Geology Reference
In-Depth Information
found. Therefore, it is now essential that policy makers be equipped with
accurate predictive tools for simulating the groundwater table in the coming
years in order to better guide their future actions in total coherence.
The IFCGR has built up and developed a Decision Support Tool (DST)
which can easily be used by everyone, and made under Excel Software
interface which can be found everywhere on any computer. DST is now
operational in Maheshwaram and can be applied to any other watershed with
a similar context. The DST is designed for ground water scenarios under
variable agro-climatic conditions, and focuses on the importance of changing
cropping pattern and artificial recharge on groundwater levels. It is based on
the Groundwater Budget method combined with the DWTF method. The
DWTF method has been developed at the IFCGR and is specially applicable
to hard rock aquifers in a semi-arid climate. For further details about this
method, the readers are suggested to refer Maréchal et al., 2006.
The DST is composed of various active windows:
the Groundwater budget method as memo,
the various information about the studied watershed (geographical and
geological contexts, land use, etc.) including all the data related to the
components of the Groundwater budget and the different methodologies
used,
the ones for the input data related to the aquifer characteristics (specific
yield, piezometric, surface area, etc.), the in- and out-flow balance, the
irrigated crop characteristics (seasonal consumption, irrigation return flow
for each crop, and for Rabi and Kharif season),
the one to simulate the effect of different scenarios of rainfall on the
groundwater levels,
the one to simulate the effect of the changing cropping pattern and/or the
artificial recharge on the groundwater levels,
and a window for helping the user to build realistic scenarios through the
support of socio-economic and socio-cultural data.
The DST enables to input rainfall scenarios for the coming years, calculate
the corresponding recharge component, and simulate the consequences on
groundwater levels at the watershed scale as well as the socio-economic
consequences, like the impact on the population or the energy issues.
SCENARIOS USED IN DST
Considering no apparent climatic changes (same annual rainfall pattern since
the last 20 years), two scenarios are presented in Fig. 1: 'current trend' with
no change in both groundwater abstraction and cropping pattern, and 'present
rate of agricultural development' where the irrigated area is increasing at a
rate of ~1.3%/year according to FAO, 1997; cropping pattern remains also
identical. In the first scenario, the mean groundwater resource limit, below
which the aquifer cannot be exploited, will be reached by the year 2010 if
