OPTIMIZATION STUDY FOR RAINFALL HARVESTING AND ASSESSMENT OF RAINWATER QUALITY IN KORONADAL CITY

This study was conducted to determine the volume of tanks for households that will optimize rainfall harvesting. The study also aims to determine the suitability of rainwater for crop production, domestic use, and drinking in Koronadal City, by the parameters - pH, Salinity, Electrical conductivity Hardness, Turbidity, Total Dissolved Solid, Total Suspended Solid, Nitrate, E.Coli, and Coliform. The data used were daily rainfall from 2014 to 2018, average floor area of residential buildings, total number of households, total population, average water consumption of residents, and water charges in residential establishments. In assessing the rainwater quality, the samples were collected from five barangays in Koronadal City, namely: Barangay Carpenter Hill, Barangay Zone III, Barangay Paraiso, Barangay Avancena, and Barangay Esperanza. Parameters - pH, Salinity, Electrical conductivity, Hardness, Total Dissolved Solid, Nitrate, E. coli and Coliform were analyzed using the Water Hardness/Pure Water Meter, pH Meter, On-site water test strip and Onsite- 3M Petrifilm Coliform Count Plate. Parameters - Turbidity and Total Suspended Solids were tested at Mindanao State University- Diagnostic Laboratory. Based on computations and analysis of computed values, interpretation of figures, and consideration of other important factors ineffectual days, etc.), it is recommended to install a 1.5 m volume water tank in households to optimize rainfall harvesting in Koronadal City. It was found out that the rainwater quality in Koronadal City is suitable for domestic use and for crop production, however is not suitable for drinking considering the method of harvesting and the climatic condition.