from normal groundwater recharge. During the
dry periods, the volume of seawater into the
mining pit exceeds the groundwater table with
leads to significant increase in the salinity. When
the beach and coastal dune becomes flat, the
infiltration of seawater is increasing and rising of
water to the surface in the mining region. Most of
the water infiltrates rapidly into inland sand
above the water table causes high salinity.
Extensive exploitation of coastal aquifers that are
hydraulically linked to the sea usually results in
deterioration of groundwater quality due to seawater intrusion. In the mining process freshwater
being used for mineral extraction in the region
between Kuttam and Navaladi. Mineral free sand
in these regions will be dumped back in the form
of slurry to the mined-out pits along with the
freshwater which will be about 40–50% of total
volume and it is a continuous daily process.
Thus, the loose sand is filling the mined pits and
pumped water percolating the sand and reaches
the water table. Requirement of water for mining
Fig. 14.10 Tidal-induced pressure and temperature fluctuation in Vembar estuary
198
S. Selvakumar and N. Chandrasekar