Pemetaan Banjir Rob Wilayah Medan Utara Menggunakan Regresi Logistik dan Gis

Abstract

Large cities in Indonesia, such as Jakarta, Surabaya, Semarang and Medan are vulnerable to tidal flooding, especially in the northern region which borders directly with sea waters. Hundreds of residents in the northern area of Medan experienced tidal flooding due to high tides that submerged their settlements. The need to map the tidal flood threat zone based on the factors causing tidal flooding in the North Medan area as a basis for relevant stakeholders in the context of handling to reduce losses due to tidal flooding Indicators of vulnerability to tidal flooding include data on rainfall, drainage density, land use, distance to the river, soil type, elevation, slope, aspect, distance to the estuary. Data analysis using Geographic Information System (GIS) and logistic regression. The research location is the sub-districts of Medan Belawan, Marelan and Labuhan. The results of the analysis obtained from the partial test are indicators of rainfall, drainage density, elevation, distance to the estuary, aspects that have a significant influence on tidal flood vulnerability. Meanwhile, indicators of land use, soil type, distance to the river, slope have no significant effect on tidal flood vulnerability. The results of the Odds Ratio value obtained that indicator ratings that affect tidal flood vulnerability from one to nine are distance to the estuary, elevation, distance to the river, soil type, aspect, land use, slope, rainfall and drainage density. The results based on the classification table with a total sample of 126 with 9 factors obtained as many as 6 environments that do not get vulnerability while 120 environments get vulnerability and the accuracy of the research model is 93.7%. Meanwhile, the results based on the classification table with a total sample of 209 with 9 factors obtained as many as 51 environments did not receive tidal flood vulnerability, while 158 neighborhoods received tidal flood vulnerability and the accuracy of the research model was 86.1%. While the sample of 126 with 2 factors obtained as many as 2 environments did not get vulnerability while 124 environments got vulnerability with 92.1% accuracy and sample 209 with 7 factors got 86.1% accuracy.

Kota besar di Indonesia, seperti Jakarta, Surabaya, Semarang dan Medan terancam terhadap banjir rob, khususnya di wilayah utara yang berbatasan langsung dengan perairan laut. Ratusan warga di kawasan utara Medan mengalami banjir rob akibat pasang air laut yang merendam permukiman mereka. Perlunya memetakan zona terancam banjir rob berdasarkan faktor-faktor penyebab banjir rob di wilayah Medan Utara sebagai dasar bagi pemangku kepentingan terkait dalam rangka penanganan untuk mengurangi kerugian akibat banjir rob. Indikator kerawanan terhadap banjir rob mencakup data curah hujan, drainage density, land use, jarak ke sungai, jenis tanah, elevasi, kemiringan, aspek, jarak ke muara. Analisis data menggunakan Geographic Information System (GIS) dan regresi logistik. Lokasi penelitian adalah kecamatan Medan Belawan, Marelan dan Labuhan. Hasil analisis yang didapat dari tes parsial yaitu indikator curah hujan, drainage density, elevasi, jarak ke muara, aspek mempunyai pengaruh signikan terhadap kerawanan banjir rob. Sedangkan indikator land use, jenis tanah, jarak ke sungai, kemiringan tidak mempunyai pengaruh signikan terhadap kerawanan banjir rob. Hasil nilai Odds Ratio didapat peringkat indikator yang mempengaruhi terhadap kerawanan banjir rob dari satu sampai sembilan adalah jarak ke muara, elevasi, jarak ke sungai, jenis tanah, aspek, land use, kemiringan, curah hujan dan drainage density. Hasil berdasarkan tabel klasifikasi dengan jumlah sampel 126 dengan 9 faktor didapat sebanyak 6 lingkungan yang tidak mendapat kerawanan sedangkan 120 lingkungan mendapat kerawanan serta ketepatan model penelitian sebesar 93,7%. Sementara, hasil berdasarkan tabel klasifikasi dengan jumlah sampel 209 dengan 9 faktor didapat sebanyak 51 lingkungan tidak mendapat kerawanan banjir rob, sedangkan 158 lingkungan mendapat kerawanan banjir rob serta ketepatan model penelitian sebesar 86,1%. Sedangkan sampel 126 dengan 2 faktor didapat sebanyak 2 lingkungan tidak mendapat kerawanan sedangkan 124 lingkungan mendapatkan kerawanan dengan ketepatan 92,1% dan sampel 209 dengan 7 faktor mendapat ketepatan 86,1%.