İSKİ - Water Resources

İstanbul is supplied with only surface water resources. Water from rainfall times are collected in dams and regulators, and then supplied to the city upon necessary treatment processes. To meet the increasing water demand in İstanbul due to population increase and geographical expansion of service areas, potable water is provided from a long range of water basins extending from Tekirdağ on the European side to Düzce on the Asian side.

Water Resources in Istanbul

Water Resource	Annual Yield (Million m³)	Max. Collection Volume (Million m³)	Opening Year
Ömerli Dam	220	235.371	1972
Darlık Dam	97	107.500	1989
Elmalı 1 and 2 Dams	15	9.600	1893-1950
Terkos Dam	142	162.241	1883
Alibeyköy Dam	36	34.143	1972
Büyükçekmece Dam	100	148.943	1989
Sazlıdere Dam	55	88.730	1998
Istrancalar (Düzdere, Kuzuludere, Büyükdere, Sultanbahçedere, Elmalıdere)	75	6.231	1995-1997
Kazandere Dam	100	17.424	1997
Pabuçdere Dam	60	58.500	2000
Yeşilçay Regulator	145	-	2004
Melen 1 and 2 Regulators	575	-	2007-2014
Yeşilvadi Regulator	10	-	1992
Şile Caisson Wells	30	-	1996
Total	1 Billion 660 Million m³/ Year	868.683