Outflows also declined by 21%, and total dam storage has decreased by 26%, now standing at 23.67 billion cubic meters.
National rainfall has dropped 39% below the long-term 57-year average and 40% compared to last year.
The hardest-hit provinces include Hormozgan (-78%), Sistan and Baluchestan (-76%), and Bushehr (-54%). Tehran’s major dams — including Amirkabir, Lar, Taleqan, and Latian — have also seen significant declines in water levels.
Experts attribute these alarming figures to climate change, rising temperatures, and increased evaporation, urging immediate water consumption management across households, agriculture, and industry.
Only Gilan province saw a slight rainfall increase (+7%), while all others recorded deficits.