Flood Dynamics in the Marshes – Natural Conditions

Zaid Hakim Jiyad
Under the supervision of Lect. Dr. Ali Khazal Jawad

The area of areas flooded with water is subject to change during the year, according to the hydrological system. Drought years lead to the recession of the flooded lands, while years rich in rainfall contribute to the increase of the area of the marshes.
The natural system of inflows and outflows of the marshes depends largely on the presence of flood peaks and, in general, on the hydrological system of the rivers that bring water to the marshes. Before human intervention in the hydraulic system, the upstream area of the marshes was periodically flooded during floods. Conversely, during drought periods, the area of the flooded areas decreased, causing a succession in the behavior of wetlands, which generally helped in the development of biodiversity and the improvement of environmental conditions to the maximum extent: the variation of flood extension and water depth creates favorable conditions for plants and animals. Moreover, there are no dams and barriers made by man under natural conditions. Consequently, there was less real constraint on the extent of inundation, except for natural levees and gradual changes in terrain elevation. The peaks of large flows entering these wetlands and flooding were naturally mitigated as the water spread across the floodplains. The large volumes of water moving through the wetlands helped maintain a high level of connectivity between the marshes and the various rivers.