DETERMINATION OF HYDRODYNAMIC RESISTANCE COEFFICIENT (MANNING’S COEFFICIENT) IN SHATT AL ARAB RIVER, SOUTHERN OF IRAQ-BASRAH

Abstract

Shatt al-Arab River is considered one of the systems affected by the phenomenon of tides and has the economic, environmental and historical significance of the city of Basra in southern of Iraq. Manning or roughness coefficient (n) is considered an important bases in the hydraulic studies of river's flow. Experimental methods are used to calculate the value of (n) depending on the field's measurements for six measuring stations (Fao, Seehan, Aboflos, Al-Ashar, Ektiban, and Al-Sharash). It is concluded that n-value is varying along the Shatt al-Arab river, ranging between (0.0115- 0.06) along the river course. The highest value is recorded in Al-Sharash station (0.06) where many factors are interfere, including the velocity of currents, the nature and size of the sediment surface and shape of the river bottom (level, or zigzag).