Physicochemical Characteristics of Water in the Bontanga Irrigation Dam in the Guinea Savannah Agro-Ecological Zone of Ghana

Abstract

Fresh water resource is one of the most significant natural assets of a country.  Irrigation dams are usually used for irrigation purposes and also often serve as a source of water for domestic use. Due to this, there is a need for proper maintenance, assessment, and sustainable use of irrigation dams. This study assessed the physicochemical properties of the water in the reservoir of Bontanga irrigation dam situated in the Guinea Savannah Agro-Ecological Zone of Ghana. The study assessed four (4) physical and fourteen (14) chemical water quality parameters of the water for irrigation to know whether they are within the acceptable threshold set by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). Sampling techniques used in this study were stratified and purposive samplings. The reservoir of the dam was divided into nine (9) strata and in each stratum, 5 samples were taken making a total of 45 samples. Samples taken in each strata were composited making it a total of 9 samples. The water samples were collected into well-labelled polythene bottles and kept in an ice chest with ice cubes. The samples were transported to the Ecological Laboratory of the University of Ghana for analysis. The parameters analyzed were pH, electrical conductivity (EC), temperature, total dissolved solutes (TDS), chloride (Cl-), sulphate (SO42-), bicarbonate (HCO3-), carbonate, PO4-P, nitrites/nitrate (NO3-N), total dissolved solids (TDS), magnesium (Mg2+), calcium (Ca2+), sodium (Na+), boron, total alkalinity, ammonia (NH4-N) and potassium (K+). A greater percentage of the results obtained were within acceptable limits except potassium which was slightly higher. This could be the result of farming activities in the catchment of the dam. In general, the water in Bontanga irrigation dam can be considered suitable for irrigation purposes.