Nil-by-Mouth

Tidal River Litter Corral

A woman swims with a manta ray in a sea of plastic off the coast of Bali. This image was instrumental in fostering the Long Future Foundation to consider ways to prevent plastic entering the ocean.

A Global Problem and Our Solution

Each year, 8 million tonnes of plastics enters the oceans. Most of this comes from the land, via rivers.

The Long Future Foundation has an aspiration that no plastic should depart a river mouth, and that no plastic should be consumed by marine wildlife.

We call this vision Nil-by-Mouth.

To help make this vision real, Long Future has developed a number of innovations (e.g. the Cleanership) and a new killer-app in the war against marine plastics, simply called the Corral.

The Corral is a new technology that could help prevent millions of tonnes of plastic entering the world ocean, every year.

It does this by simply intercepting the plastic litter from rivers, as it drifts on the incoming and outgoing tides.

As nearly all rivers are tidal in their lower reaches, the Corral has application world-wide.

The images below show a representation of a Corral as it would look in a proposed demonstration site in St Lucia, Brisbane.

This particular design is the first in what could come to be many different versions, each tailored to their locations.

The key innovation in the Corral is the Reciprocal One-way Gates that allow litter into the Corral, but prevent if from leaving, thus arresting it on its journey to th sea.

Long Future's vision is that marine wildlife should never be exposed to plastics. We call this vision: Nil by Mouth.

The Tidal River Litter Corral, as it would look.

System elements of the Tidal River Litter Corral.

The anchor points of the Tidal River Litter Corral.

Diagram of the Corral One-Way Gates.

How it works.

As the litter drifts in the river, it strikes the containment boom, and is diverted towards the upstream one-way gate.

The upstream one-way gate is pushed open by force of the moving water, however, the reciprocal one-way gate (downstream) is kept closed by the flowing water.

When the litter enters the Corral it cannot escape, until it is manuall removed by human intervention, or mechanical device.

When the tide goes slack, both gates close due to their buoyancy, and when the tide begins to run again, the reciprocal gate opens.

In this way, litter is collected on both the incoming and outgoing tide.