Vulnerability assessment of Taft River Watershed [in Samar Island, Philippines] conducted

Taft River Watershed in Samar Island [Philippines] is one example, which shows conditions characterizing vulnerability. Hence, Nasayao et al. (DENR-ERDS 8) conducted the vulnerability assessment of the Taft Watershed to: 1) identify and determine relative priority hazards in the watershed; 2) identify critical factors affecting its vulnerability; and 3) recommend specific measures for formulating policies. This is to mitigate possible damages, improve the current state of the watershed, and increase their adaptation capacity. Findings of the study revealed the following: The watershed was found to be substantially a karst region with sinkholes and underground channels. Parent materials were generally metamorphic, with limestones abounding in the area. Soil was calcareous in elevated and mountainous areas. In lowlands, however, soil was mostly acidic exhibiting clayish texture. In the upstream portions, particularly the mined out areas of Bagacay and Hinabangan in Samar, results of soil analysis showed that the physical characteristics of the soil varied from clay loam to sandy loam, sandy loam to sand. Chemical characteristics of the soils, on the other hand, showed that almost all soil samples had ultra acid to extremely acid pH of as low as 2.290. Areas with high pH were mostly vegetated indicating the importance of soil pH in establishing vegetation in the abandoned area. Results also revealed the total nitrogen and exchangeable calcium were both very low to extremely low. Exchangeable phosphorous was low to very low based on reported values while exchangeable potassium values were high to extremely high. Taft River Watershed was highly diverse, particularly, in areas with forest cover. It was a repository of 254 species of vascular plants, 16 species of amphibians, 20 species of reptiles, 77 species of birds, and 23 species of mammals. The project is still being conducted and aims to: 1) have an updated and credible information regarding the state of the Taft River Watershed; 2) be a mechanism or a management tool for making sound decisions and formulating policies on appropriate land use disaster mitigation and conservation measures of concerned agencies; and 3) inform or educate people and communities on the actual and potential hazards affecting watersheds.