Where Does the Rain Go? Rethinking Water Scarcity in a Rain-Rich Philippines

By Antonina Lourdes “Queenie” E. Cunanan

Co-Founder and President, Ecosensya Solutions for Environmental Sustainability, Inc.

Every time I hear about drought, declining groundwater, or water rationing in the Philippines, I return to one question:

Where does the rain go?

We live in a tropical archipelago that receives substantial rainfall. During the wet season, we can have so much water that our concern becomes flooding. We build drains, canals and other infrastructure to move water away.

Then the dry season arrives, and suddenly the conversation changes.

Where will we get water?

Should we drill deeper?

Do we need another source?

How do we ration what remains?

I have always found this contradiction difficult to accept without asking more questions.

Are we really water-scarce—or are we failing to manage our water abundance?

I do not suggest that the answer is simple.

Water availability depends on geography, rainfall distribution, watershed condition, geology, aquifer capacity, infrastructure, demand, pollution, governance and many other factors.

Nor should we attempt to capture every drop of rain. Rivers must flow. Wetlands need water. Ecosystems and downstream communities depend upon it.

But I believe we are asking too little of another part of the equation:

How much of the rain that falls on our landscapes could we responsibly save?

A Question That Changed How I Look at Water

Several years ago, I made an exploratory calculation.

I looked at rainfall in Region IV-A, or CALABARZON, and considered the amount of open space where Nature-based Solutions could potentially be developed.

I wanted to know:

How much rain actually falls on these areas?

And then:

What if some of that rainfall could be used to recharge groundwater?

My preliminary calculation surprised me.

Under the assumptions I used at the time, the theoretical rainfall volume over approximately four months was large enough to represent groundwater recharge potential on a scale comparable with the annual water requirements of approximately 17 million people.

I want to be careful about what that number means.

It was an exploratory calculation—not a validated estimate of available water supply. A scientifically defensible assessment would need to account for updated rainfall and land-cover data, infiltration rates, evapotranspiration, runoff, hydrogeology, aquifer characteristics, environmental flows, actual water demand and many other variables.

I intend to revisit and scientifically validate that work.

But something more important than the number stayed with me.

It changed the question.

Instead of continually asking:

“Where can we find more water?”

I began asking:

“What are we doing with the water we already receive?”

The Philippines Should Think Differently About Rain

I have a provocative personal view.

The Philippines should aspire to become water-positive.

Perhaps our long-term ambition should not simply be to avoid drought and water rationing.

Perhaps a rain-rich country should become exceptionally good at managing water abundance.

I sometimes take this thought even further: if we managed our water resources extraordinarily well, could we someday think not from a position of scarcity, but of surplus—even of water as a resource we could potentially share or export?

That is a vision, not a claim about our present water balance.

But I believe ambitious questions are useful because they force us to reconsider assumptions we have learned to accept.

Why should flooding and water scarcity repeatedly exist in the same landscape?

Why do we treat rainwater as a problem when there is too much of it, but search for water when there is too little?

What happens to the enormous volume of water that falls between those two moments?

And most importantly:

Can we design our landscapes differently?

Bank the Rain

This thinking led me to a simple analogy.

We save money when we have it so that it is available when we need it.

Why don't we think about rain the same way?

Imagine rainfall as a deposit into a landscape's Water Savings Account.

Healthy soil can hold some of that deposit.

Vegetation can slow it.

Wetlands can retain and filter it.

Ponds and tanks can store some of it.

Suitable open spaces can allow infiltration.

And, where hydrogeological conditions permit, aquifers can receive recharge and provide longer-term storage.

Of course, a responsible savings account also needs withdrawals and obligations.

People need water.

Farmers need water.

Industries need water.

Rivers need water.

Wetlands need water.

Nature needs water.

So Bank the Rain does not mean capturing everything.

It means understanding the water balance well enough to ask:

How much can we responsibly retain today so that both people and nature are more resilient tomorrow?

Nature Is Infrastructure Too

For a long time, infrastructure has often meant concrete.

Concrete is necessary. Engineering is necessary. Dams, drainage systems, treatment facilities and distribution networks all have important roles.

But they are not the only infrastructure available to us.

Soil is water infrastructure.

Forests are water infrastructure.

Wetlands are water infrastructure.

Farms can be water infrastructure.

Open spaces can be water infrastructure.

Aquifers are natural water banks.

This is one reason I became deeply interested in Nature-based Solutions, or NbS.

Nature-based Solutions do not mean abandoning engineering.

They mean asking whether natural processes can perform some of the functions we need—and how nature and engineered systems can work together.

At Ecosensya, this has increasingly led us toward decentralized water solutions.

Rather than expecting one enormous piece of infrastructure to solve everything, what if thousands of appropriate interventions throughout a watershed collectively helped manage water?

A school harvesting rain.

A subdivision creating infiltration areas.

A farm retaining runoff.

An industrial estate improving groundwater recharge.

A community restoring a wetland.

A city protecting the open spaces that allow water to infiltrate.

Individually, some interventions may appear small.

Collectively, they can change how a landscape behaves.

