Analysis of the Impact of Land Use Change on Flood Discharge in the Ameroro River, Konawe Regency

Situated in Konawe Regency, Southeast Sulawesi Province, the Ameroro Sub-watershed forms a part of the river basin landscape, an area marked by recurrent flood incidents attributed to escalating rainfall intensities in Konawe Regency. Over time, the Ameroro Sub-watershed has witnessed shifts in its land utilization dynamics, transitioning from its initial dominance of forested expanses to a diverse composition of plantations, rice fields, open terrains, and settlements. This alteration in land use stands as a contributing factor to the occurrence of flooding, evident in the changes in land use change parameter, the curve number (CN). The primary objective of this study is to ascertain the values of runoff coefficients and flood discharge across the review years that coincide with the shifts in land use. This study uses SCS-CN method for predicting direct runoff or discharge from rainfall excess of ungauged watershed and Snyder Unit Hydrograph. The hydrological analysis leverages the HEC-HMS tool for its investigative purposes. The examination of land use transformations hinges on data extracted from 2014, 2018, and 2022 within the Ameroro Sub-watershed, facilitating a comprehensive juxtaposition of flood discharges for each corresponding year. The findings of the analysis elucidate an upward trend in curve number (CN) values over the temporal scope. The analysis results indicate a 3% increase in flood discharge within the Ameroro Sub-watershed between 2014 and 2018, followed by a 7% increase from 2018 to 2022. Over a period of 9 years, from 2014 to 2022, there was a cumulative increase of 10% in flood discharge.