Geology Reference
In-Depth Information
Figure 1.
Simulation of water table levels in Maheshwaram watershed
according to Rainfall scenario (substituting the 20 previous rainfall
years for the coming 20 years).
the current pumping is maintained. This scenario will also entail the loss of
about 50% of the bore-wells with accompanying serious socio-economic
consequences that the reader can easily imagine (rural exodus, poverty,
diseases, etc.). This limit will be reached by the year 2009 if the groundwater
exploitation by pumping continues at the present rate of development.
Unfortunately, recent information (complaints from the farmers and recent
hydraulic tests) from the studied area is in accordance with the first scenario:
strong decrease of the yield of numerous bore-wells and sometime drying-
up.
Considering no change in both groundwater abstraction and cropping
pattern, Fig. 2 presents simulations with two different climatic conditions:
one with two consecutive weak monsoons (annual rainfall: for 2005 =
450 mm and for 2006 = 400 mm) and the other with two consecutive good
monsoons (year 2005 = 1000 mm and year 2006 = 1100 mm). The simulated
groundwater levels show that whatever the monsoon, the problems will
occur sooner or later, and maybe faster than expected. Drying up of bore-
wells are about 50% in 2006 in case of 'weak' monsoons and about 40% in
2014 in case of 'good' monsoons. These simulations as well as the ones
presented in Fig. 1 show that immediate action is required.
Impacts of changing cropping pattern and artificial recharge on ground-
water levels as well as groundwater budget clearly show that this catchment
is overexploited. To avoid a dramatic situation in this area in the near future,
decisions have to be taken to improve the groundwater management. As the
area is overexploited, either the evapotranspiration of irrigated crops has to
be reduced (decrease PG-RF) or/and additional artificial structures have to
be implemented. However, the authors want to point out that building large
