Efektivitas Tanggul Dalam Mengurangi Banjir di Kawasan Perkebunan Kelapa Sawit PT REA GROUP, Kalimantan Timur

Abstract

Banjir di kawasan perkebunan kelapa sawit di Kalimantan Timur, khususnya di Sungai Belayan, mengancam keberlanjutan produksi dan infrastruktur. Sungai Belayan, anak Sungai Mahakam, sering mengalami peningkatan debit air yang menyebabkan banjir, terutama saat musim hujan. Perkebunan kelapa sawit yang terletak di daerah rawan banjir memerlukan solusi mitigasi efektif, salah satunya pembangunan tanggul. Pemodelan HEC-RAS 2D menunjukkan bahwa tanggul di sepanjang sungai utama efektif mengurangi luas dan kedalaman genangan banjir. Tanggul yang dibangun di wilayah Tepian dan Sentekan mengurangi genangan dari 887,09 hektar menjadi 200,03 hektar dan dari 244,07 hektar menjadi 53,83 hektar di Cakra. Analisis topografi dan elevasi menggunakan fitur Terrain Modification membantu menentukan lokasi optimal, dengan tanggul lebih panjang dibutuhkan di dataran rendah seperti Damai dan Lestari, serta lebih pendek di wilayah tinggi seperti Perdana. Hasil pemodelan juga menunjukkan bahwa kedalaman genangan banjir di sebagian besar wilayah kini berada pada 0–0,5 meter, yang tidak membahayakan perkebunan kelapa sawit, menegaskan efektivitas tanggul dalam mengurangi baik luas maupun kedalaman genangan banjir.

Flooding in the oil palm plantation regions of East Kalimantan, particularly along the Belayan River, poses a significant threat to the sustainability of production and infrastructure. The Belayan River, a tributary of the Mahakam River, frequently experiences increased water flow, resulting in flooding, particularly during the rainy season. Oil palm plantations situated in flood-prone areas necessitate effective mitigation strategies, one of which is the construction of levees. HEC-RAS 2D modeling indicates that levees along the main river effectively diminish both the area and depth of flood inundation. Specifically, levees constructed in the Tepian and Sentekan areas reduced flooding from 887.09 to 200.03 ha and from 244.07 to 53.83 ha in Cakra. Topographic and elevation analyses utilizing Terrain Modification features assist in determining optimal locations, with longer levees required in lowland areas such as Damai and Lestari, and shorter ones in higher areas such as Perdana. The modeling results further demonstrate that flood depths in most areas are now between 0-0.5 meters, which does not pose a threat to the oil palm plantations, thereby confirming the effectiveness of the levees in reducing both the area and depth of flood inundation.