ASSESSMENT OF GROUNDWATER QUALITY FOR IRRIGATION AT MALAMAWI ISLAND, BASILAN, PHILIPPINES

Abstract

The assessment of groundwater quality for agricultural purposes was conducted in Malamawi Island, Isabela City, Basilan. Groundwater quality wasevaluated based on the FAO irrigation quality standards (1994)which include salinity and alkalinity, sodium, magnesium, bicarbonate hazards and chloride hazards. Spatial delineation of groundwater quality parameters was carried out using QGIS software. Results revealed that the use of groundwater from two separate sampling wells (SW4 and SW6) in Lukbuton area require slight to moderate restrictionbased on the parameters of electrical conductivity and magnesium hazard. This means that its groundwater can still be safe for irrigation but with little salinity hazard on sensitive crops.Also, the chloride concentration in SW4 indicates that groundwater was slightly poor in quality but generally suitasble for irrigation while in SW6, the calcium concentration was considered unsuitable for irrigation. In the same way, the sampling wells 1 and 3 in Santa Barbara and Lukbuton were considered unsafe and unsuitable for irrigation in terms of magnesium hazard. Also, the calcium content of groundwater in some part of the island was considered unsuitable for irrigating high-value crops. Therefore, this study suggests that some management is needed in the northeastern part of Lukbuton because of its poor ground water quality for irrigation in terms of salinity.