Istanbul Dams Drop to 49.54% Capacity Amid Summer Heat and High Consumption

Istanbul's water reserves are showing a concerning decline, with the average dam occupancy rate falling to 49.54% as of August 15, 2026. This marks a significant drop from the 58.68% recorded in mid-July, according to the latest figures released by the Istanbul Water and Sewerage Administration (İSKİ).

The rapid decrease in water levels during August is primarily attributed to the intense summer heat, which accelerates evaporation, coupled with a surge in water consumption by the city's residents. This trend highlights the vulnerability of the city's water supply to seasonal weather patterns and increasing demand.

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The general average occupancy rate of the dams supplying Istanbul's water needs has fallen to 49.54%.

While dams on the Anatolian side, such as Ömerli and Elmalı, continue to supply a substantial portion of Istanbul's water needs, dams located on the European side are facing critical shortages. Specifically, the Istrancalar, Pabuçdere, and Sazlıdere dams have fallen below crucial occupancy thresholds, raising concerns about the overall water security for the western part of the metropolis.

İSKİ provided a detailed breakdown of the dam occupancy rates on August 15, 2026: Ömerli Dam stood at 71.05%, Darlık Dam at 67.7%, Elmalı Dam at 80.7%, Terkos Dam at 42.12%, Alibey Dam at 48.33%, Büyükçekmece Dam at 35.5%, Sazlıdere Dam at 28.37%, Istrancalar Dam at 34.01%, Kazandere Dam at 23.4%, and Pabuçdere Dam at 17.35%. The low levels in several of these dams underscore the urgent need for water conservation measures.

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The rapid decline in the general average from 58.68% in mid-July to August clearly shows the high evaporation caused by summer heat and increased water consumption.