PENILAIAN DAYA TAMPUNG BEBAN PENCEMARAN SUNGAI DI SUB-DAS SERAYU KABUPATEN WONOSOBO MENGGUNAKAN QUAL2KW

ZAHWA USWATUL HIKMAH, Dr. M. Widyastuti, M.T.

2025 | Skripsi | GEOGRAFI DAN ILMU LINGKUNGAN

Sungai Serayu memiliki peran penting dalam mendukung kegiatan domestik, pertanian, dan peternakan di Kabupaten Wonosobo. Namun, aktivitas penggunaan lahan yang intensif berpotensi menghasilkan beban pencemar dari sumber non titik (non-point source), yang dapat menurunkan kualitas air sungai dan melebihi daya tampung alami sungai. Oleh karena itu, diperlukan pendekatan kuantitatif untuk mengevaluasi kondisi kualitas air dan menghitung daya tampung beban pencemar (DTBP) berdasarkan parameter utama.

Penelitian ini bertujuan untuk menilai kualitas air Sungai Serayu menggunakan perangkat lunak QUAL2KW, berdasarkan data observasi lapangan di tujuh titik pengamatan. Parameter yang dikaji meliputi Biochemichal Oxygen Demand (BOD), Chemichal Oxygen Demand (COD), dan Total Suspended Solid (TSS). Pemodelan dilakukan melalui tahap kalibrasi dan validasi untuk memperoleh kesesuaian antara data observasi dan simulasi model, diikuti analisis spasial terhadap beban pencemar aktual, kontribusi sektoral, dan perhitungan daya tampung berdasarkan debit sungai 1 m³/ detik dan baku mutu kelas II (PP No. 22 Tahun 2021).

Hasil penelitian menunjukkan bahwa sumber pencemar non titik di Sungai Serayu berasal dari sektor domestik, pertanian, dan peternakan. Beban pencemar organik (BOD dan COD) paling dominan berasal dari sektor domestik di segmen hulu, sementara padatan tersuspensi (TSS) didominasi aktivitas pertanian di segmen hilir. Total beban pencemar tertinggi ditemukan pada segmen 6 untuk COD (0,0702 ton/jam) dan TSS (0,936 ton/jam), serta pada segmen 1 untuk BOD (0,0166 ton/jam). Daya tampung maksimum masing-masing parameter adalah 0,0634 ton/jam (BOD), 0,3501 ton/jam (COD), dan 1,710 ton/jam (TSS), dengan variasi kapasitas antar segmen dipengaruhi oleh morfologi sungai. Secara spasial, seluruh segmen masih berada dalam batas daya tampung untuk COD, sedangkan hanya segmen 1 melebihi daya tampung untuk BOD, serta segmen 5 dan 6 melebihi untuk TSS. Dengan demikian, pengendalian lokal perlu dilakukan untuk menjaga fungsi ekologi Sungai Serayu secara berkelanjutan.

The Serayu River plays a significant role in supporting domestic, agricultural, and livestock activities in Wonosobo Regency. However, intensive land use has the potential to introduce non-point source pollutants that degrade water quality and may exceed the river’s pollutant carrying capacity. A quantitative approach is thus required to assess current water quality and estimate total maximum daily loads (TMDL) for key parameters.

This study aims to model the water quality of the Serayu River using QUAL2KW, based on observations from seven monitoring stations. The main parameters analyzed include BOD, COD, and TSS. The modeling involved calibration and validation to match field data, followed by spatial analysis of pollutant loads, sectoral contributions from non-point sources, and load capacity estimation under an assumed flow rate of 1 m³/s, based on Class II water standards (PP No. 22 of 2021).

The results indicate that non-point source pollution in the Serayu River originates from three primary sectors: domestic, agriculture, and livestock. Organic pollutants (BOD and COD) were predominantly contributed by domestic activities in the upstream segments, while suspended solids (TSS) were mainly derived from agricultural activities in the downstream segments. The highest pollutant loads were observed in Segment 6 for COD (0.0702 tons/hour) and TSS (0.936 tons/hour), and in Segment 1 for BOD (0.0166 tons/hour). The maximum carrying capacities for each parameter were 0.0634 tons/hour (BOD), 0.3501 tons/hour (COD), and 1.710 tons/hour (TSS), with variations across segments influenced by river morphology. Spatially, all segments remained within the carrying capacity for COD, while Segment 1 exceeded the limit for BOD, and Segments 5 and 6 exceeded the threshold for TSS. Therefore, localized pollutant control measures are necessary to sustain the ecological functions of the Serayu River.

Kata Kunci : Daya tampung beban pencemaran, Sungai Serayu, QUAL2KW, Kualitas air, Sumber pencemar non titik