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Climate change causes water shortage (water scarcity) in addition to the dams built by neighboring countries, which caused a lack of Iraq's water share. Therefore, evaluating the irrigation system requires considering its suitability, adequacy, and efficiency. Irrigation is considered adequate when it maintains water availability within the root zone, and if the amount to be added is determined, irrigation efficiency becomes possible by avoiding water loss. Babil Governorate is considered one of the agricultural governorates in the country that depends on its irrigation from Shatt Al-Hilla. The study area is the Elaj project. Three fields were selected for the project (B1, B2, and B3). These fields are located at the project's beginning, middle and end. The evaluation was based on the field measurements of water contents before and after watering during the growing season. Also, the root zone of each plant during the growing season is measured to give more accurate calculations. Accordingly, application efficiency, conveyance efficiency, distribution efficiency, storage efficiency, water productivity efficiency, and water use efficiency were calculated in the project. The application efficiency for the selected fields ranged between (33 to 39) % in B1, (32 to 38) % in B2, and (32 to 39) % in B3. The application efficiency in all fields increased by about 6% during the third watering period between (22/3/2021 to 4/4/2021) due to the low water level in Shatt Al-Hilla during maintenance work that lasted more than a month. The efficiency of the scheme [ηs%] in the project is 32.3%. This value is low and reflects the reality of irrigation in the Babil. Therefore, improvements must be made to the irrigation system.

The pumping station is widely used in our modern life. The occurrence of the vortex at pumpsump, which is causing air entering pipe intake, is a common problem in the design of pumps. Thisphenomenon, including surface and sub-surface vortex, may lead to damage to the pumping structure, highpower consumption, and loss in pump performance. In some requirements, the multiple suction pipes areusing to get the required flow. Due to this arrangement, the performance of the suction pipes will influence.This paper is aimed to investigate the occurrence of vortices around the flow pattern of two pumps by usingComputational Fluid Dynamic (CFD) code Fluent. This CFD model is based on solving Navier-Stockequations by finite volume method. The model of double suction pipes was investigated under five differentsubmergence depth (S) and five different suction velocities (v). The SST k-ω turbulence model was selectedfor the turbulence. The results showed that the air entering vortex does not appear when the submergencedepth (S) is equal or greater than 1.5 times from the diameter of the bellmouth for intake pipe (D). Thesurface vortex appeared obviously when the submergence depth (S) equals to 1.25D and the Froude numberat the bell is equal to or greater than 1.028, and appeared clearly when the (S/D=1) and Froude number isequal to or more than 0.77. The nearer attached wall vortex does not appear when the space from the centerof the suction pipe to the sidewall (C) equals 2 times of bell diameter.

Euphrates River extends about 125 km within the study area located in Annassiriyah City, Dhi Qar Governorate, Iraq. The impact of the seven hydraulic structures on the discharge capacity of the Euphrates River needs to be considered. The main objectives of this research are to increase the discharge capacity of Euphrates River within Annassiriyah City during flood seasons and study the impact of these hydraulic structures on the river capacity by using HEC-RAS 5.0.3 software. Five scenarios were simulated to study the different current condition of Euphrates River within Annassiriyah City. Other additional four scenarios were implemented through river training to increase the river capacity to 1300 m³/s; it is the flood of 100 year return period. The results of the current condition showed that the maximum discharge capacity of Euphrates River within Annassiriyah City is just 300 m³/s. The results of applied improvements show that the capacity can reach 1300 m³/s when Al Chibayish Weir was hypothetically removed from the river system. Additionally, the river capacity will be reduced to 600 m³/s when Al Chibayish Weir is considered. It was concluded that the 100-year flood discharge cannot be achieved without removing Al Chibayish Weir from the river system.

An evaluation the performance of the irrigation system for the Al-Ishaqi irrigation project for the Eastern Canal was conducted to identify management strategies that can be used to improve the operation and performance of the irrigation system. The study area is located in Salah al-Din G.0overnorate, Iraq. The field work included determining the moisture content of the soil before and after irrigation, measuring the inflow of the field to find the depth of the applied water, field monitoring, and measuring the depth of the root zone for each irrigation process. Field measurements showed that the average efficiency of water application for the two fields (A, and B) are 59.81% and 38.6%, respectively. The results of the efficiency of water application showed that farmers use water more than the actual demand, so it was possible to increase the efficiency of field water use by controlling the quantities of water that supplied and controlling the irrigation time and water distribution within the irrigated land. The results also showed that the storage efficiency of the two fields (A, and B) ranged between (39.1% to 68.28%), and (41.80% to 79.8%), respectively. As for the efficiency of water distribution, the average distribution efficiency for fields (A) and (B) was about (99.54%) and (99.33%), respectively. The irrigation efficiency evaluation done in the Al-Ishaqi Irrigation Project revealed that farmers utilize more water than is required, resulting in a substantial amount of water being lost in the fields observed in this research owing to inefficient use. If the current scenario continues, groundwater levels would undoubtedly rise, putting the irrigation system's long-term viability in jeopardy.

Low incoming discharge upstream of Samarra-Al Tharthar System leads to sediment accumulation and forming islands, especially an island upstream of Al Tharthar Regulator. This island and the sedimentation threaten the stability of the structure and reduce the efficiency of the system. This study aims to hydraulically identify the sedimentation problem mentioned above, to find solutions of how to control the sediment problems, and to develop the capacity ofthe system for 500 years return period flood of 15060 m3/s. Surface Water Modeling System (SMS10.1) with two dimensional depth average models (RMA-2) software were used to simulate and analyze the system. The results of analysis showed that the maximum permissible discharge through the system was 8250 m3/s where the discharge from Samarra Barrage was 2400 m3/s to avoid flooding in Baghdad city. The water surface level could be lowered during constructing;the new Al Tharthar Regulator expansion capacity of 7000 m3/s in the case of peak flood (15060 m3/s) to 68.51 m.a.m.s.l. upstream of Samarra Barrage by dredging the island and channel. On the other hand, during constructing the guide bank, and dredging the island and channel, the water surface elevation was 68.91 m.a.m.s.l. upstream of Samarra Barrage.

The Makhoul Dam project proposed to be established is considered one of the strategic projects in Iraq as it works to insurance large quantity of water spare in flood seasons, increase the storage capacity of the dams in Iraq, as well as increase food security. The Makhool Dam is located on Tigris River in Salah al-Din Governorate, and 8 km south of the meeting point of the Tigris River with the Lower Zab River. The lake area is about 256 km2. In this research, a mathematical model was prepared by using HEC-RAS Two Dimension Software to analyze the velocity patterns and water depths inside makhool dam reservoir at the highest operational water elevation, based on the designs prepared by the Iraqi Ministry of Water Resources which is 150.25 m.a.s.l. The present study was conducted to investigate velocity patterns with the difference outlet discharges and changing the operation of the spillway gates within Makhool reservoir. The velocities were predicted and evaluated by utilizing modeling efficiency was 99.7%. This shows that the velocity distribution can be described the pattern with a good accuracy. The obtained velocities were ranged from -0.5 m/s to 5.1 m/s, the maximum velocities were near the dam axis.