Phosphorus load concentration in tropical climates reservoir for each water quantity class

Saguling Reservoir has a potential to be used as a raw water supply for Bandung Metropolitan Area (BMA), with the discharge of 1.622 dm·s−1. However, further studies are needed to ensure that the water quality is in accordance with the government regulations. This study shows that the reservoir’s P concentration was 315.0 mg·m−3 on average in 1999–2013. This value only meets the class III of government standards of water quality for the cultivation of freshwater fish, livestock, and to irrigate landscaping, but does not belong to the class I standard of 200 mg·m−3 for drinking water. The total-P concentration in wet, normal, and dry years was 796.3, 643.8, and 674.8 mg·m−3, respectively. The pollution load was highest in wet years due to the high levels of sediment. The pollution load of the reservoir did not exceed the class III classification of 29 405.01 kg·year−1. The pollution load in wet, normal, and dry years was 38 790.1, 25 991.9, and 23 929.0 kg·year−1, respectively. The phosphorus pollution is caused by the use of floating net cages in the reservoir, which makes it difficult to meet the standards. In wet years, the pollution load was higher than in normal and dry years. The P load could be higher in the wet season due to dilution and could probably decrease the pollutant concentration in the reservoir.