PENJEJAK KELUARAN AIRTANAH DI LEPAS PANTAI (KALP) DI PANTAI UTARA SEMARANG DAN SEKITARNYA DENGAN 222RADON

Abstract

Groundwater abstraction in Semarang City in the year of 2009 was 17,4 million-m3 per year and concentrated in North Semarang. That condition triggered a groundwater crisis indicated by a cone of depression of 20 meter depth within 30 m2 area. The water level decrease caused groundwater contamination in deep aquifer, sea water intrusion, land subsidence and rob. To detect sea water intrusion phenomena that related to submarine groundwater discharge (SGD), we conducted the investigation by radon isotope. The result showed a high radon level in sea water at some locations in this area that associated with sand alluvial deposit along the coast. It also indicated the presence of SGD in this area.