Geology Reference
In-Depth Information
(shallow), buried pediments (medium) and valley fills. Depositional processes
also develop landform namely valley fill. The weathered pediments buried
under soil cover represent the features formed by the involvement of both
erosional and depositional process.
Buried Pediments (Shallow) [BPS]
This unit is basically a pediment zone and consists of very low weathered
zone. A flat and smooth surface of buried pediment consists of shallow
overburden of weathered derivative material. Groundwater prospects are
moderate to poor, but open wells yield good amount of potable water after
monsoon (Shah, 2001).
Buried Pediments (Medium) [BPM]
These units are moderately weathered with their thickness greater than that
of the shallow pediments. A flat and smooth surface of buried pediment with
moderately thick overburden of weathered derivative material. Groundwater
prospects are also good to moderate.
Valley Fills [VF]
Valley fills are linear depressions present in between the hill ranges and
occupy the lowest reaches in topography, commonly filled with pebbles,
cobbles, gravel, sand, silt and other detrital material. The groundwater potential
ranges from moderate to good. These valleys are developed along the fractures
and such places can be exploited for groundwater through deep bores. In
general, it is observed that adequate recharge source of groundwater is met
within valley fillings. Hence, in such places, the groundwater is considered
to be moderately better with adequate source of water. This has very good
porosity and permeability but some time presence of clay may make it
impermeable.
The details of various geomorphic units and their groundwater bearing
prospects are given in Table 1.
Table 1:
Hydrogeomorphology and groundwater prospects
of various geomorphic units
Geomorphic Units
Description
Water Prospects
Valley Fill
Accumulation zone of colluvial materials
Good
derived from surrounding uplands; shallow
to deep; fine loamy to clayey soils.
Buried Pediment
Gently sloping topography; very deep,
Moderate
(Medium)
clayey to fine loamy soils.
Buried Pediment
Nearly flat to gently sloping topography,
Poor
(Shallow)
shallow to moderately deep, loamy soils
followed by regolith zone.
