On Defining the Effects of Water Temperatures Increase to the Coral Reef: A Case Study of Cooling Water Discharge from a Power Generation

Coral reef is one of the coastal marine ecosystems which highly productive, biodiverse, and economically valuable. However they are also fragile, sensitive and easily stressed by environmental change, including impacts from seawater temperature increases from the disposal of the cooling water from power generationsat the coastal environement. This paper presents results from an ongoing study on effects of elevated water temperatures on coral reefs ecosystem, associated with a cooling water discharge from an operating power generation. Thermal dispersion modeling was undertaken and a model verification was conducted for both hydrodynamics components, i.e. tides and currents. Environmental monitoring was conducted in the coastal waters around the power plant, located at Paiton subdistrict, Probolinggo, East Java, Indonesia, from 2008-2013. Comparisons showed a good agreement between the modeling and the monitoring data. Four stations were defined based on the hydrodynamics modeling to indicate which stations that are influenced and not influenced by the cooling water. Seawater quality data has been gathered, including key environmental indicators, i.e., temperature,salinity, water clarityandtotal dissolved solids(TDS). The Line Intercept Transect (LIT) method was used to assess the reefs ecosystem. The results indicate that increasing in the natural water temperature of Paitonarea are affectinglifeform composition and growthof corals. This informationis useful for improving the development of cooling water quality standards.