An Assessment of Impact of Cloud Seeding on Local Rainfall- A Case Study of First Part of the Iski Rain Enhancement Program Conducted in Istanbul, Turkey during 1990-1991

Abstract

Abstract:Major metropolitan areas of Turkey suffered from extensive drought and associated water shortage during the late 1980s and early 1990s. Water levels at major dam lakes dropped below their critical levels in Marmara, and Central and Western Anatolian regions. The impact of resulting water shortages was greatest especially on the drinking water supplies during summer months when the temperatures peaked. A number of rainfall enhancement projects in response to the emerging water shortage problems developed and were put into implementation by the local authorities of Istanbul, Ankara, and Ä°zmir. Nevertheless economic viability of the projects was not considered seriously. The efforts were directed to find immediate solution to supply water to local communities who suffered from the shortage of water in the urban areas. Istanbul Municipality and Istanbul Water and Drainage Works (ISKI) launched “ISKI Rain Enhancement” project, to meet immediate water demand of the city of Istanbul. It was the first operational rainfall enhancement program in the country and included cloud seeding in a nearly 2100 km 2 area covering four main water catchments which supply drinking water to the Istanbul Metropolitan area. The first rainfall enhancement phase covered October 1990 through March 1992, and later extended to 1993 and 1994. This study presents an analysis of the first phase of the ISKI rainfall enhancement program, which covered October 1990 through May 1991 period. The study focuses on rainfall data of target and control areas in and near the vicinity of the water basins where the cloud seeding was conducted in order to assess effectiveness of the seeding.