Geoscience Reference
In-Depth Information
GROUNDWATER RECHARGE EVALUATION IN A RIVER
BASIN, ANDHRA PRADESH, INDIA
RAMESH CHAND
∗
, N. C. MONDAL, V. S. SINGH and A. PRASANTI
National Geophysical Research Institute, Uppal Road, Hyderabad-500 007, India
∗
rameshtyagi@yahoo.com
The average natural recharge to the phreatic aquifer of a river basin, Andhra
Pradesh, India, is estimated using injected tritium technique. Tritiated water
was injected at 46 selected sites in this basin before the onset of monsoon
covering different soil types. Moisture content and tritium activity of the soil
core samples, collected from the injected sites after the monsoon rains were
measured. The variation in tritium activity and moisture content with depth
is used for the estimation of tracer movement and calculation of recharge. The
recharge values were found varying from 26 to 94 mm with the mean value of
29 mm corresponding to the rainfall of 615 mm. The quantum of groundwater
recharge through vertical infiltration has been estimated as 211 million cubic
meters over an area of 8,650 km
2
.
1. Introduction
Kunderu River basin located in Anantapur, Cuddapah, and Kurnool dis-
tricts of Rayalaseema region of Andhra Pradesh (India) was selected for the
estimation of recharge potential. The climate is semi-arid and this basin is
chronically drought affected due to frequent failure of monsoons in the last
decade. The surface water resources are limited to the quantum supplied
through the Kurnool-Cuddapah canal in the Kunderu basin. There were
curtailments in these supplies too, owing to depletion in reservoir storage.
As such large areas of the basin depends only on the groundwater supply.
The prime source of recharge to groundwater in the basin is by direct pre-
cipitation due to annual rainfall. Due to non uniform recharge conditions
and precipitation, large fluctuation in groundwater levels are often observed
at many places. It has, therefore, become essential that the annual input or
recharge to various aquifers of this basin is quantified and the data is used
for planning and optimal utilization of the groundwater resources.
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