OPTIMIZING RIVER DIVERSION UNDER HYDRAULIC AND HYDROLOGIC UNCERTAINTIES

Flood diversion during dam construction has a major influence on the c onstruction period, and its cost represents a significant part of the total project cost. In general, selection of diversion system capacity and the dimension of the system component are socioeconomic and techn ical decisions. Quantifying uncertainties is an important problem in r isk-based design of hydraulic structures. This paper presents an optim ization model of river diversion that incorporates the uncertainty of the flood magnitude estimator and the hydraulic uncertainties. Confide nce interval for the design flood considers the uncertainty associated with an estimated skew coefficient. For hydraulic uncertainties a fir st-order second-moment analysis is carried out. The diversion design f lood and the dimensions of the system components are explicitly treate d as decision variables. To study its usefulness, the model is applied to the Karoon Dam site, which is now-under the design phase in southe rn Iran. Results show that the model is a promising tool that could be used efficiently as a design aid.