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ANALISIS KERAWANAN BANJIR MENGGUNAKAN METODE NORMALISED MORPHOMETRIC FLOOD INDEX (NMFI) SSTUDI KHUSUS : SUB-DASAR AIR MANNA, BENGUKULU SELATAN

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Several factors, including climate, land use and cover types, rock lithology, geomorphology, and hydrological conditions of an area, influence flooding. The research location is the Air Manna watershed, which is administratively located in Ulu Manna District, South Bengkulu. This research aims to identify the influence of morphometric aspects on the potential for flooding in the watershed and map the flood disaster vulnerability area. The data used are primary and secondary. Primary data in the form of lithology-type data to support the results of the analysis of flood disaster potential in the research area and secondary data in the form of Digital Elevation Model data, NDBI (Normalized Difference Built-Up Index) data, NDVI (Normalized Difference Vegetation Index) data and SHP RBI land cover of South Bengkulu Regency. After analyzing the morphometric parameters, it was found that some areas in the Air Manna sub-watershed have a high flood potential. These areas have high drainage density values, high main channel slope, low length of overland flow, high ruggedness number, and low bifurcation ratio values. The overlay map of the Air Manna sub-watershed flood potential results from processing NMFI values converted into polygons. A polygon is a vector data type used to describe an area. Furthermore, the results of the morphometric parameter analysis of the research area will be normalized using the Normalized Morphometric Flood Index (NMFI) method. NMFI simplifies morphometric parameter analysis results into the range of 0.00 - 1.00, which aims to reduce the analysis results' subjectivity and increase the analysis data's accuracy. Based on the results of NMFI processing, three levels of flood hazard are obtained, namely low, medium, and high, on the map, which is depicted in green, yellow, and red colors. The results of the analysis of morphometric parameters are supported by morphological characteristics in the form of tight hills in the Air Manna river basin, with a relatively low level of infiltration and permeability based on the relationship of the soil permeability coefficient to the infiltration rate. The soil permeability coefficient is the capacity of soil to pass water. Soil with a high permeability coefficient can increase the infiltration rate and reduce the rate of runoff water. In the research area, the soil type is dominated by fine sand-medium sand with a permeability coefficient of 0.125 - 0.50 cm/sec; the permeability coefficient value is included in the infiltration rate class prolonged instead of slow. Areas with low hazard levels amounted to 5.98% or 2009.75 km2, medium hazard levels amounted to 80.09% or 26916.64 km2, and areas with high hazard levels amounted to 13.92% or 4678.23 km2. Areas with high flood potential points include Simpang Pino Village, Merambung, Bandar Agung, Batu Kuning, and Batu Panco.

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Detail Information

Series Title

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Call Number

T1579352024

Publisher

Indralaya : Prodi Teknik Geologi, Fakultas Teknik Universitas Sriwijaya., 2024

Collation

xviii, 151 hlm.; ilus.; 29 cm

Language

Indonesia

ISBN/ISSN

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Classification

551.480 7

Content Type

Text

Media Type

unmediated

Carrier Type

-

Edition

-

Subject(s)

Prodi Teknik Geologi
Kerawanan Banjir

Specific Detail Info

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Statement of Responsibility

TUTI

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