Dinamika Spasio-Temporal Kualitas Air dan Kaitannya dengan Perubahan Tutupan Lahan dan Kepadatan Penduduk pada DAS Angke-Pesanggrahan

Abstract

DAS Angke-Pesanggrahan merupakan DAS yang menghadapi tekanan antropogenik akibat urbanisasi, perubahan tutupan lahan, dan peningkatan kepadatan penduduk. Hal ini menyebabkan peningkatan beban pencemar dan penurunan kualitas air sungai secara spasial dan temporal. Penelitian ini bertujuan untuk menganalisis dinamika spasio-temporal kualitas air di DAS Angke-Pesanggrahan serta mengidentifikasi hubungannya dengan perubahan tutupan lahan dan kepadatan penduduk. Penelitian ini dilakukan pada November-Mei melalui pengumpulan data kualitas air di 28 titik pengamatan pada tahun 2016, 2019, dan 2024. Parameter yang dianalisis meliputi TDS, TSS, pH, BOD, COD, DO, minyak dan lemak, MBAS, Total-P, NO2, NO3, dan NH3. Analisis spasial dilakukan menggunakan Surfer 16 dan ArcMap 10.8. Keterkaitan antara parameter kualitas air, perubahan tutupan lahan, dan kepadatan penduduk dianalisis menggunakan PCA dan korelasi Pearson. Hasil penelitian menunjukkan kualitas air terburuk secara konsisten ditemukan di zona hilir yang memiliki kepadatan penduduk dan proporsi lahan terbangun tertinggi. Secara temporal, kualitas air menunjukkan kecenderungan memburuk selama periode 2016–2024 dengan beberapa parameter utama, yaitu BOD, COD, Total-P, DO, MBAS, NO2, dan NH3. Hasil menunjukkan degradasi kualitas air yang signifikan, terutama pada tahun 2024, ditandai penurunan DO menjadi 2,29 mg/L (40,97%) dan lonjakan amonia hingga 5,61 mg/L. Lahan terbangun berkorelasi positif sangat kuat dengan amonia dan nitrit, sedangkan tutupan hutan berkorelasi positif sangat kuat dengan DO (r = 1,00). Pengendalian perubahan tutupan lahan dan pencemaran secara terpadu diperlukan untuk mendukung pengelolaan DAS yang berkelanjutan.

The Angke–Pesanggrahan Watershed has been subjected to increasing anthropogenic pressure driven by urbanization, land use/land cover (LULC) change, and population growth. These factors have contributed to increasing pollutant loads and the deterioration of river water quality across both spatial and temporal scales. This study aimed to analyze the spatiotemporal dynamics of water quality in the Angke–Pesanggrahan Watershed and examine its relationship with LULC change and population density. The study was conducted from November to May using water quality data collected from 28 monitoring stations in 2016, 2019, and 2024. The analyzed parameters included TDS, TSS, pH, BOD, COD, DO, oil and grease, MBAS, Total-P, NO2, NO3, and NH3. Spatial analysis was performed using Surfer 16 and ArcMap 10.8. The relationships among water quality parameters, LULC change, and population density were analyzed using principal component analysis (PCA) and Pearson correlation analysis. The results showed that the poorest water quality consistently occurred in the downstream zone, where population density and the proportion of built-up land were the highest. Temporally, water quality exhibited a declining trend from 2016 to 2024, particularly for BOD, COD, Total-P, DO, MBAS, NO2, and NH3. Water quality degradation became more pronounced in 2024, as indicated by a decrease in DO to 2.29 mg/L (40.97%) and an increase in NH3 concentration to 5.61 mg/L. Built-up land showed a very strong positive correlation with NH3 and NO2, whereas forest cover exhibited a very strong positive correlation with DO (r = 1.00). Integrated management of LULC change and pollution control is therefore essential to support sustainable watershed management.