Geology Reference
In-Depth Information
Figure 2.
Hydrographs of observation wells showing data gap.
is 750 mm. The area lies at an elevation of 600 - 670 m above mean sea
level. The area consists of hard crystalline rocks mainly pink and grey
granites of Archaean age with variable density of fractures within the
subsurface. Major part of the basin consists of biotite granite and some part
of it consists of leucogranite. Foliation of the granites is traced on outcrops
of granite. Granites with pegmatite show higher density of fractures/fissures.
The area consists of dendritic drainage pattern. Major part of the basin is
covered with pediplain having shallow weathering. Soil consisting of clay
loam, red loam and sandy loam with variable thicknesses (0-1 m) form the
top layer (Hashimi and Engerrand, 1999 and Krishnamurthy et al., 2000).
Moderate thicknesses of weathered rocks are present and thus a two-tier
system viz., weathered and fractured aquifers co-exist in the entire area. Due
to over-exploitation of the groundwater resources, the water level has gone
down and presently the groundwater occurrence is mainly in the fissured
rock under unconfined conditions (Subrahmanyam et al., 2000; Maréchal et
al., 2004).
