Uploaded by JESSA BLANZA


A Case Study Presented to the
Faculty of the School of Engineering and Architecture
University of Baguio
In Partial Fulfillment
Of the Requirement for the Course
Hydrology 1
Jessa R. Blanza
2 December 2020
A prolonged period with less than average amounts of rain or snow in a particular region which is
known as drought, caused by drier than normal conditions that can eventually lead to water supply
problems. Drought is a normal, recurring feature of climate and can occur in high and low rainfall areas.
Really hot temperatures can make a drought worse by evaporating moisture from the soil. But droughts
don't just happen in hot and dry places. Rain can help during a drought, but it doesn’t make the drought
go away. A light rain shower might cause the grass and plants to green up. But if that water quickly
evaporates into the air or is soaked up by plants, the drought relief doesn’t last long. A thunderstorm can
bring lots of rain into a region, but often the rain comes so quickly that it goes into sewers and ditches
instead of soaking into the soil. In fact, if a thunderstorm suddenly hits a region experiencing drought, it
can cause a flash flood. Unlike other natural disasters such as floods, hurricanes, forest fires and
earthquakes, drought onset is slow, occurs over an extended period (many months to multiple years), and
the impacts can be felt well beyond the location of occurrence. Quantifying the beginning and ending of
drought is often very difficult.
Drought in the Philippines
Drought is a natural disaster of significant concern in the Philippines. Although the Philippines is
a warm tropical climate country receiving up to 950 – 4,000 mm of average annual rainfall, El Nino events
have triggered extended periods of well below average rainfall leading to major water shortages and crop
losses. Other impacts from drought in the Philippines include grass and forest fires, food shortages,
reduced hydropower generation, loss of income and increased crime rates. The high incidence of poverty
(around a quarter of the population) and malnutrition in the Philippines compounds the impacts of drought.
In 1997–1998, the Philippines was hit with the impacts of El Niño, the most grounded of that
century (Hilario et al. 2009). During that period, the severe drought affected over 70% of the nation and
brought about harms, for example, water deficiencies and losses in rice and corn worth PhP3 billion. The
solid El Niño of 2015–2016, which is frequently contrasted with the 1997–1998 event, also had severe
impacts on the Philippines. On December 2015, the United Nations Economic and Social Commission for
Asia and the Pacific (UNESCAP) and the Regional Integrated Multi-Hazard Early Warning System for
Africa and Asia (RIMES) claimed through their advisory that the Philippines would be severely affected
by El Niño (UNESCAP and RIMES 2015). History has shown that El Niño can reduce monthly rainfall
in the Philippines by 50% during the peak periods of El Niño, which affected crop production and water
availability for consumption.
In 2015, the Philippine Government responded to this dilemma by setting up an El Niño Task
Force headed by the National Economic and Development Authority (NEDA). A Technical Working
Group was convened by NEDA to formulate the Roadmap to Address the Impacts of El Niño (RAIN).
The RAIN covered four dimensions, namely food security, energy security, health, and safety, and focused
on 67 provinces that were projected to be most likely affected by El Niño, including Metro Manila (NEDA
2017). While El Niño is often associated with decrease in precipitation, water security was not part of the
RAIN program of action.
Agriculture, and especially rice due to its high water requirement and the timing of sowing, is the
most impacted sector when drought hits the Philippines. Corn is also impacted. The sowing and growth
of the second rice and corn crops traditionally occurs in the months when El Nino rainfall shortages are
the largest (October-March). Every past drought has impacted agriculture but at varying levels of intensity
and different locations. An estimated USD 370 million in agricultural damages have been estimated for
all the ENSO events between 1990 and 2003 (Department of Agriculture 2010). The worst two droughts
were those of 1997-1998 and 2015-2016 so these can be used as benchmarks for extreme severity of
impact from past droughts. Droughts have had severe economic consequences on the Philippines
economy, particularly to the agricultural sector which accounts for 10% of GDP. The crop most vulnerable
and most impacted is rice. Other sectors, especially water, energy and human health have been heavily
impacted by past droughts.
