Oral Presentation NCGRT/IAH Australasian Groundwater Conference 2019

Hydrogeological characterisation of volcanic-sedimentary rock aquifer within Southern Johor Bahru, Malaysia (344)

Vynotdni Rathinasamy 1 , Edy Tonnizam Mohamd 1 , Muhammad Nassir Hanapi 1 , Rosli Saad 2 , Ibarhim Komoo 3
  1. Universiti Teknologi Malaysia, Skudai, Johor, Malaysia
  2. Universiti Sains Malaysia, Pulau Pinang, Malaysia
  3. Universit Kebangsaan Malaysia, Bangi, Malaysia

The properties of volcanic-sedimentary rock aquifers are definitely forthright and the results are volatile due to its spatial heterogeneity, especially in the tropical region where higher degree of weathering is a norm. A study on hydrogeological characteristics of volcanic-sedimentary rock aquifer in Southern Johor Bahru was carried out. This region is underlain by Jurong Formation in which the upper member is made up of interbedded sandstone and clay while lower member is made up of primarily tuff. First, the 2D resistivity survey was carried out to identify potential aquifer zone. Upon identifying possible fractured zone, drilling was carried out at one location followed by pumping test. The groundwater samples were collected for quality testing. The preliminary result shows that the depth of fractured rock aquifer was 120-170 m and the resistivity was 70-600 Ohm.m. The air-lift yield indicated that the yield increased from 7.57 m3/hr at first predicted fractured/jointed (at 136m) to 38 m3/hr at second predicted fractured zone (at 165m). In addition, pumping test shows that the aquifer acts as double-porosity model. The aquifer characteristics obtained were 7.85 m2/d for transmissivity, 1.05x10-1 m/d for hydraulic conductivity and 5.26 x 10-1 for storativity. The quality test indicated that the pH and total dissolved solids of groundwater is 7.6-7.8 and 170-180 mg/L respectively. Hence, the preliminary results imply that identifying major fracture system in this region is vital for exploration it controls the quantity of groundwater. Also, the quality of the groundwater was good when compared with international standards.