Determining Runoff Coefficient For Kalecik Basin in Using Fuzzy Smrgt Method

Precipitation causes runoff with significant uncertainty. The rainfall-runoff modeling relationship depends on the runoff coefficient. Many models have been developed with different methods to calculate the runoff coefficient. Black box or fuzzy models can be preferred instead of deterministic methods in uncertain natural events. However, black box methods often do not consider the event's physical aspect. Therefore, in the present study, Simple Membership Functions and Fuzzy Rules Generation Technique (SMRGT) which base on fuzzy logic was preferred in determining the runoff coefficient since it also reflects the physical cause-effect relationship of the event. By this way, both the hydrological event's uncertainty and physical aspects were addressed. Therefore, it can be used for any basin when the limit values of the variables are expanded. Correctly determining fuzzy sets and fuzzy rule bases are essential points to be considered in fuzzy modeling. According to the literature, SMRGT is the best one to use for this purpose. On the other hand, SMRGT is relatively new. Meteorological, geomorphological, and land use-related characteristics were considered for modeling. The Kalecik Basin's runoff coefficient is found as 0.28 which is lesser than the average of Turkey. The model has 2.28% of MARE.