Project B.I.G.

Bypass Ramp Installation Gift

The Nawa River is home to an important population of Japanese giant salamanders, but it is also heavily fragmented.

There are 53 artificial weirs in the Nawa River alone. These barriers divide the river and can prevent giant salamanders from moving upstream.

Project B.I.G. — Bypass Ramp Installation Gift — was created by Sustainable Daisen to change that.

The goal is permanent bypass ramps that allow Japanese giant salamanders to move around these barriers and reconnect sections of their habitat.

But Project B.I.G. is also about demonstrating something else: that people care enough about this extraordinary animal to make that happen.

How Project B.I.G. began

As our work in the Nawa River developed, the scale of the fragmentation problem became increasingly clear.

Bypass ramps offered a practical way of allowing Japanese giant salamanders to move around barriers without removing the weirs themselves.

We approached the authorities about the problem and the potential solution. Although both were understood, we were told that there was not enough public interest to provide funding.

That became the starting point for Project B.I.G.

If a lack of public interest was standing in the way, we wanted to demonstrate that the interest exists — not only in Japan, but around the world.

The idea behind the “Gift”

The concept is simple.

Individuals, businesses and organisations can provide the funding for a bypass ramp. The completed ramp is then gifted for installation on the river.

In this way, people anywhere in the world can make a direct and tangible contribution towards reconnecting Japanese giant salamander habitat in Daisen.

Rather than simply saying that people care about the future of this species, Project B.I.G. provides a way to demonstrate it.

Why bypass ramps?

Artificial barriers can prevent Japanese giant salamanders from moving upstream through the river.

A bypass ramp provides another route around a barrier, allowing a salamander to continue upstream rather than being stopped by the structure.

With 53 weirs in the Nawa River alone, this is not a problem that can be addressed overnight. The aim is to install permanent bypass ramps at important locations and progressively reconnect fragmented sections of the river.

Each permanent ramp represents another connection restored.

The first ramps

In August 2026, Project B.I.G. took an important step forward.

Working with Japanese giant salamander specialists, including Professor Naoki Takahashi, we installed temporary wooden bypass ramps in the Nawa River Basin.

These experimental structures are now being monitored as part of our continuing work in the river.

They are an important stage in the development of Project B.I.G., but they are not its final objective.

The goal: permanent bypass ramps

The ultimate goal of Project B.I.G. is permanent bypass ramps on the Nawa River.

Permanent structures would allow Japanese giant salamanders to move upstream past barriers and begin reconnecting habitat that has been fragmented for decades.

Our temporary ramps, field research and monitoring are all taking place alongside that larger ambition.

We want to move from temporary interventions to lasting changes in the river.

More than a salamander

The Japanese giant salamander is the focus of Project B.I.G., but reconnecting a river has significance beyond a single species.

Rivers are living systems. Fragmentation changes how animals move through them and separates habitats that were once connected.

By restoring connectivity for one of Japan's most remarkable freshwater animals, Project B.I.G. also draws attention to the wider condition of the rivers on which it depends.

For Sustainable Daisen, protecting the Japanese giant salamander means protecting the river itself.

International support for a local river

Project B.I.G. is rooted in a small river system in rural Tottori, but the interest in protecting the Japanese giant salamander extends far beyond Daisen.

That is an important part of the project.

We were told there was not enough public interest to fund bypass ramps. Project B.I.G. gives people in Japan and around the world an opportunity to show otherwise.

A contribution from another part of Japan — or another country entirely — can result in something physical here in Daisen: a permanent structure helping reconnect the habitat of a threatened species.

Gift a bypass ramp

Our target is approximately US$5,000 to fund a bypass ramp.

Individuals, businesses, schools, clubs and organisations can support Project B.I.G., either by funding a ramp or contributing towards the project.

Support goes directly towards turning the idea of a connected river into something physical.

The goal is simple: permanent bypass ramps, a more connected Nawa River, and a better future for its Japanese giant salamanders.

Project B.I.G. began because we were told there wasn't enough public interest.

We intend to show that there is.