Influence of Saltwater Submergence on Geohydraulic Properties of Sand: A Laboratory Investigation

Sudip Basack,Moses Karakouzian,Sumanpran Sonowal,Ghritartha Goswami

doi:10.3390/hydrology8040181

Abstract

Saline water intrusion into freshwater aquifers is a major geohydraulic problem relevant to coastal environment. Apart from contaminating the fresh groundwater resources, the saltwater intrusion alters the geotechnical properties of the aquifer materials, affecting the coastal water resource planning and management. The present study focuses on an in-depth laboratory investigation of the influence of saltwater submergence on the geohydraulic properties of sand. The fine sand sample was submerged under saline water of specified concentrations for specific periods, and the alteration in their engineering properties has been studied. It is observed that the specific gravity, dry density, and permeability of fine sand is significantly affected by the period of submergence and saline concentration. The specific gravity of sand particles was observed to increase almost linearly with period of submergence and saline concentration. While the sand dry density decreased fairly linearly with the period of submergence, the same is not being affected significantly by saline concentration. The permeability of sand increased nonlinearly with both period of submergence and saline concentration; for a submergence period of 14 days and saline concentration of 30,000 ppm, the permeability increased to a maximum value.

Highlights

Accepted: 7 December 2021The term salinity may be defined as the total concentration of all soluble salts in the soil
Saline soils basically consist of chlorides, sulphates and carbonates of sodium, calcium and magnesium, with the most common salt being sodium chloride [1]
The laboratory investigations were conducted to study the influence of saltwater submergence in the geohydraulic properties of aquifer material relevant to coastal environment

Summary

Introduction

Accepted: 7 December 2021The term salinity may be defined as the total concentration of all soluble salts in the soil. The increasing demand of freshwater extraction in coastal regions initiates the saltwater’s interface to advance towards the aquifers, producing saline water intrusion [2]. Such intrusion contaminates the fresh groundwater making it significantly unsuitable for human, irrigation, and industry usages, and alters the geotechnical and geohydraulic properties of the aquifer materials, affecting the pumping and other engineering activities [3,4,5]. The alteration in the engineering properties of aquifer materials due to saltwater intrusion affects the coastal groundwater management and modelling significantly, the investigations to cover this study area have been rather limited [14]

Methods

Findings

Discussion

Conclusion