Page - 918 - in Book of Full Papers - Symposium Hydro Engineering

COMMISSION INTERNATIONALE DES GRANDS BARRAGES ------- VINGT-SIXIÈME CONGRÈS DES GRANDS BARRAGES Autriche, juillet 2018 ------- SAFETY ASSESSMENT FOR LARGE RESERVOIR CONSTRUCTED FOR DOMESTIC WATER NEAR URBAN AREAS AND A CASE STUDY Hasan TOSUN Professor, Engineering Faculty, ESKİSEHİR OSMANGAZI UNIVERSITY TURKEY 1. INTRODUCTION Increasing demand for water results to construct large reservoirs in or near urban areas. Same situation can be resulted by extending settlement area around reservoirs, which were constructed many years ago. Therefore, dams with large reservoirs, which are located in or near urban areas, have a high-risk potential for downstream life and property. In other words, a problem on public safety can raise up for people and live life on downstream for urban areas. Safety assessment is a most significant concept for large reservoir, especially constructed in or near urban area. It is clear that there are mainly two important factors acting on total risk for dam structures. These are (1) the seismic hazard rating of dam site and (2) the risk rating of the dam and appurtenant structures. The seismic hazard of a dam site can be based on the peak ground acceleration. This value derived from the defined design earthquake produces the main seismic loads. For a preliminary study, the existing map of seismic zones can be used to estimate the seismic hazard of a dam site. The risk rating of the dam should be based on the capacity of the reservoir, the height of the dam, the evacuation requirements, and the potential downstream damages. In general, the seismic and risk ratings are evaluated separately for ICOLD method. However, BUREAU method combined these two factors to define the total risk factor for dam structure. In the study six dams, namely Alacatlı Kutlu Aktas, Balcova, Gordes, Guzelhisar, Tahtalı and Urkmez dams in Kucuk Menderes and Gediz basins, were considered. These dams are maibly utilized for providing domestic water of Izmir Metropolitan Area. In 2017, The water demand was totally 225 millon cubic meter for this area. The 42.3 percent of this demand was provided by surface water, which are impounded in the reservoirs of dams mentioned above while others provided by groundwater resources. This paper deals with an evaluation of seismic 918