GROUNDWATER FLOW AND VARIATION IN GROUNDWATER QUALITY AT A LANDFILL SITE LOCATED IN HILLY TERRAIN

Abstract

 We have noticed a variation in the quality of groundwater produced from monitoring wells at a site located in a hilly terrain where both controlled-type landfill and inert waste landfill were placed. In order to clarify the mechanisms of groundwater quality development at the site, we conducted a monthly water quality monitoring in 2018, and analyzed the temporal and spatial variation of the data, as well as correlation between water quality indices. A groundwater flow simulation using MODFLOW6 for a 17 year-period, from the completion of the controlled landfill to the present time, was also conducted. Water quality analysis showed that for some groundwater samples, both natural and artificial processes could have affected their water quality. Numerical simulation suggested the possibility groundwater collection pipe placed around controlled landfill have collected seepage water from one of the inert waste landfills. The results suggest that all the facilities located within a hydrogeological boundaries of the site have to be considered when considering the effect of groundwater drainage system on the quality and amount of groundwater