Karashor Depression. That collector is not the Karakum Canal. Much of its water arrives through the separate canal system, which diverts water from the Amu Darya to farms farther west.

NASA’s account says the Karakum Canal and its branches are largely unlined, allowing some diverted water to infiltrate before reaching farmland. The study supports an association between the regional gain and the connected waterworks. It does not prove that canal seepage caused every change across the region.

The sharper map gives up the calendar

GRACE and GRACE-FO fly as pairs. A small change in mass below alters the pull of gravity and changes the distance between the leading and trailing spacecraft. Precise ranging instruments record those shifts, and researchers infer where mass moved.

Conventional products turn the measurements into monthly maps. Those maps preserve change through time, but their gravity signals are smoothed over large areas. The new analysis instead stacked Level-1B intersatellite ranging observations from the full record into one regression.

The result had five to 10 times the spatial resolution by area of traditional monthly mascon regression. That gain was spatial, not temporal. The method estimates one long-term trend and cannot recover how a region rose, fell or reversed from month to month.

Forty selected regions, not one global rule

The researchers compared significant storage hotspots with irrigation, land use, reservoirs and climate variables, then paired the statistical results with earlier regional research. They identified 40 regions where strong trends were spatially associated with human land or water use.

Across those selected regions, cumulative losses totaled 3,122 gigatons during the study period. Gains totaled 2,432 gigatons. These are not a complete global water budget. They are totals for the 40 regions the authors selected through their attribution process.

Traditional monthly mascon regressions underestimated the magnitudes of the regional trends by 33 percent on average. The comparison does not mean every location changed by 33 percent, and it does not mean the planet held 33 percent more or less water than scientists thought.

In North America, the Middle East and North Africa, northern Asia, and South America, one human-use variable had a standardized model coefficient with greater magnitude than any climate variable. That means it had the strongest relative relationship inside the continental model. It does not remove climate from the story or prove that one activity produced the full trend.

The picture and the measurement keep different evidence

Gravity records a combined change in mass. By itself, it cannot label the change as groundwater, a lake, snow, soil moisture or seepage. Maps, climate records, land-use data and earlier regional studies supply the context used to interpret the signal.

The 2021 astronaut photograph has the opposite strength. It shows irrigated fields and part of the Karakum Canal at one moment, but it cannot reveal the wider region’s long-term water-storage trend.

In the photograph, the canal is visible and the regional mass change is not. In the gravity map, the long-term change comes into focus and its monthly history disappears.