Geoscience Reference
In-Depth Information
The Kunderu basin is further divided in to eight subbasins namely Galeru
(I), Madieru (II), Kollamvagu (III), Palleru (IV) Jerruru (V), Palieru
Peddavanka (VI), Vakileru (VII), and Tigaleru (VIII) as shown in Fig. 1.
The average recharge values obtained from injected sites in these subbasins
are 20.4, 59.3, 17.5, 44.1, 49.3, 38, 12.3, and 37.1 mm, respectively. Few
sites in the basin show negative recharge. These are sites where practically
negligible or no recharge takes place (discharge area).
Raju and others
10
have indicated that greater than 5% slope cannot hold
surface water for sucient time to allow the percolation and so the area
above 5% slope can be neglected for calculating the effective recharge area
in a basin. Using this criterion, the effective infiltration area of Kunderu
basin was calculated as 7,241 km
2
. In total 211 million cubic meters (MCM)
in Kunderu basin has been recharged to groundwater and was added to near
surface aquifers due to monsoons. This is equivalent to average net recharge
of 0.029 MCM over an sq. km area.
The recharge estimates at Kunderu river basin from 46 sites range from
−
25
.
8 to 94.3 mm with a mean value of 29 mm. This is 4.7% of the monsoon
rainfall of 615 mm. The measured recharge value shows a wide scatter, rang-
ing from 29 to 179 mm. This is due to variation in pattern and magnitude of
rainfall, change in soil type and its heterogeneity. The total annual input to
groundwater reserves of Kunderu river basin due to monsoons rains over an
effective infiltration area of 7,241 sq. km was 211 MCM. The reproducibility
of recharge measurements obtained by tritium injection method has been
found to be +10% from the mean. The sites found, through tritium injec-
tion studies, to be giving high recharge values, can be considered favorable
for implementation of schemes of artificial recharge.
Acknowledgments
The authors wish to thank to Dr. V.P. Dimri, Director, NGRI, Hyderabad
for his kind support and his permission to publish this paper.
References
1. S. Balakrishna, B. Venkatnarayana and M. N. Rao,
IIPG
, Hyderabad, 1979.
2. I. Radhakrishna,
IIPG
, Hyderabad, 1982.
3. U. Zimmermann, D. Ehhalt and D. O. Mummich,
Isotopes in Hydrology
,
IAEA, Vienna, 1967a, pp. 567-586.
4. U. Zimmermann, K. O. Munnich and W. Roether,
AGU Geophysical Mono-
graph
11
(1967b) 28-36.
