Sulfiati, Dewi Ayu Setiawaty, Yulfin Tanduk Allo Biyang

STUDI NORMALISASI SUNGAI PADA SUNGAI PALU

Introduction

Studi normalisasi sungai pada sungai palu . Normalisasi Sungai Palu, Sulawesi Tengah, dianalisis untuk atasi banjir dan sedimentasi. Studi intensitas curah hujan & debit banjir menunjukkan saluran eksisting mampu menampung debit 100 tahun.

Abstract

Sungai Palu merupakan salah satu sungai di Kota Palu, Provinsi Sulawesi Tengah,  yang juga mengalami berbagai permasalahan seperti banjir, sedimentasi yang tinggi dan degradasi kualitas air yang mempengaruhi lingkungan sekitar. Salah satu upaya untuk mengatasi permasalahan tersebut adalah dengan melakukan normalisasi sungai. Penelitian ini bertujuan untuk mengetahui berapa besar intensitas curah hujan pada Sungai Palu dan berapa besar debit banjir Sungai Palu. Data yang digunakan adalah data sekunder berupa curah hujan harian selama 10 tahun dan data dimensi penampang melintang Sungai Palu. Hasil hitungan hujan rencana kala ulang 100 tahun dengan metode Log Pearson Tipe III yaitu 12,176 mm, dan dari hasil hitungan intensitas hujan terlihat bahwa bahwa hujan deras pada berlangsung dalam jangka waktu singkat, namun hujan tidak deras berlangsung dalam waktu lama. Debit banjir rencana kala ulang 100 tahun dengan menggunakan metode Hidrograf Satuan Sintetik Nakayasu yakni 664,448 m3/det. Langkah selanjutnya menggunakan aplikasi HEC-RAS 6.6 untuk mengetahui kapasitas penampang saluran drainase dengan menggunakan debit rencana. Dari hasil analisis aplikasi HEC-RAS, kondisi eksisting Sungai Palu khususnya pada area yang ditinjau yakni di Kelurahan Baru, Kecamatan Palu Barat, dengan debit kala ulang 100 tahun mampu menampung debit yang ada sehingga tidak perlu mendesain ulang saluran.

Review

This study, titled "STUDI NORMALISASI SUNGAI PADA SUNGAI PALU," addresses pressing environmental challenges faced by the Palu River in Central Sulawesi, including recurrent flooding, high sedimentation, and degrading water quality. The research primarily aimed to establish critical hydrological parameters necessary for potential river normalization efforts, specifically focusing on quantifying rainfall intensity and determining flood discharge magnitudes. Utilizing secondary data consisting of ten years of daily rainfall records and existing river cross-sectional dimensions, the study sets out to provide foundational data for subsequent mitigation strategies. The methodology employed robust hydrological engineering techniques. The 100-year return period rainfall was calculated to be 12.176 mm using the Log Pearson Type III method, with observations indicating that heavy rainfall events are typically short-lived, while lighter rainfall persists for longer durations. Subsequently, the 100-year return period flood discharge was estimated at a substantial 664.448 m³/sec, derived through the Nakayasu Synthetic Unit Hydrograph method. A crucial final step involved leveraging the HEC-RAS 6.6 software to evaluate the hydraulic capacity of the existing river channel against this calculated design flood. The analysis yielded a significant finding: the Sungai Palu, specifically within the investigated area of Kelurahan Baru in Palu Barat District, possesses adequate capacity to accommodate the 100-year flood discharge, suggesting that immediate redesign of the channel in this section is not required. The finding that the existing channel capacity in the analyzed section is sufficient for a 100-year flood is a valuable insight, potentially guiding local flood management and investment decisions. However, while the study's title implies a comprehensive "normalisasi sungai" (river normalization) that typically encompasses broader environmental improvements beyond flood control, the abstract predominantly focuses on flood capacity. The initial problems identified, such as high sedimentation and water quality degradation, are not explicitly addressed in the presented findings or subsequent recommendations. For a more holistic understanding and effective normalization plan, future research should consider expanding the scope to cover the entire river length and integrate detailed investigations into sediment transport dynamics, erosion patterns, and water quality parameters, thereby fully addressing the multifaceted challenges initially highlighted.

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