Understanding the quality and potential of groundwater for human purposes and peat fire disaster mitigation.

Issues related to groundwater sources in peat coastal areas are very complex. These include sea water intrusion and the quality of the groundwater itself. An additional issue is the source of water to extinguish peat fires. The study area of this research is located in the coastal zone of the Siak River delta, Indonesia. The coastal zone is covered mainly by peat soil, and it is vulnerable to fires in the peat during the dry season. This study investigates the potential of groundwater for preventing a peat fire disaster and for the possibility of domestic use in the community. Subsurface resistivity data were obtained by using 14 geoelectrical resistivity surveys with the Schlumberger configuration. Characteristics of the eight groundwater samples and 14 soil samples were analyzed. The resistivity of the peat soil ranges from 40 to 50 Ω-m, and the soil is distributed throughout the study area except the middle and east parts. Relative proportions of sand and gravel at various depths were observed through resistivity data. This zone is considered a potential aquifer. The water in the aquifer has a relatively high chloride content (63 to 1189 mg L⁻¹). The brackish water in the aquifer is believed to be ancient seawater trapped in the aquifer during the sedimentation process in the geologic past. However, the groundwater in the study area is more than enough to mitigate a peat fire disaster in the entire study area. [ABSTRACT FROM AUTHOR]