TY - JOUR ID - TI - استنباط معادلة لتقدير التصريف الحقيقي للقنوات حصوية القعر والحاملة للرسابات AU - أنس محمود محمد رشيد AU - عبد الصابر إبراهيم بكر PY - 2005 VL - 5 IS - 1 SP - 19 EP - 31 JO - Basrah Journal for Engineering Sciences مجلة البصرة للعلوم الهندسية SN - 18146120 23118385 AB - A Laboratory flume (l0m * 0.3m * 0.45m) was used to study the effect of sediment inflow on the roughness of three different sizes of bed materials. Their sizes were ranging between (O.02-O.03m), (0.03-O.04m), and (0.04-0.05m) in diameter. Three different sizes of sand (0.36mm, 0.4mm, and 0.67mm) were used to conduct the experiments. The corresponding standard deviations were 0.243, 0.267, and 0.32 respectively. Four different discharges (0.012, 0.0141, 0.0161, 0.0 18 m3/s) and slopes (0.0075, 0.01, 0.0125, 0.0 15) were used to study the effect of the slope. Results indicated that for a given discharge, the resistance to flow decreases when the channel was subjected to the inflow of sediment.• The sediment gradually fills up the pores between the gravel, causing a gradual decrease of the bed roughness coefficient to extent that the sediment fills all pores. The relative of Manning coefficient (n/ng) 0.64 was greatest due to the change of the bed materials from gravel to sand. To be able to use the established stage discharge relation, a correction factor is needed when such channels are subjected to appreciable amount of sediment inflow. Empirical equation was developed in this research. This equation showed a good agreement with the measured values of the Manning $ coefficient. The maximum percent error of this equation is ± 7.3%.

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