National Research and Development Project for Watershed Management Saug Watershed in Davao del Norte and Compostela Valley Province [Philippines]

Date

2023

Abstract

This three-year study was implemented in Saug watershed from April 2012 to December 2014 to determine the physical, biological, socio-economic characteristics, vulnerability assessment and instrumentation as to climatic and hydrological condition of the watershed. Results of the physical study showed that Saug watershed had an area of 99.871 hectares encompassing 9 municipalities, one city and 85 barangays [villages] within Davao del Norte and Campostela Valley provinces. Results of the water quality study showed that water pollution is affected by various land uses. Higher pollution with lower water pH, lower DO, higher conductivity and higher salinity were observed in stream tributaries were land uses were annual crops such as rice and banana compared with streams with perennial crops such as coconut brushlands/grasslands and secondary forest as land use. Results of the soil erosion rate study showed that for napier grass was more effective in controlling soil erosion at 5 tons per ha/yr compared to string beans with 6 tons/ha/yr and the bare uncultivated plot (control) with 8 tons per ha/yr. Biological survey showed that for overstorey floral species, low species diversity at 0.67, 0.89 for understorey species and 0.61 for regeneration species. The avifaunal survey show 76 individuals of birds from 12 species were recorded during the dry season and 44 individuals from 11 species during the wet season. Only 2 species of mammals and one reptile species were observed. Arthropod survey showed high species diversity (3.17) during the dry season than the wet season (2.6). A total of 991 species from 7 taxonomic classes, 22 orders and 97 families were recorded. Fungal survey showed low diversity index of 2.11, 1.84 and 2.06 in forest, agroforest and open brushland consisting 4 classes, 7 orders, 13 families and 84 species. The existing biomass was computed at 25.51 tons per hectare and the carbon stock was 12.75 tons per hectare. Socio-economic profiling showed a high population of the watershed with a total of more than one fourth of a million people at 263,634 people per 2010 NSO data. About 98.82% are literate while the rest are illiterate. Farming is the main occupation comprising 34.31% of respondents while the laborers comprised 13.40%. More than 89% were below poverty line. About 15,573.62 hectares or 15.60% of Saug watershed is vulnerable to flood while many areas are vulnerable to landslides while downstream rivers are prone to water pollution.

Language

English

Document Type

Article

Pages /Collation

246 leaves

En – AGROVOC descriptors

WATERSHED MANAGEMENT; WATERSHEDS; WATER QUALITY; WATER POLLUTION; LAND USEBIODIVERSITY; ARTHROPODA; FUNGI; PHILIPPINES

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