Discharge, Sediment, and Dissolved Nutrients in a Conservation Forest of the Cigumentong Catchment, Citarum Watershed, Tropical Monsoon Region, Indonesia

The Cigumentong catchment is a conservation forest area that experiences erosion, sedimentation, river flow pollution, and flooding. Research is needed to identify parameters that can gauge the effectiveness of conservation forests, informing policies aimed at preserving their sustainability. The methods used in this study include observing water level height with an AWLR (Automatic Water Level Recorder), measuring rainfall with an ARR (Automatic Rain Recorder), and conducting water sampling using an automatic water sampler, followed by nutrient analysis in the laboratory. The results show that the peak flow discharge occurred 50 minutes after the peak rainfall, on average. Peak sediment and nutrient concentrations occurred after the peak flow discharge with average intervals of 30 minutes for sediment, 155 minutes for total nitrogen, 30 minutes for total phosphorus, and 35 minutes for total potassium. The observation of sediment and nutrient discharge produced a counterclockwise hysteresis pattern. The peak of sediment and nutrient discharge occurring after the peak flow discharge can be one criterion indicating that the hydrological conditions in the Cigumentong catchment are still healthy. This study contributes hydrological information as a reference for maximizing the conservation function.