Water Quality Assessment of Different Land Uses of Tugbo Watershed Forest Reserve and Downstream River

Abstract

Changes in land use and management practices have been highlighted as one of the main driving forces behind risks to the quality of the water in the Tugbo watershed and downstream river in Masbate Island, Philippines. The purpose of the study is to evaluate and analyze pertinent data regarding the impact of various land uses on the tributary physicochemical properties of the river both on- and off-site using data from water quality monitoring and the DENR Administrative Order (DAO) No. 2016-08 classification guidelines for water quality. Six (6) types of land cover predominate in the watershed: pastureland, agroforestry farms, old-growth forests, coconut-based areas, built-up/quarry sites, and built-up/estuaries were identified.   Significant differences at 0.05 level were observed based on Analysis of Variance (ANOVA) and post-hoc test results across different land uses are significantly different from each other between the inside and outside the watershed.  The data show that pH and nitrate are significantly different water quality outcomes in comparison to the LULC of the test site, regardless of the land cover or land use adjoining the water system. Other than two land-uses differences, the temperature and dissolved oxygen do not differ greatly from one another. Analyses of the water quality were within the norm, and a positive correlation was found between several indicators and various land uses. The outcome is generally highly beneficial for developing and implementing watershed strategies to protect land and water resources and improve the overall state of the continuum.