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Asian Journal of Agriculture and Development (AJAD) - Call for papers!

Landscape Dynamics and Hydrologic Changes in Mananga Watershed, Cebu, Philippines

(Philippines), Doctor of Philosophy in Environmental Science (University of the Philippines Los Baños)

Dissertation Abstract:

 

The change in landscape structure and its influence on the hydrology of Mananga Watershed in Cebu Province were assessed. Land use maps in 1956, 1985, and 1995, together with topographic and other thematic maps, were used to identify and delineate the common landscape elements. ArcView 3.2 was used to analyze changes in patch size, number, density, and landscape pattern with respect to soil type and slope of the watershed. The temporal change in runoff coefficient and soil erosion potential was determined. Actual runoff coefficient was compared with estimated runoff coefficient using Soil Conservation Service Curve Number for estimated runoff. Soil infiltration rate was determined for different land uses and soil types. The influence of change in population of the watershed was also assessed.

The watershed landscape consisted of a matrix of annual cropland; patches of tree plantation, brushland, grassland, and perennial cropland; and river and road corridors. The area for annual cropland had decreased continuously throughout the period studied (1965-1995) while tree plantation’s area had increased throughout this period. This contributed to the downward trend in runoff coefficient. The proclamation of the watershed as protected area and the reforestation activities improved watershed hydrology.