Irrigation and Drinking Water Quality Index Determination for Groundwater Quality Evaluation in Akoko Northwest and Northeast Areas of Ondo State, Southwestern Nigeria

Olumuyiwa Olusola Falowo

doi:10.11648/j.ajwse.20170305.11

Abstract

In order to understand the suitability of groundwater for drinking and irrigation purposes in Akoko northwest and Akoko northeast, water quality index calculation, % Na, Sodium Absorption Ratio (SAR), Residual Sodium Carbonate (RSC), Permeability Index (PI) and Electrical Conductivity were determined from thirteen water samples. The sequence of the abundance of the major ions is in the following order of K+ > Na+ > Ca2+ > Mg2+ for cations and Cl- > HCO3- > SO4- > F- in anions. The water quality index (WQI) obtained for the water samples ranges between 22.7 and 88.6. The water quality index classified the water into “excellent” and “good” drinking water and account for about 85% and 15% of the study area respectively. The % Na of the samples varies between 49 and 79%. Sodium Absorption Ratio (SAR) of the studied water samples varies from 1.40 to 3.56 with a mean of 2.44. The values are within 0 - 10 specified as excellent water for irrigation purpose. The Residual Sodium Carbonate (RSC) values ranges between – 51.6 and + 10.57, with an average of -14.5, which agrees with less than 2.5 specified for the purpose of irrigation. The permeability index (PI) of the water varies from 2.27 to 19.9, with an average of 7.93. The values fall within the Third category of 0 – 25 irrigation water which is rated as poor. The electrical conductivity of the water ranges from 117 to 789 μs/cm with an average of 378 μs/cm which corresponds to moderate (medium salinity). Also, the water in the study area shows variation of low salinity to high salinity. The Wilcox plot showed that the water samples have excellent – good irrigation potential except a sample taken from Arigidi Akoko which fall within “good to permissible limit.” Therefore combine all these results the water are moderately suitable for irrigation purpose and good for drinking.

Highlights

Three fourth of the earth’s surface is covered by water
Thirteen (13) water samples were collected from seven boreholes and six open - hand pump operated water wells were collected in the study area “Figure 2”
The sequence of the abundance of the major ions is in the following order of K > Na > Ca > Mg for cations and Cl > HCO > SO > F in anions

Summary

Introduction

Three fourth of the earth’s surface is covered by water. In spite of this apparent abundance of water, less than one percent is available for human use in the form of surface water as 97 percent is contained in oceans etc. When ground water becomes contaminated by the dissolved elements and gases and by presence of suspended solids, bacteria, and viruses, it is difficult and expensive to clean up. Such water is no longer fit for a specific use, such as drinking, the water is said to be contaminated. If the water becomes heavily contaminated it is said to be polluted [2]

Objectives

Methods

Results

Conclusion