Incorporating bridges in the streamflow analysis of Cagayan de Oro River

Flooding is one of the most threatening natural disasters in Cagayan de Oro. With floods causing property damage, health hazards, and even loss of life it is apparent that flooding is an issue of pressing urgency for the citizens thereby, making it evident to address and overcome its causes. Several...

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Bibliographic Details
Main Authors: Concepcion, Vincent Marion R., Garcia, Allan Paul S., Lapena, Emmanuel D., Jr., Sulicipan, Stephen Gil G.
Format: text
Language:English
Published: Animo Repository 2018
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Online Access:https://animorepository.dlsu.edu.ph/etd_bachelors/6425
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Institution: De La Salle University
Language: English
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Summary:Flooding is one of the most threatening natural disasters in Cagayan de Oro. With floods causing property damage, health hazards, and even loss of life it is apparent that flooding is an issue of pressing urgency for the citizens thereby, making it evident to address and overcome its causes. Several studies have aimed to lessen the flood that are happening in the area, however, none of these have focused on the effect of bridges. This study determined constrictions that bridges make into flooding under a given rainfall scenario. The study developed watershed model and floodplain model that were simulated under 5, 10, 25, 50, and 100-year rainfall return period along Cagayan de Oro River. Using different GIS software tools, the digital elevation model was preprocessed to visualize the watershed and floodplain area. The researchers simulated the flow under different rainfall return periods. HEC-HMS was used to simulate rainfall in the upper catchments tributary to Cagayan de Oro City and shall provide as inflows to the Cagayan de Oro River. Flow and depth patterns, profiles were obtained for the adjacent floodplain. Each rainfall return period was simulated with bridges and without bridges. Bridges that were included in the investigation were Carmen Bridge, Jr. Borja Bridge, Marcos Bridge, Puntod Kauswagan Bridge, and Pelaez Bridge. Comparing the results of simulations with and without bridge for different rainfall return period, it can be observed that the inclusion of bridges caused the depth on the river to rise up when the rainfall return period is as high as 25-year rainfall return period. Furthermore, in terms of the area bounded by the water, the bridge did not have much effect when the rainfall return period is low as 10-year return period. 5-year and 10-year return periods resulted to 1.2% and 1.95% compared to 25-year, 50-year, and 100-year return period, which resulted to 13.28%, 16.81%, and 12%., respectively. After analyzing the results, flood hazard map for each rainfall return period was generated assimilating the effect of each bridge.