EIA Studies of 3 Pre-Identified Hazardous Waste Disposal Sites in ...

Rapid EIA Studies of 3 Pre-identified Hazardous Waste Disposal Sites in NCT - Delhi:
Page No.59
alluvial deposits are grey coloured sands containing minor proportions of fines i.e. silt
and clay. These deposits are generally characterised by the absence of kankar.
Newer alluvium at some places consists of coarse gravel which is irregular and
poorly sorted in nature. The older alluvium consists of inter-bedded, lenticular and
inter fingering deposits of clay, silt and sand ranging in size from very fine to medium
textured. Kankar which is generally hard, compact and irregular occurs mixed with
almost all these deposits. Older alluvium is predominantly clayey in nature.
Sub-surface Geology
There are possibilities of fresh groundwater aquifers in this area as per Central
Ground Water Board's findings. Sand, medium to coarse grained, admixed with
varying proportions of Kankar horizons dominates at shallow depths in and act as
moderately potential aquifer zones. These sand horizons of varying thickness from 3
to 15 m are predominant upto a depth of about 70 to 75 m at Bawana, 112 m at
sanoth and up to 88 m in Barwala. Thin clay layers of about 5 to 10 m thick separate
these sand bodies. At Putkhurd the sand horizons of 5 to 10 m thick are separated
by clay layers of about 3 to 15 m thick. At Holambi kalan the sand bodies of about 5
to 20 m thick up to a depth of 86 m are separated by clay layer of about 5 to 7 m
thick. The clay horizons are invariably present after 80 to 112 m and seems to
persists to considerable depth. The sub-surface geology across the section of
Sanoth to Khera Kalan shows that newer alluvium is present in southern part with
depth ranging up to 20 m at Khera Kalan. At Sanoth, the older alluvium consisting of
silty sand mixed with kankar is present up to a depth of 84 m and at Khersa kalan it
is up to a depth of 70 m. Below this horizon, alluvium is predominantly clayey mixed
with kankar and minor silt is present. Five to six intercalations of silty sand mixed
with kankar horizons are present as lenses within the clayey horizons. Thickness of
these lenses is 5-7 m.
Around Site II: Wazirpur CETP site
Wazirpur Industrial area is occupied by Quaternary Alluvium underlain by the Alwar
Quartzites of Delhi System. Thickness of alluvium is more than 300 m in this part of
Delhi. Alluvium consists of predominantly silt and kankar mixed with minor amounts
of clay. Silt mixed with kankar that acts as very good aquifer system in the area
usually extends in-between the depth of 25 to 30 m. Good aquifer system extending
from 40 to 50 m depth consists of predominantly kankar with minor silt is present in
the area.
Around Site III: Guman Hera CETP site
The area is underlain by older alluvium mainly consists of unconsolidated, inter
bedded sand, clay and silt mixed with varying proportions of gravel and kankar. The
top horizon is predominantly sandy silt mixed with kankar extends down to a depth of
30m. This layer is followed by predominantly clay layer at deeper levels. Thin
granular zones consisting of silt and kankar are also present with in the clay layer
extending from 30 to 50 m depth. Thickness of these granular zones are increasing
towards Najafgarh drain. Ground water occurs as unconfined condition in sandy silt
horizon which are potential aquifers in the area.
Environment Division, National Productivity Council, New Delhi
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