RİSK PERCEPT I ON OF DR I NK I NG WATER , WATERSHED REGULAT I ON AND WATER RESOURCE MANAGEMENT

1. Istanbul, where Two Continents Meet RİSK PERCEPTION OF DRINKING WATER, WATERSHED REGULATION AND WATER RESOURCE MANAGEMENT IN ISTANBUL M.E.BIRPINAR, G.KANAT and A.DEMIR Yildiz Technical University 34349 Besiktas, Istanbul/TURKEY

2. WATER DEMAND • Population increase of the city is still higher than Turkey’s overall rate of 25 per thousand and leads to water management problems.  • The present water demand of Istanbul is approximately 1100 million m3/yr and also it is estimated to double within the next 20 years. • Explosive urbanization in the 1970s and peaking at 14% in the early 1980s forced Istanbul to once again expand and renovate its water supply system.

3. WATER DEMAND • In the 1989s, the amount supplied to the city increased to about 400 million m3/year, but this was still insufficient to meet the city’s needs. By 1999, this amount increased to about 900 million m3/year, although in dry seasons, the incoming water supply can be up to 20% less. • In 1989 and 1994, water shortage was so deep that people in some districts demanded not more than only one day in a week to receive water from their taps. • Drinking water requirement is supplied from 16 dams and lakes.

4. Main reservoirs and dams for drinking water supply in Istanbul City.

5. WATERSHED REGULATİON • Drinking water basins have a length of 250 km. and a width of 100 km. the total area of the water basins controlled by ISKI is 4.057 km2. • On 13 March 1984, first regulation to Protect Surface Water Sources from Pollution • Regulations divide the drainage basins of reservoirs into four protection zones.(0-300-1000-2000-5000 m.)

6. Suggestions For Solving The Problems of Drinking Water Basins • Regulation of 1984 had revised occasionally, 14 times until 2002 • Two main principles of the last regulation. - To take care of protection-usage balance.- To accept the existing conditions as a reality. • Control of the illegal housing settlements in a wide basin exceeds the authority of ISKI. New arrangements for sufficient inspection and control are needed.

7. Water Resource Management After Drought Years • In the summer of 1985 and 1990, there was long watering limits in the network more than a week because of severe droughts combining with slack management of water authorities. • Following years, there has been many efforts to balance water shortage. Today, it is almost balanced.

8. Water volumes supplied to Istanbul during drought years

9. Risk Perception of Drinking Water and Bottled Water Use • In cities of Turkey, especially in hot summer season, people used to drink tap water in the last decades. However, the situation has been changed due to low network water quality and increased pollution concern, especially in big cities. • In Turkey, bottled water consumption increased up to 4 million m3/year in the last years and financial value was about 170 million $ despite a strong economical crisis in that year. Metropolitan cities in the country, which have poor water network quality because of rapid immigration and urbanization, take the big share of bottled water consumption. • In order to state public's perception of drinking water and bottled water consumption in Istanbul, a survey of including 300 people from different districts of the city has been done.

11. Risk Perception of Drinking Water and Bottled Water Use • Many of the people never drink tap water and some people do not use it for even cooking and hot drinking (tea, coffee, etc.). Only 4% of the surveyed group answered to drink tap water without any hesitation. • When buying bottled water many people prefer to choose the renowned brands of big companies. • Risk perception about drinking water is affected by the level of awareness of drinking water problem, presence of a drinking water contamination problem, and the chronicity of a problem. • The future presents many challenges in dealing with the public and maintaining public confidence. Administration and treatment changes for drinking water will be required to meet new demands and regulations in the future.

12. RESULTS • Adequate application of restrictions in protection zones are very important for solving the problems of drinking water basins. • Control of the illegal housing settlements in a wide basin exceeds the authority of ISKI. New arrangements for sufficient inspection and control are needed. • Water sources of Istanbul City are still in danger due to intensive migration to the city, as well as inner city moving to Northern forest and unpopulated areas, especially after the strong earthquake.

13. RESULTS • When there is a water famine in any country, the first step taken to cope with it is usually to give priority to the study of methods for the development of water resources, such as increasing the possible water intake, construction of dams, reducing the amount of agricultural or industrial use, etc. In fact, when water shortages are likely to occur in large cities, it will be fundamental solution to the problem to take steps on a national land planning scale such as the restriction of immigration to the cities, the relocation of industry and other-similar means. • The future presents many challenges in dealing with the public and maintaining public confidence. Administration and treatment changes for drinking water will be required to meet new demands and regulations in the future.