Thursday, 16 May 2019

First global assessment of the ecological health of the world's "wild" rivers has found only about one third of the longest rivers are still free-flowing


As the Queensland flood waters finally make it down the Dimantina and Georgina rivers and Cooper's Creek and spread out over the Eyre Basin and into Kati Thanda-Lake Eyre, it is well to remember three things.

The first is that; The Lake Eyre Basin is one of the largest and most pristine desert river systems on the planet, supporting 60,000 people and a wealth of wildlife.

The second is the fact that the Morrison Government has a stated policy to dam and divert more water from Australia's river systems if it is re-elected. 

The third is that water sustainability into the future is dependent on wild rivers running free.

ABC Radio,“RN”, 9 May 2019:

The first global assessment of the ecological health of the world's "wild" rivers has found only about one third of the longest rivers are still free-flowing.

The report warns the disruption is harming ecosystems, with 3,700 new large dams either under construction, or planned.


Nature, 8 May 2019:

Gill,Gunter et al, (2019) Mapping the world’s free-flowing rivers

ABSTRACT

Free-flowing rivers (FFRs) support diverse, complex and dynamic ecosystems globally, providing important societal and economic services. Infrastructure development threatens the ecosystem processes, biodiversity and services that these rivers support. Here we assess the connectivity status of 12 million kilometres of rivers globally and identify those that remain free-flowing in their entire length. Only 37 per cent of rivers longer than 1,000 kilometres remain free-flowing over their entire length and 23 per cent flow uninterrupted to the ocean. Very long FFRs are largely restricted to remote regions of the Arctic and of the Amazon and Congo basins. In densely populated areas only few very long rivers remain free-flowing, such as the Irrawaddy and Salween. Dams and reservoirs and their up- and downstream propagation of fragmentation and flow regulation are the leading contributors to the loss of river connectivity. By applying a new method to quantify riverine connectivity and map FFRs, we provide a foundation for concerted global and national strategies to maintain or restore them.

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