Flood Mitigation in Banjar Regency, South Kalimantan, Indonesia in 2021: Between Hydro-meteorological factor and Anthropogenic factor

Abstract

The year 2021 in Banjar Regency and several other regencies in South Kalimantan Province opened with floods disaster. High rainfall caused the river to overflow; one of the rivers that overflowed was the Martapura River in Banjar Regency. The flood in 2021 is not the first flood disaster to occur, but a floods disaster that has occurred frequently. This flood is a fairly large flood compared to the previous flood. The areas affected by the large flood in Banjar Regency are in the Districts of Sungai Tabuk, Martapura Kota, East Martapura, West Martapura, Astambul, Karang Intan, and Pengaron. The method used in this research is to analyze the hydro-meteorological using the rainfall-runoff model, and the anthropogenic factors in the flood events in Banjar Regency be approached by the value of the C coefficient. The hydro-meteorological factors as natural factors cannot be predicted. The extreme rainfall on January 14, 2021 as 255.3 mm is higher than 100-years return period as 244.716 mm. Its caused biggest flood disaster in January 2021. The anthropogenic factors caused by humans can be reduced. One of the anthropogenic factors that have the most impact on any flood event is land-use change. Land-use change causes rainwater that falls cannot infiltrate into the ground. One of the most common community activities is to close the yard and the drains so that rainwater does not have access to penetrate the ground. Second, the conversion of agricultural land, and swampland into residential and industrial areas. The third factor that is no less important is the role of the community in development that is not environmentally friendly, one of them by dredging for houses or other buildings. These three anthropogenic factors cause the C value to increase, and it increases the flood discharge.