THE POLLUTION INDEX AND CARRYING CAPACITY OF THE UPSTREAM BRANTAS RIVER

River is one of the surface water resources that is often polluted by various human activities. With its dynamic characteristics, a river must be periodically examined to determine its water quality. This study aims to investigate the carrying capacity of the Brantas river in East Java, Indonesia. The observation was done by measuring TSS (Total suspended solid), TDS (Total dissolved solid), and oil and grease in the upstream zone of the Brantas river. This research used a descriptive method. The determination of the research stations was based on the condition of the watershed and its surroundings, assuming that there was a decrease in water quality. The sampling points include Pendem Bridge (1), DAM (local water company) Sengkaling (2), Simpang Remujung Bridge (3), and Samaan District (4). The results demonstrated that the upstream Brantas river at each sampling point had different pollution levels. Generally, the sampling point 1 (Pendem Bridge) was the cleanest zone compared to other sampling points. On the other hand, sampling point 4 (Samaan District) was the most polluted site of the upstream zone. Based on the quality standards of class III water (PP No. 82 Year 2001), it was noticeable that the upstream Brantas river was mildly polluted based on the TSS parameter. However, it was not polluted when referring to the TDS parameter and heavily polluted based on the oil and grease parameter. Regarding the carrying capacity, the upstream Brantas river at the sampling point 4 (Samaan District) has exceeded the capacity of the river for self-purification.