APPLICATION OF WATER QUALITY INDEX (WQI) FOR AGRICULTURAL AND IRRIGATIONAL USE AROUND OKPOKO, SOUTHEASTERN NIGERIA

• Main Authors: Ememu, Nwankwoala
• Format: Article
• Language: English
• Published: Zibeline International 2018-01-01
• Series: Engineering Heritage Journal
• Subjects: Groundwater; water quality index; agriculture; irrigation; salinity hazard
• Online Access: https://www.zibelinepub.com/archives/1gwk2018/1gwk2018-14-18.pdf.pdf

This study aims at using the water quality index (WQI) in the assessment of groundwater for agriculture and irrigation purposes. This was possible with the aid of several water quality indices including Sodium Adsorption Ratio (SAR), Magnesium Adsorption Ratio (MAR), Sodium Percentage (Na %), Permeability Index (PI), Residual Sodium Carbonate (RSC), Kelly’s Ratio (KR) and Potential Salinity (PS). All the quality indicators show that the groundwater sources in the area are excellent for irrigation purposes. In this study, electrical conductivity (EC) ranges from 3.20 to 139.32 mg/L with mean and SD values of 47.32±45.20 mg/L. Based on Richard’s classification scheme, the groundwater sources are of low salinity hazard (< 250 mg/L), hence, excellent for irrigation purposes. The values of SAR in groundwater from the study area range from 0.1 to 0.89, with mean and Standard Deviation (SD) of 0.41±0.28. SAR values less than 3.0 will not threaten vegetation while values above 12.0 is considered sodic and will threaten plant survival by increasing soil swell potential and reducing the permeability of soil. The results of SAR in this study indicates low sodium hazard for all the groundwater sources. Evaluation of water quality for agricultural purposes using SAR, Na %, RSC, PI, SP, and Kelly’s ratio suggests that they are suitable for agricultural purposes. Water Quality Index implies that most of the areas around the area were dominated by the good to excellent quality water for different purposes. In addition, the results of this study will be useful in estimating the major sources of contamination in different areas within the framework of activities intending to improve the quality of water. Water Quality Index (WQI) ultimately helps us to understand the water quality in surrounding areas. Moreover, it will be helpful in monitoring activities and for further water quality management to prevent the pollution.