The Used of Storet Index to Assess Water Quality in Perancak Estuary, Bali, Indonesia

Water quality in the environment is influenced by anthropogenic activity and natural process. Anthropogenic activities such as fishing activities, fish ponds, fishing ports, residential waste provide the greatest contribution to water quality conditions. The condition of water quality is very important in supporting the survival of the organisms living on it. Determination of the status of water quality should be done as a reference for pollution monitoring in an aquatic system for both marine tourism development and biota life purposes, especially in the mangrove ecosystem. This study aims to assess the status of water quality in Perancak Estuary Jembrana Bali for marine tourism and the mangrove ecosystem. Water quality measurement was conducted from January to March 2018 at 10 observation stations which divided into 3 zones based on the representation of area characteristics. These zones include: zone I represent water quality conditions close to residential areas, zone II represent water quality conditions close to mangrove and aquaculture ecosystems, and zone III represent sea water quality transition conditions. The sampling procedure was based on APHA standard method. The water quality data then analysed using the STORET method. Stored index for marine tourism and marine biota (mangrove) in zone I, II, III showed lightly contaminated to moderately polluted (-10 until -16) for physical parameters, heavily polluted (-40 until -80) for chemical parameter and biology parameters is still in accordance with quality standards until lightly contaminated (0 until -6). Based on the value of the pollution index shows the water quality status of Perancak Estuary from January-March is classified as bad/severe pollution both for marine tourism and the mangrove ecosystem. Chemical parameters (nitrate, phosphate, ammonia) contribute the most to the level of pollution.