Transport Modelling In Jakarta Groundwater Basin using QSWATMOD

Abstract

The Jakarta groundwater basin is constructed by tertiary, Pleistocene and resent rock consisting of sedimentary rocks, volcanic activities and alluvial. There are three very potential aquifer layers found in this basin i.e. shallow aquifers, upper confined aquifers, and lower confined aquifers bounded by several aquitard. High economic and development activities cause high vulnerability to polluted aquifers such as nutrients. Previous research mentioned the presence of nutrients in groundwater in urban areas can be caused by high anthropogenic activity. Nutrient contamination in groundwater can be a threat to ecosystems in coastal areas. The purpose of this paper is to understand nutrient transport patterns through groundwater hydrogeology systems in the Jakarta groundwater basin, so that the amount of groundwater contribution to the nutrient flux in the Jakarta bay can be estimated. To get the transport nutrient model, QSWATMOD tools in QGIS Software were used. The parameters used in transport nutrient modeling are the definition of subbasins in the SWAT hydrology model, Hydrological Response Unit (HRU), rivers, aquifer thickness, hydraulic conductivity, specific storage, specific yield, hydraulic head, porosity, longitudinal dispersivity, and denitrification rate constant. The sub-basins and river constraints used are the Ciliwung Watersheds fill the Jakarta groundwater basin. The result show Leached Nitrate at the study area was 42 kg/ha and total P loss were 5 kg/ha. However the higher groundwater recharge in the study area increased the risk of groundwater contaminant by nitrate.