Introduction
In recent years, numerous studies have been conducted to evaluate discharge. A practical approach in this regard is to evaluate the discharge at different water levels using the available information on a reference water level. Using the stage-discharge curve, the discharge rate at other levels can be predicted and evaluated if the discharge is known at one surface level. Maghrebi et al. presented a method to determine the stage-discharge relationship.This relationship compares the discharge at two different levels of a cross-section. Therefore, using the discharge collected at level i as reference point, the discharge values at other levels can be evaluated. Therefore, the current study investigated the effect of changing these powers on the discharge evaluation error.

Methodology
A reasonable value for the powers must first be considered to investigate the effect of changing the stage-discharge relationship’s powers on the amount of discharge evaluation error. Then, in different examples, coding should be done so that the powers are changed and for each power, the discharge evaluation error is calculated and reported separately. Then, it is checked whether the error has been reduced or not. The error relations and the Maghrebi relation are coded in MATLAB software for the cross-section of Figure 2. The discharge Flow evaluation error values for FCF-Series 10 were calculated separately for the levels specified in Figure 3 by considering the interval [-2,2] for each power of the Maghrebi relationship and its changes are shown in Figures 5 to 10. In these figures, the horizontal dashed line shows the error value in Maghrebi relation to evaluate discharge.



Results and Discussion
In Figures 5 to 10, the reduction of the discharge evaluation error can be seen in some ranges of the power change interval. The maximum error reduction can be seen in Figure 10, Case C, which shows a reduction of about 4%. The error reduction ranges are given in Table 3.
Figures 5 to 10 and the results presented in Table 3 show that it is possible to improve the performance of the Maghrebi relation by changing the relationship powers within the suggested range. On the other hand, it was stated earlier that up to a 4% reduction in discharge evaluation error can be achieved.
Conclusion
Finally, this study provides a suggested range for each power. The most important result of the present article is that changing the powers of the stage-discharge relation can reduce the discharge evaluation error. The results show that changing the powers reduce the discharge evaluation error by more than 5%.