Water Quality Modeling Distribution at Bali Strait in the Western Monsoon and Its Impact for Ecosystems

The Bali Strait is geographically located between Java and Bali Island, with a total area approximately 900 square miles. It has a high potential of fish produces an average of 100 tons/year. The types of fishes there are tongkol, layang, and lemuru with high economic values. Bali Strait affected by the oceanographic phenomenon of upwelling in the Indian Ocean and has shallow and narrow bathymetry conditions made high currents speeds. The abundance of nutrients in Bali Straits made the ocean water fertile and rich in fish give an advantage for anglers. The nutrient is present in Bali Strait caused by water flow from land. These conditions is become triggers for an explosion of phytoplankton populations or called booming algae. The shrimp waste from companies disposing of the waste to Bali Strait consists of parameter DO, BOD, COD, TSS, Phosphate, and Nitrate. Research on the distribution of water quality in Bali Strait in the Western Monsoon has to research, where previous researchers have researched in the Eastern Monsoon. The purpose of this research is to find out the distribution of water quality parameters in the Bali Strait using MIKE 21 Ecolab [1]. The result of this research shown the maximum distribution exceed water quality parameter and influence for the biota are BOD = 83.031 mg/L, Nitrate = 0.924 mg/L, Phosphate = 0.176 mg/L and TSS = 27.574 mg/L. The BOD makes the water polluted, Nitrate and Phosphate is the trigger for booming algae, and TSS is not suitable for coral and sea grass.