Keywords : Contour map
journal of kerbala university,
Volume 8, Issue 4, Pages 204-222
In the current study, the contour maps of contaminants parameters distribution and the analysis of the chemical quality of groundwater in the Karbala region have been carried out to evaluate the suitability of water for drinking and irrigation purposes. The study based on the observed groundwater data of 155 unconfined wells represented the area. These data have been analyzed and contoured for the hydrogen ion concentration (PH), the concentrations of the major cations Na+, Ca+2, Mg+2,K+and the anions SO4-2, Cl-, HCO3-, NO3-, the electrical conductivity (EC), the total dissolved solids (TDS) and the total hardness (TH), and they are compared with WHO and Iraqi standards. Only 140 wells were used for contour maps calibration and the remainder 15 wells were used for verification. The results showed good correlation between the observed and estimated data. The water quality index (WQI) was used to evaluate the groundwater for drinking uses. Based on WQI, it is found that 58.7% of the Karbala groundwater is unsuitable for drinking uses. The assessments were also achieved for the important constituents’ parameters affecting the water quality for irrigation such as the sodium adsorption ratio (SAR), the sodium percent (% Na), the permeability index (PI) and the magnesium hazard (MH). A correlation matrix was built to evaluate the degree of correlation between any two chemical parameters. Two methods were applied to evaluate the suitability of Karbala groundwater data for irrigation purposes. The first one is the US salinity diagram (1954) and the second one is the Wilcox classification diagram (1955). Based on USSD, 58.7% of the Karbala groundwater data are classified as (very high salinity hazard – medium sodium (alkali) hazard) (C4-S2). Depending on the WCD, 73.5% of the Karbala groundwater data are found unsuitable for irrigation. According to the mean value of PI and MH, the Karbala groundwater data are found permissible for irrigation purposes.