In this study, the Dual-Kc approach within FAO-56 paper was applied by water evaluation and planning (WEAP) to get the Kc parameters (Kcb and Ke) and to calculate the water requirement for various soil textures. The results compared with the outputs of Single-Kc approach for summer and winter crops in addition to trees. The results showed when applying Dual-Kc approach, the water requirements was more compared with the Single-Kc approach, except the tomato, eggplant, and Broad bean crop, which decreased by 5%, 4%, and 17% respectively. Also, there was a different in values of coefficient when compare two approaches, it was increased in Dual-Kc approach for wheat by 62% with 20% during initial and end-stage while ranged between 26-58% for trees during all season with more different for other winter and summer crops. The water requirement of crops was different according to soil texture. The net water requirement of wheat was 429 mm and 433 mm for sandy loam and clay loam respectively, with different in irrigation intervals 11 and 12 respectively, while the silt loam was recording water requirement 417 mm with 8 irrigation intervals.

Managing water resources is important with the increasing population, especially in arid and semi-arid regions. It is necessary to treat wastewater and greywater to saving more water amount and increase agriculture density. The current study forecasts the amounts of wastewater and greywater for Ramadi city during the next years (2020-2040). Also, the study proposes the possibility of reusing these amounts as a renewable water resource. These liquid wastes consist of 99.9% water and only 0.1% of solids. The study proposes using the treated wastewater to plant a green belt around the city to reduce the impact of dust storms and use the greywater in irrigating vegetables and fruits. The study was used water evaluation and planning (WEAP) to evaluating water amounts and reused wastewater in the current and future years. The results were indicated the domestic water returns for the current year to Euphrates River is 63 million m 3/year, with 11.7 million m 3/year of greywater, which covers about 22% of Ramadi irrigation requirements. The future domestic water would increase by about 24% to reach 78.4 million m 3/year at 2030 and 95.5 million m 3/year at 2040, while the greywater rising to 21 million m 3/year in 2030, and 34.3 million m 3/year in 2040.

Water is an essential source of sustaining life and used in generating electricity, agriculture, industry, and the daily domestic uses. This study was prepared to determine the water consumption of Anbar Province in the west of Iraq according to agricultural, industrial, and domestic demand. In addition, the study is evaluating the expected future water consumption by demand sites within study area. The results showed the domestic water demand will increases by 32% from 267.30 million m 3 /year in 2021 to 352.70 million m 3 per year in 2035, with a deficit of 24.5% in the year 2035. Furthermore, the study had appeared the agricultural demand was 1404.38 million m 3 /year according to the limited cultivated area, which equals 42.93% from the total available area of 221,250 hectares. The agricultural demand increases to 2611 million m 3 /year when uses all available area, and this cause occurs deficit in water demand reach to 1591 and 1715 million m 3 /year in the years 2030 and 2035 respectively. In contrast, the study referred to necessary apply other irrigation methods as drip and sprinkler irrigation, which has high irrigation efficiency. In addition, using lined channels and pipes to transport water to reduce losses by leaching and evaporation.

In this study, the water evaluation and planning WEAP model was used to improve the Ramadi irrigation project with 28342 hectares and annual budget 326 million 3 / year for the period (2018)(2019). The results showed the total water used was 111.5 million 3 /year and equalled 34.2% of Ramadi irrigation budget. The annual production was 39.3 million Kg/year for Ramadi irrigation, and total economic returns 16.04 million $/year. The study proposal two scenarios to improve the cultivated area. The first scenario increased water volume of the current year from 111.5 million 3 /year to 272.12 million 3 /year, which caused increased in annual productivity from 39.