Influence of El Niño on Rainfall in the Philippines
In the Philippines, significant changes in rainfall, a main driver of climate variability, can have
serious impacts on the country. One physical phenomenon that has a strong impact on rainfall in the
Philippines is the El Niño Southern Oscillation (ENSO).During an El Niño event when ENSO is in its
warm phase, the higher than average sea surface temperatures (SST) over central and eastern equatorial
Pacific Ocean affect the spatial distribution of rainfall such that drier conditions are experienced over
different parts of the Philippines, as well as, other areas in the western Pacific, particularly during its peak
around December to February.
Focusing on the key urban areas in this study, the monthly rainfall anomalies were obtained for
Metro Manila, Metro Iloilo, and Metro Cebu. Rainfall anomalies at Angat reservoir were also examined
since this is the source of water supply for Metro Manila. Oceanic Niño Index (ONI) measures the
magnitude of an El Niño/La Niña event and is derived from a three-month running average of SST
anomalies relative to a centered 30-year reference period over the Niño 3.4 region. Using this index, El
Niño (La Niña) periods can be identified when the ONI is above +0.5 °C (below −0.5 °C) for at least five
consecutive seasons.
The drought impacts brought about by El Niño can be compounded by urbanization and
development associated with land use change and urban heat island effects. Studies have indicated changes
in local climate (such as temperature, rainfall, circulation) due to modifications in the surface
characteristics. In Metro Manila, a warming rate of 0.8 °C per year from 1989 to 2002 was estimated due
to its urbanization. Furthermore, slow onset droughts due to future climate change can exacerbate the dry
conditions during El Niño.
Social Impacts of Drought
Hasty urbanization and continued economic expansion have increased the demand for water in
Philippine cities (Albert 2001). The urban–rural growth differentials (1950–2050), urbanization in the
Philippines has been running at a fast pace and achieving its urban transition in the early. Furthermore,
urbanization, population growth, and land use changes have also led to excessive groundwater extraction
and eventually land subsidence in the coastal areas of the metropolis (Rodolfo 2014). But access to basic
services like potable water had not kept up with the growth of urban centers. Access to potable water and
environmental sanitation services was most acute among urban poor communities in Metro Manila, Metro
Cebu, and Metro Iloilo.
Moreover, the supply of water has also been compromised by climate events like heavy rainfall
and flooding, sea level rise (SLR), and drought. During the warm months from March to May, and
especially during the El Niño years, access and affordability of water become a major challenge for city
mayors and disaster risk reduction and management offices (DRRMOs). More significantly, the dwindling
supply of potable water to the metropolitan areas hits most the vulnerable population like the urban poor.
During El Niño periods, this often leads to increasing costs of water, further compromising the urban poor
communities’ access to sanitation and other services. Droughts, then, and the consequent dwindling water
supply become major concern for local officials and on the risk governance of cities. Thus, urban service
deficits become acute during the drought periods as experienced in 1997–98and 2015–2016, deemed the
worst El Niño years.
The families’ main sources of water or delivery lines also indicate the level of development of
their communities. In Metro Manila, for instance, almost three-fourths (75%) of the households have
individual private connections or water piped into their homes, but only less than one-half (45%) have
piped water in Metro Cebu and much less (21%) in Metro Iloilo. Some of them shared their faucets with
other families/households (15% in Metro Manila, 10% in Metro Cebu but only 4% in Metro Iloilo). In
Metro Iloilo and Metro Cebu, about 18 and 12%, respectively, obtained their water from rivers or streams.
In the former, slightly more than a quarter (26%)shared their water access through a tube or piped well,
while in the latter, only about10% did. Interestingly, some families access their water supply by buying
from peddlers or vendors (Metro Cebu, 5%, Metro Manila, 4%, and Metro Iloilo, 3. 5%).The latter group
pays the highest price for their water. Ironically, they also come from the lower-income decile groups,
who cannot afford individual pipe connections to their abode.
