The Mines and Geosciences Bureau (MGB) Region IV CALABARZON, in line with its long-standing mandate and function to conduct a regular specialized assessment program on evaluating the groundwater resources of the country, conducted a Groundwater Resource Assessment and Mapping study on three (3) pre-selected areas in the Province of Batangas:
- Municipality of Cuenca
- City of Tanauan
- City of Lipa
The study was conducted on May 20 to 26, 2019 and June 3 to 7, 2019 for the Municipality of Cuenca; June 21 to July 8, 2019 for the City of Tanauan; and August 13 to 30, 2019 for the City of Lipa. One of the purposes of the study was to assess the availability and vulnerability of the groundwater resources by recognizing the aquifer systems that contain these resources and its potentials and limitations. Another was to identify the different hydrogeological and formational units present in the study area. Lastly, it aimed to determine the groundwater occurrence, movement, discharge, and recharge, and analyze the existing groundwater issues and situation in the area of concern.
The groundwater resource assessment was spearheaded by the Hydrogeology and Environmental Geology Section of the Geosciences Division under MGB IV. It was supervised by Perlito A. Angeles, Supervising Geologist, and assisted by Geologists Alen Clyde A. Canlas and Kate Ashley A. Torrefranca.
A systematic collection of geologic, hydrologic, and meteorological information covering the three study areas was performed, which included different methodologies employed in the groundwater resource assessment including well inventory, water sampling, and geophysical survey. Global Positioning System (GPS) devices were used to determine the location of the wells while Hanna HI-9813-6 instrument was used to check the water quality parameters which are pH, EC, TDS and temperature upon water sampling. A geophysical survey was performed using IRIS Instruments Syscal R1 Plus and was processed using IPI2Win software.
The groundwater resource assessment and mapping conducted on the three areas show that the main source of groundwater in the area belongs to the thick and extensive confined aquifer on the underlying Taal Tuff considered under the Tuffaceous Sediments Aquifer System. Since groundwater was being utilized as the main source for municipal and city water use, the aquifer in which groundwater was contained was deemed highly productive and enough for the present-day situation.
Scattered around the three study areas were sites which included wide, open, and vegetated spaces as well as the elevated areas such as Mt. Maculot for Cuenca, Mt. Sungay for Tanauan City, and the Mt. Malepunyo for Lipa City. These sites were identified to be areas of groundwater recharge. Rainfall was determined to be the main contributor and source of groundwater recharge. Groundwater from the elevated areas of the three study areas generally move to lower elevations where it eventually drains to Laguna de Bay or Taal Lake through the drainage basins and streams identified in the study. Since portions of the three study areas are starting to be developed especially in Lipa City, recharge of the aquifer that the wells currently being utilized tap on can be affected due to a decrease in the amount of rainwater that percolates into the soil. However, no groundwater mining was observed for the present time.
It was concluded that the water districts, barangays, businesses, resorts, and private owners located on the three study areas, tap the groundwater through shallow and deep wells. At present, groundwater is enough to meet the demands of the populace. However, improvements on water distribution should be given attention to better facilitate the availability of potable water to the populace, and sustainability of groundwater extraction should be addressed through stricter measures on tapping of groundwater resources.
It was recommended that the construction of wells for future developments be regulated by the Local Government Units (LGU) to prevent possible over extraction of groundwater that could severely affect its availability. Continued reliance on extraction and use of groundwater is expected for the three study areas unless alternative sources are found which includes tapping of existing surface water through water bodies and rivers traversing the study areas.
A pitcher well being utilized by locals in Barangay Halang, City of Tanauan, Province of Batangas
An outcrop of Tuffaceous Sandstone observed in the road cut along Barangay Pantay Bata with coordinates 14°08’50.3” N and 121°06’22.3” E
Perlito A. Angeles, Supervising Geologist, along with Alen Clyde A. Canlas and Kate Ashley A. Torrefranca, Geologists, conducting a portion of georesistivity survey on Barangay San Felipe, Municipality of Cuenca, Province of Batangas
by: Alen Clyde A. Canlas | 3 October 2019