0. Opening
This is not a story about something we need to do right now.
However, it may be a story about an idea
that Tokyo could feel the need for in the future.
From 2025 to 2026,
the Kanto region experienced a clear tendency toward water shortages,
starting already in winter.
This was an unusual situation,
but not one without precedent.
Using that situation as a starting point,
today I’d like to share a thought process:
How might the snow from heavy snowfall regions
be treated as a potential water source for Tokyo?
1. The First Idea I Considered
At first, I thought about it like this.
In regions such as Niigata,
millions of tons of snow accumulate every year.
What if that snow were transported to Tokyo
by ship or by rail?
Could it become part of a drought mitigation strategy?
In fact, using ships,
it is technically possible to transport
around 3,000 tons of snow at once.
2. What the Numbers Reveal
Three thousand tons of snow
becomes about 3,000 cubic meters of water.
At first glance, that sounds like a large amount.
But Tokyo’s total daily water consumption
is roughly five to six million cubic meters.
Which means—
3,000 tons of snow corresponds to
only about 50 seconds’ worth of water usage
for Tokyo as a whole.
Even if it were added to a dam,
the change in water level would be almost invisible.
At that point, it becomes clear that
this approach doesn’t work
if we think of it as a water source for all of Tokyo.
3. The Shift in Perspective
So I reconsidered.
If the amount isn’t sufficient,
then perhaps the solution is
to limit where it is used.
It doesn’t work because we are trying
to apply it to the entire city.
But what if we focused only on
Tokyo’s waterfront areas?
4. How the Structure Changes When Limited to the Waterfront
The waterfront areas of Tokyo have several characteristics:
A high concentration of population and business activity
High water consumption
And, importantly, direct access to ports
If, during a drought,
only the waterfront districts could switch their water source
to water derived from snow
brought in from heavy snowfall regions—
Even 3,000 tons of water could
support part of that area’s demand
for several days.
The key point is this:
If a water treatment plant is located near the port,
and connected directly to the existing water supply network,
then the waterfront’s water demand
does not need to rely on inland dams.
As a result,
water intake from inland sources can be reduced.
In effect,
this functions as a de facto water intake restriction,
without imposing restrictions across the entire city.
5. A System That Works
Because
We Don’t Transport Water Inland
Here, another realization emerges.
There is no need to transport water inland.
That means no long-distance pipelines,
no tunnels through mountains,
and no large-scale pumping infrastructure.
Snow is transported by ship to Tokyo Bay,
melted and treated near the waterfront,
and then supplied directly
to the waterfront water network.
It operates only during drought periods,
as a supplementary water source limited to the bay area.
Under this structure,
the idea becomes far more realistic.
6. Snow Is Not a “Nuisance” — It Becomes a Resource
For a long time,
snow removal in heavy snowfall regions
has been treated as a burden—
something dangerous, costly,
and necessary to eliminate.
But that snow, in reality,
can become a clear resource
if it can be transported
to regions suffering from water shortages.
With a shift in perspective,
snow moves from being:
a burden
a cost
a hazard
to becoming
a potential water source that supports urban life.
7. A Realistic Way to Fund the System
Now comes the question of funding.
This system does not require
immediate deployment using Tokyo’s general budget.
A realistic mechanism already exists:
purpose-designated hometown tax donations.
Municipalities in heavy snowfall regions could designate donations for:
Snow removal and roof clearing
Snow collection and transport to ports
Maritime transport to Tokyo, only when necessary
In years when snow is not transported,
the donated funds remain available
for local use at the municipality’s discretion.
From Tokyo’s perspective,
tax revenue is already flowing out through this system.
But in this case,
that same flow of funds
would also help reduce Tokyo’s own drought risk.
Both Tokyo and regions outside Tokyo
end up benefiting from the same mechanism.
8. Why Tokyo Might Be Willing to Act
Tokyo has the largest budget
of any local government in Japan.
This gives it a high degree of flexibility
in funding urban infrastructure and public services.
What Tokyo most wants to avoid
is imposing water restrictions
across the entire city.
If the waterfront alone can switch water sources,
it creates room to protect inland water supplies.
That structural advantage
is what makes this idea feasible.
9. This Is Not About Immediate Necessity
To be clear,
this is not essential infrastructure today.
Winter droughts are still relatively rare.
However, even a one-degree rise in average temperature
significantly alters patterns of snowfall and rainfall.
In 2035, or 2040,
when Tokyo may feel the need
for a form of “water insurance,”
it would be meaningful
if this structure still exists
as one option worth considering.
10. Conclusion
This is not a story
about transporting massive amounts of snow.
It is a story
about choosing where snow is used.
Rather than forcing nature to move,
it involves slightly adjusting
the structure of the city.
This is a record of
one possible way of thinking
about future water resources.