Drought planning, including preparedness and risk mitigation measures, will help to reduce the
impacts and enhance human well-being and security during and after drought. Preparing for drought and
reducing the risk and mitigating the impacts of drought are paramount given the high incidence of land
degradation and human poverty and malnutrition in the Philippines. This National Drought Plan for the
Philippines aims to document the risk of drought and outline a series of approaches and actions the
Philippines can take to prepare for and increase resilience to drought. This National Drought Plan brings
together the key government agencies and private sector organizations to take a proactive approach to
drought management and develop appropriate response actions when drought occurs.
The Philippines has a number of existing plans and policies aimed to enhance water security,
reduce risks associated with natural disasters, conserve natural resources, increase national wealth, and
increase the nation’s resilience to climate change – all of which are directly relevant to national drought
planning and risk reduction.
The overarching water law is the Water Code (1976) that governs the access, allocation and use of
water and establishes the National Water Resources Board (NWRB) as the key regulator of water
resources (Rola et al. 2016). The Water Code established the rules on the extraction and use of all waters:
the control, conservation and protection of waters, the watershed and related land resources; and the
administrative and enforcement of these rules (Rola et al. 2016). During periods of drought or water
scarcity, the Water Code prioritizes the use of water for domestic use, followed by irrigation and other
uses. Hall et al. (2018) recently summarized the roles of the key agencies who have responsibility for
water resource management, which are important to highlight here because each will have a function
during periods of water shortage. The roles of the key agencies are (from Hall et al. (2018)):
Metro Manila is an urban center based in the National Capital Region (NCR) made up of 16 cities
and one municipality, which each having their respective local governments. However, when it comes to
risk reduction in major thoroughfares, the functions shift to the regional level, leaving the responsibilities
with the Metro Manila Development Authority (MMDA).
Historically, two concessionaires, namely the Manila Water Company, Inc. (MWCI) and the
Maynilad Water Services (MWSI), provide water and sewerage services in Metro Manila. Both these
private concessionaires invested heavily for their capital expenditure programs (e.g., pipe rehabilitation
and extension projects, refurbishment, and construction of water reservoirs and pumping stations,
development of new water sources). According to the concessionaires, there are no new water sources to
meet the increasing demand for water in the coming years. Thus, they have concentrated their investments
on non-revenue water reduction initiatives to meet the increasing demand for water because 97–98% of
the water used in the metropolis comes from Angat Dam,Metro Manila’s long-term water security is
questionable. Located about 40 km north-east of Manila, this multi-purpose dam completed in 1967 also
provides water for irrigation and hydropower generation. Although the MWSS has been planning to build
a new dam since the mid-1990s to augment the current water sup-ply, this plan has been repeatedly
postponed. Thus, MWSS plans to upgrade the older aqueducts to respond to the projected water demand
increases in Metro Manila.
Metro Manila and Angat have experienced dry conditions in the past El Niño events. During the
El Niño years, MMDA did not respond with very concrete policy actions contrary to its response in 2010
when Angat Dam reached critical water levels. Manila, Caloocan, Malabon, Pasay City, Parañaque,
QuezonCity, and Navotas areas, served by water concessionaire Maynilad Water Services, Inc., were
severely affected. According to Maynilad, 45 barangays were without water supply. Water rationing
became the preferred immediate response by LGUs. Apart from this, Caloocan City encouraged water
conservation while Quezon City also emphasized on the prevention of water leakages
In response, MWSS concessionaire Manila Waters, which serves some 125,000households,
developed a mitigation plan that included the intensification of the leak repair programs, the reactivation
of deep wells for possible supply augmentation, and the implementation of supply and pressure
management schemes, among others (Manila Water Company Inc. 2015)
Iloilo City, one of those areas severely affected by the dwindling supply of water during droughts,
the city experiences significant reductions in rainfall during El Niño periods, similar to Metro Manila.
