The present study depicts the hydrochemical processes controlling the variance in the hydrochemical facies for sixteen samples obtained from Habbaniya Lake. The water samples were analyzed for the major ions (cations and anions) data in mg/l, total dissolved solids in mg/l, pH unitless, electrical conductivity in μS/cm, and temperature in °C. Piper trilinear (three-line) diagram indicates the overall of samples belongs to class 1 (Ca2+, Mg2+, Cl-, SO42-), category I (SO42- - Cl- and Ca2+ - Mg2+), and permanent total hardness (calcium chloride type). The contribution of cations in the Habbaniya lake was almost the same percentage (no dominant cation), while the SO42- is the dominant ion of the surface water in the Habbaniya lake. The analytical values showed that overall the samples were freshwater and low enrichment salts within the permissible limits of the World Health Organization standards. Irrigation parameters and water quality index were calculated for samples to assess water for agricultural and drinking uses for the inhabitants of the study area. The basic exchange is the exchange of Na+ and K+ ions in water with Mg2+ and Ca2+ ions in materials which is exposed to weathering.

The present investigation took place at Habbaniya lake to assess the level of pollution as an overall index besides organic directories. Dissolved Oxygen, Biological Oxygen Demand and Chemical Oxygen Demand were calculated for 16 samples of lake water in addition to parameters of Overall Index Pollution. The lake water content of Dissolved Oxygen is excellent and unpolluted according to Biological Oxygen Demand, and Chemical Oxygen Demand values (Dissolved Oxygen varied from 9.100 mg l-1 to 13.600 mg l-1, Biological Oxygen Demand varied from 2 mg l-1 to 7 mg l-1, and Chemical Oxygen Demand varied from 30 mg l-1 to 73.667 mg l-1). Overall Index Pollution was useful and helpful in determining lake water quality. The situation of the lake was better compared to the year 2014. The health status of the lake varied from acceptable to slightly polluted due to having Overall Index Pollution values ranges from 1.632 to 2.677, and it supports aquatic life in it. The map of Overall Index Pollution shows that the values in the northwestern part of the lake are lower than in the southeastern part due to the continuous renewal of water in the first part because it represents a water inlet. This map is almost identical to a distribution map of Dissolved Oxygen, Biological Oxygen Demand, and Chemical Oxygen Demand. In general, Habbaniya lake is non-polluting and not dangerous to the environment now, but it may face the risk of pollution, based on the results obtained. Thus, the present study concluded that the use of the Overall Index Pollution technique with organic indicators is very suitable for assessing the level of water pollution in Habbaniya lake.

Mulussa aquifer extended the area of Rutba-Dhabaa, Western Iraq, has been studied in order to determine the most important chemical functions and interaction between rocks and groundwater (Groundwater–rocks interaction). The results of wet and dry periods indicated that Ca2+ and SO4 2- in the groundwater are the dominant ions. Average of Hydrogen Number (pH), Total Dissolved Solids (TDS), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), chlorine (Cl-), sulfate (SO4 2-), bicarbonate (HCO3 -) and nitrate (NO3 -) are 7.43, 718.25 mg/l, 120.8 mg/l, 40.875 mg/l, 32.865 mg/l, 2.93 mg/l, 103.527 mg/l, 195.9 mg/l, 214.85 mg/l and 4.275 mg/l respectively in the dry period, while its averages 7.33, 664.2375 mg/l, 114.25 mg/l, 35.8 mg/l, 29.28 mg/l, 2.33 mg/l, 90.3 mg/l, 181.1 mg/l, 203.85 mg/l, and 3.6 mg/l respectively in the wet period. The groundwater is characterized by low alkalinity hard to very hard water, between moderately and excessively mineralized water, and fresh to slightly water in both periods. Rock–water interaction processes are indicating that there is a possible contribution of the seawater in Mulussa aquifer, the dominant process is limestone–dolomite weathering, where the source of calcium is rather than gypsum or silicates rocks, and contribution of calcite more than dolomite in the Mulussa aquifer.

Water balance as a technique is considered one of the means that is relied upon in solving significant hydrological problems. The soil and water assessment tool (SWAT) model was used in this study to assess the water balance in the Wadi Al-Mohammadi basin located at the eastern edge of the Western Desert. Digital elevation model, soil data, Land use - Land cover, and climate data represent the most important requirements for the SWAT model's input as a database. The Wadi Al-Mohammadi basin delineation results show the overall drainage area was 2286.8 km2 with seven sub-basins. The trend line of climate data indicates a clear increase in the total rainfall, relative humidity, temperature, and solar radiation from 1990-2020, while the wind speed decreased during the observed period. The average monthly hydrological components (precipitation, actual evapotranspiration, surface runoff, lateral flow, and deep aquifer recharge) representing the basin's water balance are 68.8 mm, 67 mm, 2.03 mm, 0.02 mm, and 0 mm, respectively.

A study was conducted to estimate the Irrigation Water Quality Index (IWQI) for Habbaniya Lake in central Iraq for irrigation purposes. The samples were taken at sixteen stations in October 2019. Studied samples were examined for ten Physico-chemical parameters Hydrogen Number (pH), Electrical Conductivity (EC), Temperature (T °C), Total Dissolved Solids (TDS), Total Hardness (T.H.), Turbidity (NTU), Sodium Absorption Ratio (SAR), Na+, Cl−, and HCO3 −. The results showed that 68.75% of the study water samples fall within the low restriction category (LR) irrigation water in eleven stations (which is dominant in all parts) and 25% of the search region falls under the no restriction category (NR) irrigation water in four stations (which is dominant in the northwestern part at station 5-8). Meanwhile, a small part of the study area represents 6.25% of the water samples is classified as a moderate restriction (MR) irrigation water in one station (in the central part). Accordingly, these categories are suitable to use only with the soil having low to moderate permeability with a plant of some kind for specified tolerance of moderate salts content. The IWQI is homogeneous and suitable for irrigation in all parts, especially the northwestern part which represents the entrance waters through Warar Canal that fed principally from the Euphrates River.