KAJIAN LUAS GENANGAN DI WILAYAH RENTAN BANJIR PADA SUB DAS KARANG MUMUS DITINJAU DARI PETA KEMIRINGAN LERENG DI KOTA SAMARINDA
Research objectives to predict the extent of flood inundation in Samarinda. The benefits of this research can provide a broad picture of flood inundation in the city of Samarinda. Biophysical conditions in Karang Mumus Sub-watershed for Sub-districts that are vulnerable to flooding, North Samarinda Subdistrict slope 0-8% with area of 12,356.3ha of 31.0265%, slope of 25-40% grade of steep slope with area of 269.2ha of 0.6760%, slope> 40% grade of very steep slope with an area of 12.7 ha of 0.0319%, and inundation area of 1.506ha of 55.72%. For Sungai Pinang district, the slope of 0-8% is flat slope class with an area of 1,592.7ha of 3,9992%, and inundation area of 473ha of 17.5%. For Samarinda Subdistrict City slope 0-8% class flat slope with an area of 292.9ha at 0.7355%, inundation area 148ha at 5.48%. North Samarinda Region, based on the inundation map area of 1506ha (55.72%) and based on the topographic map / slope 0-8% grade of flat slope of 12,356.3ha (3.0266%) so that the slope greatly influences the size of the inundation area. On the slope of 8-15% the slope grade is 4,141.2ha (10.3985%) and based on the inundation map area of 1500ha (55.72%). On the slope of 15-35% the slope class is rather steep at 1,831.6ha (55.72%). On the slope of 25-40% the grade of the steep slope is 269.2ha (0.6860%). The total area of North Samarinda based on a topographic map / slope of 1,860.2ha and inundation area of 1506ha of the total area of North Samarinda that was not flooded by (1,860.2 ha-1,506ha) = 354.2ha of area not flooded around 354.2 / 1860.2 = 19.04%, so that the North Samarinda area is vulnerable to flooding, so civil engineering actions are needed. Samarinda City Region, based on the inundation map area of the City of Samarinda, an inundation area of 148ha (5.48%). On the topographic map / slope for the slope class 0-8% slope class 0-8% flat slope class is 292.9ha (0.7355%) and for areas that are not flooded by (292.9-148ha) = 144, 9ha (49.47%), and for flooded areas by 50.53%, so that Samarinda City is a flood-prone area that requires civil technical action. In connection with the potential for flood prone areas in the Karang Mumus Sub-watershed, it is necessary to implement technical civil measures such as normalizing river channels including drainage networks, optimizing water catchment areas and water catchment areas. Utilization of space for activities outside the allotment of land must be reviewed, policing and law enforcement must be carried out with the aim of maintaining environmental balance but implementation in the field there are still many obstacles related to culture and characteristics of the area so that it needs to be disciplined mining and settlement regulations are land uses that have a major impact increasing flood concentrations in urban areas.
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