Spatial and temporal description of water pollution status of Gajah Mungkur Reservoir Wonogiri, Central Java, Indonesia

WIRYANTO WIRYANTO

Biodiversitas Journal of Biological Diversity
Vol. 17 No. 2 (2016)

Abstract. Wiryanto. 2016. Spatial and temporal description of water pollution status of Gajah Mungkur Reservoir Wonogiri, Central Java, Indonesia. Biodiversitas 17: 888-893.  Gajah Mungkur Reservoir (GMR) Wonogiri, Central Java, Indonesia was established with the purpose of: to control downstream flood, as hydropower generation, as fish farming, as a tourism destination and as an irrigation system in the dry season. As tourism destination and aquaculture, based on PPRI No. 82 2001, this reservoir is included in the category of class 2. The main purpose of this study was to determine the status of water pollution and activities of pollutant contributor to Gajah Mungkur Reservoir (GMR) Wonogiri spatially and temporally, in accordance with its purpose as the tourist destination and fish farming. Survey method study, purposive sampling method. The sampling was conducted at 8 stations (estuaries of Wuryantoro Sub- Drainage Basin (SubDAS), Alang-Solo Hulu Sub-Drainage Basin, Temon Sub-Drainage Basin, Keduang Sub-Drainage Basin, Tourism area, Fish culture area and aquaculture free zone, as well as the spillway or outlet), 4 times (in March, June, September and December) in the year 2011. The result shows that some reservoir water pollution parameters such as TSS, BOD5, COD, Cu, Mn and Escherichia coli have been above the boundary required as class 2 water category based on PPRI No. 82 of 2001. Based on Storet calculations model, GMR Wonogiri waters are spatially distributed as heavily polluted on estuaries of Temon Sub-Drainage Basin and Keduang Sub-Drainage Basin, as moderately polluted on other 6 stations and temporally, on samplings on March 2011, GMR is heavily polluted, and the others are moderately polluted. Based on the calculation of Pollution Index spatial distribution, station 4 (Keduang estuary) is moderately polluted, and the other stations are lightly polluted, but based on the temporal distribution, the pollution status of GMR is lightly polluted. Pollutants flowing into GMR are dominated by wastes produced by households and industry activities from outside the reservoir (on the rainy season) and from KJA and tourism activities.