Evaluating the impacts of landcover change to runoff potential of Tubay river basin through the analysis of multitemporal Landsat images

By Sherwin P. Pulido, Meriam Makinano-Santillan, Jojene R. Santillan

ABSTRACT:

When rain hits saturated or impervious ground it begins to flow overland downhill. Based on observations, changes to land cover can influence the velocity of overland flow. Land use patterns, including increases in impermeable surfaces and construction near riparian zones, affect flow patterns. Increased impervious surface in the areas can reduce the time of runoff and increase the peak discharges of stream flow, resulting in large and more frequent incidents of flooding. Land use within the Mainit-Tubay watershed has undergone changes in the past years. This watershed is located in Caraga region in Northeastern part of Mindanao and has a total area of 994.7292 sq. km. The population has increased and with it, an increase in deforestation and impermeable surfaces. This study evaluated the effects of land cover change to the potential runoff that occurred to the watershed during a rainfall event. The researchers generated land cover maps through the analyses of Landsat images acquired in the years 1995, 2001 and 2014. With this, land cover change was analyzed using remote sensing and GIS techniques. The changes detected were further analyzed to relate it to the changes in surface runoff. Rainfall data during Typhoon Agaton and Typhoon Seniang were utilized to generate runoff depth map. Soil data and curve numbers were added to the land cover maps to generate the runoff volume within the area. Then runoff change was determined. The generated land cover change maps and the runoff change were analyze and evaluated to know the potential effects of runoff change as effect of the changes in land cover. As computed, total runoff volume accumulated in year 2001 was reduced by about 90,894 cu. m. compared during the year 1995. However, a significant increase of runoff volume was detected in the year 2014, in which about 384,000 cu. m. difference from the volume in year 2001 was calculated. This change resulted from the increase in built up, barren and water area which has high runoff potential and in the decrease of shrubs and trees area which has low runoff potential.

KEYWORDS: Surface runoff, land cover, watershed, Landsat


Publication Details/Metadata:

Paper Title: EVALUATING THE IMPACTS OF LANDCOVER CHANGE TO RUNOFF POTENTIAL OF TUBAY RIVER BASIN THROUGH THE ANALYSIS OF MULTITEMPORAL LANDSAT IMAGES

Authors: Sherwin P. Pulido, Meriam Makinano-Santillan, Jojene R. Santillan

Publication Date: 2015

Conference Name/Journal/Book Title: 36th Asian Conference on Remote Sensing 2015 (ACRS 2015): Fostering Resilient Growth in Asia

Volume: 5

Pages: 3435-3442

Publisher: Asian Association on Remote Sensing

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