Assessment of the hydrologic and economic impacts of extreme climate events in Manupali Watershed, Bukidnon, Philippines

The hydrologic and economic impacts of extreme climate events (ECes) were assessed at the Manupali Watershed in Bukidnon. Two climatic events were evaluated and compared to the 1996 normal year-the 1998 El Nino climatic event and the 1999 La Nina climatic event. For the hydrologic component, the study was focused on the runoff and soil erosion (sediment yield, soil loss and soil loss depth). The SEA-BASINS model was used to simulate runoff while the Modified Universal Soil Loss Equation (MUSLE) model was used to estimate for the soil erosion. With regard to the economic component, the assessment was focused on the change in the crop (corn, and coffee) profitability using cost-and-return analysis, and production function analysis. Valuation was also done to translate into monetory value the impacts of ECes. During the normal condition in 1996, the average runoff and soil erosion in the Manupali watershed was already high. The production of corn was relatively good but the production of coffee was not. With the presence of El Nino in 1998, runoff decreased significantly but there was just a slight decrease on the soil erosion. Corn was adversely affected but production of coffee increased during this year. Corn obtained a loss of P4,485.69 per hectare while coffee earned a positive net income of P5,377.57 per hectare. Regression analysis for coffee showed that El Nino event significantly affected the production of coffee. On the average, on-site cost was valued at P4,372.00/ha for corn, while the on-site profit was valued at P20,418.00/ha for coffee during El Nino event. During the 1999 La Nina, there was a significant increase on the runoff and soil erosion. During this event, corn also obtained a net income loss of P912.06 per hectare. On the contrary, coffee earned an income of P5,988.92 per hectare. On the average, on-site was valued at P1,793.00/ha for corn, while the on-site profit was valued at P16,671.30/ha for coffee during La Nina event. The study shows that the 1998 El Nino and 1999 La Nina significantly affected the hydrology and ecology (on farm level) of the Manupali Watershed. Thus, appropriate and effective measure to cope with and minimize the adverse impacts of ECes are necessary