During the 2015–2016 El Niño, Iloilo province declared a state of calamity and mobilized Php33.7 million
of their provincial fund to mitigate El Niño impacts. Iloilo City has declared water-related crises over the
recent years: A State of Imminent Calamity in 2007 and a State of Water Crisis in 2009. However,
both cases, there was barely any interest in the impacts of drought brought by El Niño to highly urbanizing
cities (HUCs) like Iloilo. It appears that droughts and regular episodes of El Niño remain a disaster hidden
from the consciousness of local officials and planners in Iloilo and those in the rest of the country.
Desalination of water is resource intensive. First, the water needs to be boiled, converted to steam
and then condensed. This requires a significant amount of fossil fuels to produce heat. But hope is still at
hand as the developments in the field has made filters made up of graphene that can desalinate water with
nothing more than hydrostatic pressure.
Rainwater harvesting has seen significant development lately and this is something everybody
ought to adopt. With rainwater, homes can store the water they get from downpour and afterward use it
when they need it in dry conditions. In urban areas, only 15% of rainwater enters the ground while in rural
areas 50% of rainwater is absorbed into the ground. Rainwater harvesting provides both urban and rural
areas with an efficient option to store rainwater and then reuse it in times of drought. If a house has a
primary water source, then rainwater harvesting provides them with an auxiliary option that they can use
when water is not available. Rainwater harvesting is a great way to combat drought and is now encouraged
among farmers and herders to provide their agriculture with water in times of drought.
Drip irrigation hopes to achieve optimum water delivery for plants and optimum moisture in the
soil. The advantage of such a system is that it does not result in water wastage. Nowadays, many
companies have come forward providing the market with cost-effective and intuitive drip irrigation
systems. Technologically advanced farms are moving towards IoT inspired drip irrigation systems that
can operate without human intervention. The highly targeted nature of drip irrigation ensures that each
plant gets the right amount of water delivered right on its roots.
Crop Engineering is also a solution to drought. We can build new mechanisms outside of the plants
to keep them watered and safe from drought, but we could also genetically engineer them to be resilient
to conditions where the water content in the soil is very low. Food production is a crucial part of keeping
the population alive. However, droughts can affect the productivity and tip the balance of food available
to the masses. Crop engineering hopes to tweak the genetics of existing crops to help them increase their
yield and provide them with better resistance to drought. A research project from Realizing Increased
Photosynthetic Efficiency (RIPE) has successfully improved corps in the way they use water, up to 25%
more efficiently. Researches have been done by various organizations around the world in efforts to
engineer crops that can withstand the harshness of droughts.
Lastly, planting tree is the best way to reduce damage from drought, improve the quality of the
environment and increase the success of precipitation. Many countries have started their efforts by turning
arid lands into forested by planting trees and saplings.
Drought vulnerability in the Philippines is compounded by the poor economy and the subsistence
nature of agriculture, whereby cropping is small scale and may often only be sufficient to feed the farmer’s
immediate household. Preparing for drought and reducing the risk and mitigating the impacts of drought
are paramount given the significant vulnerabilities in the Philippines.
Urbanization, population growth, and the rapid economic expansion of the metropolitan areas of
the National Capital Region (NCR or Metro Manila), Metro Iloilo, and Metro Cebu have also increased
the demand for water. During El Niño periods, the demand for water hits crisis proportions and usually
leads to a declaration of a state of emergency or calamity by the mayor, the head of the DRRMO. The
implementation of the plans that need massive capital investments in infrastructure development and
capability building poses great challenges for both national and local governance systems. But the
Department of Interior Local and Government (DILG), which mandates all LGUs to have their LCAP
formulated and implemented alongside the Philippine Disaster Resilience Foundation initiative of the
private sector, provides some hope for more responsive water governance.
Drought can’t be predicted and prevented since it’s a naturally occurring climate patterns and
humans have no direct ability to influence its onset, intensity, or duration but it can be assessed, mitigated
and solutions can be planned beforehand to minimize its effects to a certain region specially to places that
are most affected by drought.
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