It is generally believed that a range of flows or a flow regime is responsible for channel formation and maintenance rather than a single flow rate. Conversely, depiction of the channel-forming discharge as a single flow rate that represents the collective effects of a range of discharges is a convenient method for designing management schemes for controlled rivers. Three approaches are available for the quantification of channel forming discharge (Qcf): effective discharge (Qeff), bank-full discharge (Qbf) and return interval discharge (Qri). In the present study the variability in the relative magnitudes of the three approaches of estimating Qcf has been studied using literature review and by analyzing two reaches of Jhelum River near Hattian Bala Gauging Station and Azad Patan Gauging Station. The three approaches provide comparative values for non-incised river reaches having low flow variability and are having coarse beds. It has been observed that for the flashy hydrology, values of Qeff, are usually higher than Qbf and for the incised river reaches values of Qbf are much higher than the Qeff. The results of the study are in comparison with the results of previous studies regarding flashy hydrology and sand beds. The flow duration of the effective discharge for studied reaches is 13% to 4.6% of time or 48 days per year to 13 days per year. These results support the conclusion of Wolman and Miller (1960) that the effective discharge is a comparatively frequent flow that happens on an average of a number of days per year. This study can be utilized by local designers especially for designing hydraulic structures on Jhelum River.
Muhammad Mubashir Qureshi, Abdul Sattar Shakir, Eric Lesleighter. (2013) Channel Forming Discharge in Rivers: A Case Study of Jhelum River in Pakistan, Pakistan Journal of Engineering and Applied Sciences, Volume 12, Issue 1.