We drew the ten dams side by side, each in proportion to its size.
Each dam’s percentage is against its own capacity. So a small lake at 90% can hold less water than a big one at 60%. The figures are from the 6 November 2026 reading; all 10 dams are below.
Fullest: Istrancalar 98.0%. Emptiest: Pabuçdere 7.7%.
Each chamber is as wide as the dam’s share of the city’s total capacity, and its water stands as high as the dam is full. The dashed line is full. As the page opens, the water moves from where it stood a week ago to today.
How much water, and how it has changed
| Dam | Fill level | Water, million m³ | 7 days | 30 days | 30-day trend | Capacity, million m³ | Share of the city |
|---|---|---|---|---|---|---|---|
| TerkosNormal | 50.5% | 98.9 | +12.8 | +19.2 | 196.0 | 22.6% | |
| BüyükçekmeceModerate | 39.8% | 51.7 | +8.5 | +13.8 | 129.9 | 15.0% | |
| SazlıdereNormal | 40.8% | 36.2 | +7.7 | +20.4 | 88.7 | 10.2% | |
| PabuçdereCritical | 7.7% | 2.7 | +5.0 | +5.2 | 35.2 | 4.1% | |
| AlibeySafe | 79.7% | 27.2 | +8.0 | +44.6 | 34.1 | 3.9% | |
| KazandereCritical | 11.6% | 2.4 | +8.3 | +2.2 | 21.1 | 2.4% | |
| IstrancalarSafe | 98.0% | 6.1 | +55.9 | +80.4 | 6.2 | 0.7% |
| Dam | Fill level | Water, million m³ | 7 days | 30 days | 30-day trend | Capacity, million m³ | Share of the city |
|---|---|---|---|---|---|---|---|
| ÖmerliSafe | 83.1% | 203.2 | +3.9 | +26.9 | 244.5 | 28.2% | |
| DarlıkSafe | 95.2% | 97.6 | +3.2 | +34.4 | 102.5 | 11.8% | |
| ElmalıSafe | 80.8% | 7.8 | +19.7 | −3.2 | 9.6 | 1.1% |
Fill levels and changes are against each dam’s own capacity; changes are in percentage points. The trend lines share one scale, so a change at one dam can be compared with the others. The rises over the last week come from the rain of 27–29 October, when about 38 mm fell on the dam catchments.
- Critical0%–20%
- Moderate20%–40%
- Normal40%–60%
- Safe60%–100%
Status labels follow a fixed rule on the fill level alone: below 20% “Critical”, 20–40% “Moderate”, 40–60% “Normal”, 60% and above “Safe”. They are not an official assessment. On their own they say neither that cuts are coming nor that there is enough water.
Forecast by side
European side
We don’t show a separate forecast for this side. After the last big storm the city model forecast too high, and that is not fixed yet. This side is worked out with the same model.
Asian side
We don’t show a separate forecast for this side. In the hindcast its 30-day range covered 73% of outcomes, where it should be close to 80%.
Each side’s forecast comes from the same model as the city’s, worked out with that side’s own dams, catchments and capacity. A side is shown only if, in its own hindcast, it beat every simple rule and its range covered close to 80% of outcomes. The range holds with 80% probability.
Where the capacities come from
We don’t take volumes from other sites. We work them out ourselves, by multiplying each dam’s fill percentage by its capacity. Since 20 February 2024 we use the capacity table published by dolulukorani.com (total 867.8 million m³), which matches İSKİ’s 2026 city percentages best. The site told us it corrected the table on 15 October 2026. For earlier dates, İSKİ’s January 2024 list applies (total 868.7 million m³).
The two lists differ by more than 10% for Terkos, Büyükçekmece, Pabuçdere, Kazandere. So per-dam volumes and capacity shares before 20 February 2024 can’t be compared with later ones. The city total is not affected: the two totals differ by only 0.1%.
İSKİ has not confirmed these lists yet. Per-dam percentages come from İSKİ, our primary source. On days when İSKİ’s figures are not available we use dolulukorani.com as a second source.
| Dam | Current table | İSKİ, January 2024 | Difference (million m³) |
|---|---|---|---|
| Terkos | 196.0 | 162.2 | +33.8 |
| Büyükçekmece | 129.9 | 148.9 | −19.0 |
| Sazlıdere | 88.7 | 88.7 | 0.0 |
| Pabuçdere | 35.2 | 58.5 | −23.3 |
| Alibey | 34.1 | 34.1 | 0.0 |
| Kazandere | 21.1 | 17.4 | +3.7 |
| Istrancalar | 6.2 | 6.2 | 0.0 |
| Ömerli | 244.5 | 235.4 | +9.2 |
| Darlık | 102.5 | 107.5 | −5.0 |
| Elmalı | 9.6 | 9.6 | 0.0 |