Parameter estimation and vulnerability assessment of coastal unconfined aquifer to saltwater intrusion

A. Mahesha, Vyshali, U. A. Lathashri, H. Ramesh

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The focus of the present work is to characterize a tropical, coastal aquifer and to carry out its vulnerability to saltwater intrusion using hydrogeological parameters. The characterization of the aquifer involves pumping tests, vertical electrical sounding, and water quality analysis carried out at 41 monitoring wells. The area under investigation lies between two tropical, seasonal, tidal rivers, i.e., Pavanje and Gurpur rivers, joining the Arabian on the west coast of India. The aquifer is predominantly shallow and unconfined, having moderate to good groundwater potential with transimissivity and specific yield ranging from 49.2 to 461:4 m2/day and 0.00058 to 0.2805, respectively. The electrical resistivity tests indicated that the thickness of the aquifer ranges from 18 to 30 m. The study also investigates the saltwater affected areas in the region the vertical electrical sounding and water quality analysis. The resistivity results revealed several probable isolated saltwater intruded pockets in the region with resistivity less than 70 Om. From the salinity analysis of water, the locations that are affected during February to May (summer) and throughout the year are identified. The wells that are located close to the coast (< 350 m) and at lower elevations (well bottom < +1 m) were found to be saline throughout the year. Also, wells along the banks of the river show considerable salinity (> 200 ppm) during the summer period from tidal inflow along the rivers. The water samples were also analyzed for chloride to bicarbonate ratios during December to May at all the monitoring wells and were found to be exceeding the allowable limit at several locations. The saltwater vulnerability maps are derived for the area by the index-based method using the hydrogeological parameters. The method was found to be effective while compared to the field observations. The results from the analysis indicate that the aquifer is medium to highly vulnerable to saltwater intrusion at majority of the locations. The impact of projected sea level rise by 0.25 and 0.50 m from the climate change is also assessed on the vulnerability of the region to saltwater intrusion.

Original languageEnglish
Pages (from-to)933-943
Number of pages11
JournalJournal of Hydrologic Engineering
Volume17
Issue number8
DOIs
Publication statusPublished - 01-12-2012
Externally publishedYes

Fingerprint

saline intrusion
coastal aquifer
unconfined aquifer
Aquifers
Parameter estimation
vulnerability
aquifer
vertical electrical sounding
electrical resistivity
well
Rivers
river
Water quality
Coastal zones
water quality
coast
summer
monitoring
bicarbonate
Water

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Civil and Structural Engineering
  • Water Science and Technology
  • Environmental Science(all)

Cite this

Mahesha, A. ; Vyshali ; Lathashri, U. A. ; Ramesh, H. / Parameter estimation and vulnerability assessment of coastal unconfined aquifer to saltwater intrusion. In: Journal of Hydrologic Engineering. 2012 ; Vol. 17, No. 8. pp. 933-943.
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Parameter estimation and vulnerability assessment of coastal unconfined aquifer to saltwater intrusion. / Mahesha, A.; Vyshali; Lathashri, U. A.; Ramesh, H.

In: Journal of Hydrologic Engineering, Vol. 17, No. 8, 01.12.2012, p. 933-943.

Research output: Contribution to journalArticle

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