ANALISIS AREA LUAPAN BANJIR AKIBAT KENAIKAN DEBIT AIR BERBASIS SISTEM INFORMASI GEOGRAFIS (Studi Kasus : Das Banjir Kanal Timur Kota Semarang)

Mia Anggorowati Karomah, Arief Laila Nugraha, Arwan Putra Wijaya

Abstract


ABSTRAK

Kota Semarang merupakan salah satu wilayah di Indonesia yang rentan terhadap bencana banjir. Kondisi ini  di perparah dengan adanya penurunan tanah / land subsidence dan fenomena Rob (banjir pasang surut). Selain itu, adanya kenaikan debit air yang terjadi ketika musim penghujan, menyebabkan banjir di sepanjang muara Banjir Kanal Timur.

Penelitian ini menggunakan software ArcGIS versi 10 untuk mengetahui sebaran area luasan banjir dan HEC-RAS 4.1.0 untuk simulasi hidraulika. Teknik yang digunakan adalah memodelkan geometri sungai  dan membentuk model hidraulika berdasarkan data kontur dan penampang melintang sungai sehingga didapat sebaran area luapan banjir. Analisis unsteady flow digunakan untuk membuat peta debit rencana banjir 5,10, dan 25 tahun.

Dari hasil penelitian di dapat area luapan banjir terbesar yaitu Desa Terboyo Kulon Kecamatan Genuk, pada debit banjir rencana 5, 10, dan 25 tahun berturut turut sebesar 116,449 Ha, 117,520 Ha, dan 119,153 Ha. Tata guna lahan terdampak banjir terbesar adalah  tambak dengan luas berturut-turut 217,128 Ha, 218,851 Ha, dan 221,116 Ha. Hasil area luapan banjir disajikan dalam peta area luapan banjir dan peta area luapan banjir pada tata guna lahan debit banjir rencana 5, 10, dan 25 tahun.

Kata Kunci : SIG, HEC-RAS, Banjir Kanal Timur

 

ABSTRACT

Semarang is one of the areas in Indonesia that are prone to catastrophic flooding. This condition is getting worse with a decrease in land / land subsidence and the phenomenon of Rob(tide and gauge flood). In addition, an increase in water discharge that occurs during the rainy season, causing flooding along the Banjir Kanal Timur.

Study using ArcGIS software  version 10 to find out the distribution of flood area and HEC-RAS hydraulics simulation for hydraulics simulation.The technique used is to model the geometry of rivers and form a model based on the hydraulics contours and transverse cross section of the river that had spread in the flood overflow area. Analysis unsteady flow used for making maps of discharge flood plan 5, 10, and 25 years.

From the results of research in the area of the largest flood overflow is Kecamatan Genuk Terboyo Kulon Village, on flood discharge plan 5, 10, and 25 years of successive became one of 116,449 Ha, 117,520 Ha, and 119,153 Ha. Land use is the largest flood affected farm with an area of 217,128 Ha, respectively, 218,851 Ha, and 221,116 Ha. Results of the flood overflow areas presented in the overflow area flood maps and overflow area flood maps on land use of discharge flood plan 5, 10, and 25 years.

Keywords : GIS, HEC-RAS, Banjir Kanal Timur

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