Electronic Theses and Dissertation

Sungai Krueng Peusangan memiliki peran penting bagi pemenuhan kebutuhan air dan aktivitas masyarakat di sekitarnya, namun peningkatan aktivitas antropogenik di sepanjang daerah aliran sungai berpotensi menurunkan kualitas air. Penelitian ini bertujuan untuk menentukan status mutu air Sungai Krueng Peusangan menggunakan metode Indeks Pencemaran (IP) serta menganalisis dinamika kualitas air secara spasial dan temporal melalui pemodelan QUAL2KW. Pengambilan sampel dilakukan pada enam titik pengamatan yang mewakili kondisi hulu hingga hilir pada musim kemarau dan musim hujan tahun 2025. Parameter kualitas air dianalisis berdasarkan baku mutu air Kelas II sesuai Peraturan Pemerintah Republik Indonesia Nomor 22 Tahun 2021.
Hasil pengujian kualitas air menunjukkan bahwa sebagian besar parameter masih memenuhi baku mutu, meskipun pada beberapa lokasi dan waktu tertentu terjadi peningkatan konsentrasi TSS, BOD, COD, serta fecal coliform. Hasil perhitungan Indeks Pencemaran menunjukkan bahwa seluruh titik pengamatan berada pada kategori tercemar ringan dengan nilai IP berkisar antara 1,176–1,496 dan nilai rata-rata sebesar 1,316. Nilai IP pada musim hujan lebih tinggi dibandingkan musim kemarau, yang mengindikasikan pengaruh limpasan permukaan terhadap peningkatan beban pencemar di badan sungai.
Hasil simulasi kualitas air menggunakan model QUAL2KW menunjukkan adanya penurunan konsentrasi oksigen terlarut (DO) serta peningkatan konsentrasi BOD dan nutrien pada beberapa segmen sungai, terutama di bagian tengah hingga hilir. Kondisi ini mencerminkan bahwa kemampuan pemurnian alami sungai belum sepenuhnya mampu mengimbangi masukan beban pencemar akibat aktivitas antropogenik yang berlangsung secara berkelanjutan. Integrasi metode IP dan pemodelan QUAL2KW memberikan gambaran yang lebih komprehensif mengenai kondisi dan dinamika kualitas air Sungai Krueng Peusangan serta dapat dijadikan dasar dalam perumusan strategi pengelolaan dan pengendalian pencemaran sungai secara berkelanjutan.
Kata Kunci: Indeks Pencemaran, pemodelan QUAL2KW, kualitas air sungai, pencemaran, Sungai Krueng Peusangan

The Krueng Peusangan River plays an important role in meeting the water needs and activities of the surrounding community, but increased anthropogenic activity along the river basin has the potential to reduce water quality. This study aims to determine the water quality status of the Krueng Peusangan River using the Pollution Index (PI) method and to analyze the spatial and temporal dynamics of water quality through QUAL2KW modeling. Samples were collected at six observation points representing conditions from upstream to downstream during the dry and rainy seasons of 2025. Water quality parameters were analyzed based on Class II water quality standards in accordance with Government Regulation of the Republic of Indonesia Number 22 of 2021. Water quality test results show that most parameters still meet quality standards, although at certain locations and times there has been an increase in the concentration of TSS, BOD, COD, and fecal coliform. The Pollution Index calculation results show that all observation points are in the lightly polluted category with PI values ranging from 1.176 to 1.496 and an average value of 1.316. The PI value in the rainy season is higher than in the dry season, indicating the effect of surface runoff on the increase in pollutant load in the river. The results of water quality simulations using the QUAL2KW model show a decrease in dissolved oxygen (DO) concentrations and an increase in BOD and nutrient concentrations in several segments of the river, especially in the middle to downstream sections. These conditions reflect that the river's natural purification capacity is not yet fully able to offset the pollutant load input from ongoing anthropogenic activities. The integration of the IP method and QUAL2KW modeling provides a more comprehensive picture of the condition and dynamics of water quality in the Krueng Peusangan River and can be used as a basis for formulating strategies for sustainable river pollution management and control. Keyword: Pollution Index, QUAL2KW modeling, river water quality, pollution, Krueng Peusangan River