Spatio-temporal distribution of chlorine in the upper Tondano Watershed North Sulawesi Indonesia

Water resources are one of the natural resources that are vital both for the life of organisms on the earth as well as for daily human needs in various sectors of life. Due to limited resources, water management becomes essential. A study in the spatial-temporal of chlorine on the Tondano watershed is important because domestic agricultural waste has the potential to cause residues and affect water quality degradation. This study aims to examine the spatial and temporal distribution of chlorine in the upper Tondano watershed throughout seven years (2013-2019). Water sampling was carried out using the composite sampling method on the river and irrigation channel outlets. Chlorine concentration was measured by UV-VIS Spectrophotometry method, and other water quality parameters such as pH and temperature were measured in the field. The chlorine concentration fluctuated for each month during 2013 – 2019 (0.02 mg/L to 0.59 mg/L, Quality Standard PP 82/2001 chlorine 0.03 mg/L). The highest values were in March, September, and November. The trend showed that chlorine levels were above the quality standard in March and November. The high concentration of chlorine in the Panasen River water bodies is partly due to the application of KCI fertilizers and, pesticides in rice fields and horticultural lands, as well as domestic waste.