Delineation Suitable Rainwater Harvesting Sites in Wadi Al-Mohammadi, Iraq

Abstract

Water harvesting has become one of the topics of concern to most water specialists, due to its importance in managing water and preserving it from squandering. Wadi Al-Mohammadi is an example of a valley that needs the application of water harvesting and the exploitation of rainwater at all levels, being one of the main valleys in the Iraqi desert where surface water is lacking. The outcomes for water harvesting were derived using the SWAT model. Morphometric, the basin’s shape is far from being circular. Climatologic, the trend line indicates a clear increase in the total rainfall, relative humidity, temperature, and solar radiation, while the trend line indicates a decrease in the wind speed during the observed period. The main contributor to the total flow of Wadi Al-Mohammadi basin was surface runoff of about 99%, the base flow of about 1%, while the groundwater flow did not contribute any amount of that water. The annual average flow discharge was 0.138 m3/s with the average annual water volume being about 4.366 Mm3, while the average annual water volume calculated from runoff was about 4.651 Mm3. Dam 1 is the best-selected site with a suitable index of 97.5 followed by Dam 5, and Dam 2 with a suitable index of 95 and 90, respectively. Hence it falls under the category of highly suitable. The Dam 3 site falls within the modestly suitable category. Finally, the site of Dam 4 could not be established, because they had a suitability index of less than 70.