Accepted Papers - 3.pdf - UNESCO

ground water recharge, which includes analysis of
rainfall data for 12 years to assess recurrence and
magnitude of drought then, water requirement for
irrigation and drinking water, surface runoff, surplus
and deficit situation has also been analysed. The
findings are presented below.
Rainfall Details
The area receives rainfall from southwest
monsoon and to some extent eastern depressions
bring rainfall to the district. Average annual rainfall
in the district is 1363mm. However, the rainfall data
of last 12 years (1992-2004) indicates a low average
rainfall of 1063.21 mm. The average rainfall of
Mahasamund Tehsil is lowest i.e., 750.8 mm
followed by Basna 1142.1 mm and Saraipali 1296.65
mm. Twelve years average annual rainfall in
Mahasamund Tehsil of the district is shown in
Table - 2
The rainfall data of last 12 years are already
presented Table-1, which indicates that the average
rainfall in the watershed is 750.8 mm during the last
decade. The analysis of the above data indicates that
the area is drought prone as there are 8 years in the
last decade, wherein, the rainfall was lower than the
decadal average of 750.8 mm, in which the rainfall
in 1999 was 378.3 mm. However, in the 4 years the
rainfall was above average and in the year 2003 the
rainfall was as high as 1841.2 mm. Thus, there are
three distinct situations, i.e., year of very low rainfall,
moderate rainfall and high rainfall.
Ground Water Recharge Assessment
In view of this the ground water recharge in
the study area has been worked out based on aquifer
characters.
[A] Recharge in mcm
(Through Rainfall) = Area of the watershed (in
sq km) x Aquifer thickness (in meters) x
Storage coefficient
= 125.82 x 3 x 0.03
= 11.32 mcm
[B] Recharge in mcm
(Through Water Bodies) = Water spread Area
(in sq km) x Recharge factor (in meters)
= 1.77 x 0.60
= 1.06 mcm
[C] Total Recharge
(in mcm) = A +B
= 12.38 mcm
Table-2
Tehsil Mahasamund Twelve Years Monthly Rainfall
Tehsil Mahasamund Years
Since the recharge is directly related with the
amount of rainfall, there exists 3 distinct recharge
situations also, in which the recharge in drought year
is expected to be very low, in view of this it is
essential to asses the annual recharge for all the three
rainfall situations. In accordance with this annual
recharge for three situations has been worked out as
under. The recharge is calculated by rainfall method
using recharge coefficient factor as 15%. (As per
the recommendation of groundwater estimation
committee of GOI 1997).
Month 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Jun 63.9 88 322.4 149.7 20.9 33.7 87.3 129.2 107.7 438.3 117.6 250.2
Jul 217 155.1 341.2 342.4 258.6 211.6 158.2 143.1 217.4 69.1 379.9 371.9
Aug 175 199.7 259.6 201.9 142 290 63.4 92.7 107.8 235.8 680.3 218
Sept 53.9 96.8 82.6 42 29.1 67.6 67.4 108.4 38 159.4 571 124.3
Oct 7 2 51.1 38.7 92.4 38.2
510 539.6 1005.8 736 457.6 602.9 378.3 524.5 470.9 941.3 1841.2 1002.6
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