BRACKISH WATER MAPPING BASED ON WATER QUALITY DATA AND GEOELECTRICAL SURVEY : CASE STUDY IN THE SHALLOW GROUNDWATER OF TEGAL CITY

T R Puspita^[1],2*, D P E Putra¹, A H Rafsanjani¹, and R Farjrina ¹

¹ Department of Geological Engineering, Faculty of Engineering, Universitas Gadjah Mada

² Ministry of Public Work and Housing

[1]^* Corresponding author’s email: [email protected]

DOI: https://doi.org/10.20885/icsbe.vol2.art9 

ABSTRACT

Salty water in the aquifer influences changes in groundwater quality may cause by pumping activities and/or natural phenomena. This paper reported the result of salty water mapping in the shallow groundwater of Tegal city.  The EC values of groundwater in the study area ranges between 510 µS/cm to 7610 µS/cm, and TDS values are between 300 mg/L to 2450 mg/L. The geoelectrical measurement  on study area reveals a very low resistivity layer of 0.307 Ùm at a depth of 2.87 to 12 meters, indicating brackish water. Based on the EC and TDS also geoelectrical survey, a map of salty water is produced and shows that in shallow groundwater of Tegal City, brackish water appears in the middle part of City and northeast part near the coastal area.

Keywords : Water mapping; Water Quality Data; Geoelectrical

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