From Rainwater Harvesting to Water Banking

Rainwater harvesting is often understood as putting a tank beside a building.

That is useful—but I believe the idea can become much bigger.

A landscape can harvest rain.

A farm can harvest rain.

A watershed can harvest rain.

And harvesting does not always mean putting water into a container.

Sometimes the best container may be healthy soil.

Sometimes it may be a pond.

Sometimes a restored wetland.

Sometimes an appropriately managed aquifer.

Sometimes it will be conventional storage.

The question is not:

Which technology do we want to install?

The better question is:

Where should the water go?

That answer should come from the landscape itself—from rainfall, topography, soils, geology, vegetation, land use, water demand and community needs.

The Five Rs of Water Savings

This is developing into what I think of as the Ecosensya Water Savings Approach.

It begins with five functions:

1. RECEIVE

Understand how much rain the landscape receives and where it comes from.

2. RETAIN

Slow water down and give it opportunities to remain within the landscape where appropriate.

3. RECHARGE

Allow water to return underground where soil, geology and aquifer conditions make recharge suitable.

4. REUSE

Use appropriately captured and stored water wisely for agriculture, communities and other suitable purposes.

5. REGENERATE

Use better water management to restore soil, vegetation, ecosystems, agricultural productivity and livelihoods.

Receive. Retain. Recharge. Reuse. Regenerate.

Water then becomes more than a commodity extracted from a pipe.

It becomes part of a living system.

Why Agriculture Matters

This thinking becomes particularly exciting when applied to agriculture.

A farm should not have to be only a place where we grow food.

Properly designed, agricultural land can potentially perform several functions simultaneously.

It can produce food.

It can retain rainfall.

It can improve infiltration.

It can help recharge groundwater where conditions allow.

It can build healthier soil.

It can support biodiversity.

It can store carbon.

And it can strengthen farmer resilience.

This leads to a relationship I believe deserves much greater attention:

Water → Soil → Food → Livelihood → Nature → Water

Regenerative agriculture needs water.

But regenerative land can also help manage water.

That is why I increasingly see water security and sustainable agriculture as parts of the same system.

My Questioning Approach

My path into environmental work has not been conventional.

I began with Industrial Engineering. I became an entrepreneur. I spent decades working with real estate and land. Later, I pursued

Environmental Management and continued studying permaculture, Nature-based Solutions and water management.

Each discipline taught me to see a different part of the same picture.

Engineering taught me to understand systems.

Entrepreneurship taught me to ask whether an idea can actually work.

Real estate taught me to understand land, value and human decision-making.

Environmental management taught me to examine the relationships among people, development and ecosystems.

Permaculture and Nature-based Solutions taught me to pay closer attention to how nature already performs many of the functions we are trying to engineer.

Water connected them all.

My professional journey has therefore made me comfortable asking questions—even questions that initially sound too simple.

At Ecosensya, I call this the Questioning Approach.

Before asking:

What should we build?

I want us to ask:

Why is this happening?

What changed?

How does the whole system work?

What is nature already trying to do?

What happens if we work with it instead of against it?

And increasingly:

Where does the rain go?

A Water-Positive Philippines

My vision for Ecosensya is becoming clearer.

I want us to help demonstrate what a Water-Positive Landscape can look like.

Imagine farms, schools, subdivisions, industrial estates, communities and cities understanding their own Water Savings Accounts.

How much rain do we receive?

How much water do we consume?

How much infiltrates?

How much runs off?

How much should remain for rivers and ecosystems?

How much could we responsibly retain?

How much groundwater are we withdrawing?

How much are we helping nature put back?

Those questions could change how we think about land development.

Perhaps someday, we will evaluate land not only by how many buildings we can put on it or how much agricultural produce it generates.

Perhaps we will also ask:

How well does this land manage water?

That would represent a profound change in how we value landscapes.

Start With the Next Rain

A Water-Positive Philippines will not begin with one enormous project.

It can begin with millions of smaller decisions.

A household can collect rainwater for appropriate non-potable uses.

A school can understand where rain falling on its roof goes.

A farmer can look for opportunities to retain water and improve soil moisture.

A property developer can design more space for infiltration.

A business can examine its water balance.

An LGU can begin mapping where rainfall could safely be retained and where groundwater recharge needs protection.

And every Filipino can begin with one simple question the next time rain starts falling:

Where does the rain go?

Then ask:

How much can we responsibly save?

And finally:

What can that saved water make possible?

For me, these are no longer simply questions about rainwater harvesting.

They are questions about the kind of country we want to build.

A country that does not see rain only as something to drain away.

A country that recognizes water as natural capital.

A country that restores the ability of its landscapes to hold water.

A country that prepares for drought while the rain is still falling.

Bank the Rain.

Build Water Savings. Restore Landscapes. Create a Water-Positive Philippines.

Antonina Lourdes “Queenie” E. Cunanan is Co-Founder and President of Ecosensya Solutions for Environmental Sustainability, Inc. Her work focuses on decentralized Nature-based Solutions, water security, climate resilience and the relationships among water, land and communities.