Home' Partners : Partners February 2010 Contents Limits to future groundwater extraction
were projected. A crucial component of this
management is educating farmers so that
they recognise when overuse is occurring
and have the ability to undertake immediate
remediation practices. The project team
focused on engaging farmers in planning
and management, to ensure that the farmers
themselves were able to become resource
managers for the aquifers.
In June 2008, a farmer-managed
groundwater system (FMGWS) in the project
sites was implemented as a key component of
the management strategy. This approach has
been designed to increase farmers' awareness
and understanding of groundwater and its
occurrence, cropping pattern development
and other technological concepts, leading
to a more sustainable management of the
An important element in management
is reducing competition in groundwater
extraction during the dry season. A coordinated
pumping schedule could significantly reduce
pressures on the aquifers.
Training modules suited to the needs of
smallholder farmers, including elements unique
to the Philippine setting and culture were
With these modules, several other sub-
modules expressed in local dialect were
developed. From January to June 2009 FWS
classes were conducted at both project sites.
The result of this engagement with farmers
has been a Covenant of Support to protect
and manage the shallow groundwater
resource. This covenant was presented to local
policymakers who showed their willingness
to provide a parallel effort to protect and
manage the shallow groundwater resource by
espousing related local policies. Furthermore,
it was agreed that this should be referred
to the National Water Resources Board,
the agency that regulates the utilisation,
protection and management of Philippine
water resources. n
PARTNERS NOVEMBER 2009 FEBRUARY 2010
province experiences two distinct seasons: wet
from May to October and dry from November
to April. The wet-season rainfall ensures lowland
agricultural production and also recharges
Before vegetable cropping, rainfall had been
sufficient to ensure that irrigation from pumped
groundwater was needed only at the beginning
of the dry season, to finish rice crops.
The main barrier to increased vegetable
production has been the cost of pumping
groundwater, as the diesel-fuelled pumps
are expensive to run. Electricity is a cheaper
source of power but has not been available
in Pasuquin and Burgos municipalities,
A new wind-turbine power station near
Burgos is making electricity more widely
available and reducing pumping costs. As a
consequence newer, deeper-drilling pumps are
becoming cheaper, threatening to significantly
increase rates of water extraction.
The dangers of over-exploitation of
groundwater include wells running dry,
reduced crop yields or total failure, rising
salinity and saline intrusion and, potentially,
land subsidence. Finely balanced aquifers can
reach levels of over-extraction quickly and
once an overdraft of water occurs, a return to
sustainable management is difficult.
Avoiding over-exploitation through
management has been a goal of the Philippines
Government and local authorities. However,
their expertise was in the sand-based coastal
aquifers common in the country, whereas the
aquifer in Ilocos Norte is limestone.
ACIAR funded a project, partnering
Australia's CSIRO Land and Water with
the Philippines Bureau of Soils and Water
Management, to develop planning and
management options before groundwater
depletion became unsustainable.
Without planning and management, poverty
reduction and food security, respectively, would
be threatened. While poverty may increase
in the short term, as income from vegetable
production is lost, food security could be
compromised if in the long term groundwater
became unavailable to finish rice crops and if
wells providing household water ran dry.
The project team found some good news
for smallholders: the combination of limestone
aquifers and available run-off in the wet season
suggested that a management plan for water
recharge could protect the aquifer and still
potentially support production even if a water
overdraft were to occur.
To achieve this, a topographic survey was
undertaken at project sites in Pasuquin and
Burgos. The location of wells was mapped and
combined with soil and land-use surveys and
geological investigations to draw a complete
picture of water use and aquifer health.
Watertable maps and salinity maps were
then prepared, and water chemistry analysis
undertaken. The survey of wells revealed 546
across the two project sites, with 355 wells used
for household water and the remaining 191
used for irrigation.
Water in the aquifers fluctuated by as much
as 3.5 metres at Pasuquin and 2.5 m at Burgos.
Of total rainfall, about 10% of falls recharged
Pasuquin's aquifers and 13--17% recharged the
aquifers at Burgos.
Once a total picture of water resources was
drawn, three groundwater models were used
to forecast differing levels of sustainability.
Four future scenarios were developed for
each project site that modelled specific
combinations of increased groundwater
extraction, reduced recharge due to anticipated
climate change impacts, and recharge
augmentation. From the three models, one was
chosen for each of the two project sites as the
basis for economic modelling to demonstrate
examples of increased or more efficient
groundwater extraction and the resulting
potential economic opportunities.
For example, in Pasuquin modelling
of sustainable groundwater extraction
demonstrates that about 90 hectares can be
used for intensive garlic production in suitable
areas in the dry season. This would involve
relocating some production to more suitable
soils, with a production increase of some
810 tonnes per year, representing an estimated
28.4 million Phillipine pesos in income.
The equivalent model for Burgos indicated
that sustainable extraction was best in the
mid-range of predictions relating to water
usage, and could support some 60 hectares
of intensive garlic production, yielding about
186 tonnes for a return of PHP11.1 million.
Differences in production levels and returns
are due to the soils in Burgos being only
moderately suited to garlic production and
evidence of increasing salinity during pumping.
Pumping of groundwater during the dry season must be
done sustainably to ensure long-term use.
Without planning and
management, poverty reduction
and food security, respectively,
would be threatened.
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