The water
Resource Ministry of Government of India has released a notification and a fact
sheet on National Aquifer Mapping Programme (NAQUIM). The Central Groundwater
board and the State Groundwater Departments will act as the main functionaries
in this programme. It is also decided by the government that national level
aquifer mapping will progress substantially through the 11th five
year plan period. Considering the fact that those government departments alone
cannot accomplish the job it has been decided that stake holders and NGOs would
be involved in this endeavor. This
national level programme also has components like nation wise training and
human resource development.
But, what is an
aquifer map and what it is for?
The concept of
aquifer mapping is not new. Many developed countries like Australia and USA
have already completed aquifer maps in certain areas like Murray Darling Basin
and Texas. They have already published some of the reports and maps. An aquifer
map is not a single map, on the other hand it is a group of several maps that
would describe the aquifer system and management criteria and options in an
area.
In NAQIM
programme of India it has been proposed that aquifer maps would include (1)
Identification of Aquifer Management Units (AMU) (2) Evaluation of AMU, (3) Data
preparation and generation of different categories (4) Prioritization of AMU,
(5) Preparation of aquifer management plans and aqifer management and
information system, (6) Participatory
groundwater management.
1.
IDENTIFICATION
OF AQUIFER MANAGEMENT UNITS:
Aquifer
management units are something different from a Hydrogeological unit. In a
hydrogeological map generally geological units are described by its
hydrogeological characteristics. But an AMU contains much more than that. It
includes the 3 dimensional matrix of all information like extent of the
aquifer, depth, thickness, geology, hydrology, land use on it, recharge and
discharge related information and its political and social boundaries.
2.
EVALUATION
OF OF AMU:
This
is the most difficult task. Aquifer
evaluations are conducted for various purposes including water supply
development as well as groundwater contamination and remediation situations.
They can range from fairly intense evaluations involving test drilling,
geophysical investigations, installation of monitoring or observation wells,
test pumping, physical and chemical water quality analyses, analytical and
digital modeling to rapid evaluations based on existing data.
3.
DATA
PREPARATION AND GENERATION OF DIFFERENT CATEGORIES:
The groundwater departments and states are
generating groundwater data on regular basis. But those data are generally categorized
on the basis of revenue boundaries and not on the basis of aquifer boundaries.
So under NAQIM aguifer
related data should be compiled and generated. A suggestive list of required
data is given below.
- Evaluation of existing data
- Test drilling
- Installation of
monitoring or observations wells
- Geoprobing and/or
hydro probing
- Geophysical
investigations
- Geophysical
borehole logging
- Groundwater
gauging
- Groundwater
sampling and analyses
- Test pumping
- Slug testing
- Analytical and
digital groundwater modeling
- Solute transport
modeling
- Groundwater
monitoring
4.
PRIORITISATION
OF AMU:
AMUs
are basically aquifers subdivided into management units. These units are
prioritized according to the demand and usage depending on the evaluated
parameters of the aquifer. Before prioritization a management framework is
required. The framework may include:
•
Establish the baseline groundwater conditions and range of natural variability
in the aquifer to facilitate enhanced knowledge and detection of change.
•
Provide a consistent approach to understanding potential effects from all
development activities on the surrounding environment.
•
Facilitate projections of change based on future scenarios, such as expanding development
or climate variability and change.
•
Support and supplement the current pollution prevention and risk management principles
as part of groundwater quality and quantity management.
Prioritisation index:
Depending on the
hydrogeology, quality of water and development status a prioritization index is
to be developed by the groundwater authorities.
AMUs are
initially ranked according to an index (equation 1) based on normalised current
groundwater extraction, the fraction of groundwater allocation currently
extracted , the fraction of sustainable yield currently extracted , a potential
growth index and an index of the predicted future impact of groundwater
extraction on surface water flow.
Apriority
evaluation index has been attempted in Murray-Darling Basin Sustainable Yields
Project (http://www.clw.csiro.au/publications/waterforahealthycountry/mdbsy/technical/Q-GMU-Prioritisation.pdf) Several other algorithms can be developed to
prioritise aquifers in our country. In a GIS platform both raster and vector based
analysis may lead to an efficient decision support system.
5.
MANAGEMENT
PLAN
This initiative will seek to protect the long term
water supply capacity of the aquifer by controlling average annual aquifer use
and balancing it with average annual recharge.
i.
Aquifer
Protection Plan: This initiative will seek to assess the quality of the water
in the aquifer and then to protect it by encouraging activities that enhance
water quality and by discouraging activities that degrade it. The key components are
ii.
Maintain
Status Quo where water level is alarmingly depleted.
iii.
Reduce
withdrawal of water: Water withdrawal may be reduced by introducing innovative
farming, recycling of water and reducing consumption. The management plan will
address aquifer specific recommendation.
iv.
Enhance
Natural Recharge: To enhance natural recharge proper steps should be taken.
This may include afforestation, gully plugging, construction of sub surface
dykes etc. This initiative will seek to maximize aquifer recharge with good
quality water by encouraging beneficial land and water management practices and
by investigating the potential to use stream flow.
v.
Monitoring
plan: This initiative will seek to maintain a current and comprehensive
scientific database on the aquifer by collecting, compiling and evaluating
data. The current aquifer monitoring activities could be reviewed to coordinate
and redesign them, focusing on the comprehensive protection of the Aquifer.
vi.
Manage
Pollution Risks:
Activities carried out in pits and dumping areas within the primary recharge
area present a variety of risks to aquifer water quality. The risks associated
with these activities could be assessed and, where required, action taken to
manage them as part of an aquifer protection plan. Other risks like geogenic
contamination like As and Fl should be properly addressed in the management
plan to reduce public health hazards.
vii. Reduce Incoming Salt Water: The regional salt water flow to the aquifer could
possibly be intercepted by installing a set of management structures or through
innovative engineering activities.
6.
AQUIFER
EDUCATION PLAN
The potential long term success of this management
plan depends on the understanding and cooperation of a diverse group of
people. It is believed that a better
informed group makes better decisions.
Only common understanding will engender the cooperation needed to
formulate, implement and maintain a
successful long term stewardship plan for the Aquifer. Additional study is
required to achieve a better understanding.
Extension education is required to make knowledge gained available to
all area residents.
