4.2 Ajabgarh series 
The Ajabgarh series of rocks comprise of 
carbonacious phylite, slate, thinly bedded 
quartzite, chlorite, sericite schist and 
quartzitic schist. These are better aquifers 
than Alwar rocks. There is a lack of primary 
porosity and permeability due to metamorphism, 
but secondary porosity and permeability is 
found due to joints and fractures which faci 
litates harbouring of the groundwaters under 
watertable conditions mainly. Well in these 
rocks yield discharges ranging from 3.6 to 
10 cubic metres per hour. 
4.3 Quaternary deposits 
Recent to Sub Recent deposits of Alluvium 
and loess with good primary porosity and 
permeability has high recharge potential. 
They form aquifers and contain potable to 
brackish water. Wells tapping these depo 
sits are capable of yielding good supplies, 
ranging from 30 to 40 cubic metres per hours. 
The yield of well varies from place to place, 
but generally wells located in the vicinity 
of Yamuna river and Agra canal yield more 
than other wells. 
5 GROUNDWATER POSSIBILITIES IN DIFFERENT 
GEOMORPHIC UNITS 
5.1 Structural and Denudational hills 
Structural hills of hard quartzite rocks 
form a runoff zone. However, some ground- 
water occurs and moves through joints, 
ractures and faults. Delhi quartzites with 
high relief and steep slope show high runoff 
zone and very poor recharge. No well has 
been dug in this unit due to poor aquifer 
characteristics. Near the Siva temple, 
Firozpur Jhirka, one dug well in Alwar quart 
zite is noticed. Depth to water is about 
8 metres. It is also located in the faulted 
zone of the Siva temple. A perennial spring 
is also noticed close to dug well. The well 
might be recharged through groundwater colle 
cted in fracture zone, otherwise no dug well 
has been reported. 
5.2 Pediment 
Owing to hardness of area, slope and very 
limited weathering, pediment forms mainly 
runoff zone. It possibly provides nominal 
recharge surface for lower pediment zone. 
The good quality water is found in this 
unit. 
5.3 Buried pediment 
This unit consists of clay, silt and sand 
with nominally weathered, jointed rocks. 
beneath. It is a recharge zone. Water is 
found under watertable conditions. The 
thickness of deposited materials varies 
from place to place. Depth to watertable 
varies from 8 to 20 metres. The quality of 
water ranges from potable to brackish. 
5.4 Intermonatane valley fill 
This unit consists of wind blown materials. 
The unit is located between two ridges, so 
it does not carry much groundwater weightage 
in present study area. 
5.5 Obstacle sand dunes and sandy loess 
plain (dissec ted) 
Most of the area is covered by sand. This 
area is barren and intensive gaily network 
has been developed indicating a high runoff 
zone. The material is porous and permeable, 
still owing to steep slope, there is very 
poor recharge, and almost all precipitation 
contributes for runoff. There is no culti 
vation over this unit. Water is potable 
but at places slightly brackish. 
5.6 Sandy loess plain (undisserted) 
Considerable area is covered by aeolian sand 
which is being cultivated by well irrigation 
and at some places rainfed cropping is also 
practiced. Sand is fine grained, well groun 
ded with high porosity and permeability. 
Only local development of Kankar is found. 
Depth to watertable in area ranges from 
8 to 20 metres. 
5.7 Alluvial plain 
This unit comprises of old flood plain and 
closed basin. The alluvial plain country 
is composed of the clay, silt and sand. The 
watertable varies from a few metres to 20 
metres. In old alluvial plain salt affected 
areas occur and paleochannels fills are 
having shallow watertable and good recharge. 
The good quality of water is found in paleo- 
channel. The quality of water ranges from 
potable to saline. 
6 DEPTH TO WATERTABLE AND WATERTABLE 
EVALUATION 
The depth to watertable, in general, lies 
within 8 metres below ground level in a 
large part of the area; the shallowest being 
0.2 metre below ground level and deepest 
32.85 metres. It is evident from figure 2 
that the depth to watertable is more in the 
vicinity of hilly tracts. Shallow water- 
table is found in a large parts of the area 
east to the ridges, and west to Agra canal. 
The watertable contours generally follow 
the surface topography. The altitude of 
watertable ranges from 179.6 to 281.5 metres 
above mean sea level. In the eastern part, 
hydraulic gradients are moderately steep. 
The watertable slopes southwards in the 
northeastern part of the area with an average 
hydraulic gradient of 0.6 metres per kilo 
metres. In the south western part, in the 
valley between two ridges, groundwater move 
ment is NNE with hydraulic gradient of the 
order of 1.45 metres per km. NNE - SSW 
trending ridges form a groundwater divide. 
The fluctuation of watertable is of two 
types, the long term and seasonal. Broadly, 
the seasonal fluctuations are caused by 
seasonal variation in rainfall and ground- 
water draft whereas the secular variations 
are mainly a result of groundwater develop 
ment. During the period of June 1974 to 78 
a rise in watertable has been observed in 
most of the hydrographic stations of the 
order 0.41 to 2.23 metres and a recession 
of about 1 metre in two stations. The five 
years average seasonal fluctuations in the 
various blocks of the region varies from 
1.2 to 2.5 metres. Considering the long 
term fluctuations between 1961-63 and 1975- 
76, it is seen that there is a rise in water 
level in most of the part of the region 
which ranges from 0.1 to 8.6 metres.