Hydrological Characteristics of the Gharraf Rivers

Given that the study area is located within the dry regions of the country, the total reliance on surface water represented by the Gharraf River is primarily, in addition to the loss of rain to cover losses due to evaporation and the absence of seasonal rivers or tributaries that supply the river with water, so the area was ruled by a permanent water deficit, and for this reason water management in the Gharraf Basin must receive sufficient attention to secure water protests and other various requirements. The Gharraf River is one of the rivers that branch off from the Tigris River from the front of the Kut Dam and heads towards the southeastern administrative borders of Wasit Governorate, then enters Nasiriyah Governorate at dawn with a length of (230) km, of which (86) km are in Wasit Governorate. The hydrological study showed that the natural conditions affecting the Gharraf River, such as high temperatures, increased evaporation, filtration and sediment values, caused its water discharges to decrease during the period (1985-2020) from 192 m3/s to 146 m3/s. The river was also calibrated with field levels using the (HEC-RAS) program, so the average Manninck coefficient was (0.026), in addition to knowing the effect of return water (RATING CURVES). There was a significant effect when closing and opening the gates of the neighborhood regulator. It was noted that the levels affected by the gate openings were more than 175 m3/s. Most of the streams branching off from the Gharraf River, which are located on the left side of the river, needed a discharge of (137) m3/s, and the right bank of the river needed (113) m3/s along its length