The look for the new water resources and the optimal using of available water is very important because of high change in the climate of the earth, the dry wave in the region as well as the decreases of the water inflow to the Euphrates and the tigress river because of the building of the dams upstream the basin in Turkey and Syria. In the present study, four biggest catchments area in the Iraqi western desert (wadi Horan, wadi AlGhadaf, wadi Ubayiad, wadi Tubul) were selected to study the hydrologic properties to determine the best region for the water harvesting because these areas include the most water harvesting project such as the small dams. Present hydrologic study was depended on the available data to determine the amount of runoff that can be harvested according to measuring data of metrological station in the region with the method of hydrograph for analysis. For the period (1971-1976) the study showed wadi Al-ghdaf is the best region for water harvesting according to the number of floods to the cathment area (44 floods) with water volume (1047*106m3), and the average water harvesting (7098.64 m3/km2). The second is wadi Horan the number of floods to the cathment area (33 floods) with water volume (2033.29*106m3), and the average water harvesting (6115.16 m3/km2). Then wadi al Ubyaid number of floods to the cathment area (21 floods) with water volume (405.197*106m3) and the average water harvesting (2493.52 m3/km2). The last one is wadi Tubul with number of floods to the cathment area (18 floods) with water volume (909.36 and the average water harvesting (2231.6 m3/km2)*106m3)
Wadi Houran is one of the largest valleys in Iraq. Although it is discharging billions of rainfall water over/during many years to Euphrates river, it's almost devoid of agricultural investment. The current study aims to focus on this important valley water resource and study the possibility of constructing a series of small dams to store rainfall water and planting forestry and establishing a natural reserve that is able to sustain and improve ecology system. Target area of 4000 km2 is selected in the midstream of the valley. In general, it is about one billion m3 of rainwater flowing to Euphrates River during some years with yearly average values about 400 Mm3. Four dams were constructed to store about 46 Mm3 of rainwater. It is possible to construct small-dam-series of optimal height and location to expand the rainwater harvesting and groundwater recharging. A Current study was done and aimed to establish of oases and natural reserves in order to improve climate conditions, minimize the dust and CO2, mitigation of summer high temperature and decrease the soil erosion due to torrents. This study recommended constructing 13 optimal height dams that store about 303 Mm3 of water, and increase the water surface area of reservoirs in this valley from 15 to 90 km2which leads increase the water volume that is recharging ground water from 4.7 Mm3 to 28 Mm3 per year.
Dams are considered as the best solution to conserve water especially in arid and semi-arid regions. This study aims to design a small dams series to conserve rainfall water. Mathematical model is proposed to optimize these dams height and locations, its named as Optimal Height And Location Model (OHALM). In this study, new method is introduced to estimate the optimal water level and volume of storage by combining between the digital elevation model generated by the Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) data, and the proposed model (OHALM). Two dams sites were selected for checking the validity of proposed method. The results of the present study showed that the error percentage increase or decrease from reference value by 3.5%, 13% for water level in Al-Rutba dam and Horan 3 dam respectively, and by 6.63%, 35.8% from volume of storage in Al-Rutba dam and Horan 3 dam respectively. The relative error shows a big difference from the actual data, which is a positive percentage for storing additional quantities of rainwater. That means the proposed program is better than the existing dam design, and thus the possibility of using this method to determine the optimal height of the proposed water harvesting sites.
The research aims at revealing the morphometric characteristics of wadi Jbab Basin, which include areal ,relief characteristics, and the shapes of cross- sections of the valley. The hydrological properties of Jbab basin were studied to estimate the amount of water received by its catchment area during rain falls, thus, the appropriate places for the construction of dams and reservoirs for use in water harvesting can be determined. The area under study is located in Iraqi western plateau , between the latitudes of 33º 55' 45"N to 34 º 27' 50" N, and longitudes 41º 24' 30" E to 41º 43' 00" E. Remote sensing technology (RS) and geographic information systems (GIS) were used to reach the objectives of this research, so Digital Elevation model (DEM) for the year 2009 was brought to program (Arc GIS 9.3) and detected the basin and valley of Jbab automatically by using the hydrological analysis method. The area under study is characterized by the drought with a deficit of water in all months of the year where the highest in the month of July, amounting to 324.5 mm and the lowest in January, 10.92 mm. The geological formations prevail formations limestone, with sandy soil to sand-clay mixture, with lack of density in the vegetation. The average slope in basin of Wadi Jbab is 0.25 degree. There are five ranks of river, the sum of their tributaries 676 tributary within an area of 986.6 km ², and its perimeter is 214.3 km , it is also noticed the form of the basin tends to form a rectangle, with three places suitable for the construction of dams and reservoirs depending on the morphometric and hydrologic information that related to the area of research.