WWF’s “A Deep Dive Into Freshwater” supplement to the “Living Planet Report 2020” underlines the importance of river connectivity, not only for freshwater species, but for our health too.

Freshwater species are declining at a staggering rate, faster than terrestrial ones. This change is being driven by our increasing freshwater consumption, 1% per year, “in line with a growing population and the increasing demand for thirsty products that comes with rising wealth”. 

In other words, our energy generation, food and fibre production (agriculture, livestock and plantations), urban and infrastructure development, and water supply have a great impact, greater than we might think. This translates into how we use dams and hydropower, how we extract raw materials – wood, sand, how we harvest species and how we farm. Crop and livestock production alone amount for three quarters of freshwater withdrawals.

The environmental impact is being described by many studies and reports. “Most of the world’s longest rivers have been dammed or otherwise altered; only a third of the world’s 242 longest rivers, more than 1,000km long, remain free-flowing”, usually in very remote areas.

All this despite the fact that  “many freshwater species depend on connectivity between upstream and downstream river reaches, or between river channels and floodplain habitats, for their migration and reproduction. Dams and weirs fragment longitudinal (upstream-to-downstream) connectivity and, through flow alterations, also affect lateral (river-to-floodplain), vertical (surface-to-groundwater) and temporal (season-to-season) connectivity. Coherent planning for energy and water, including strategic siting of new infrastructure and due consideration of alternative options, can balance connectivity maintenance with hydropower generation or
water storage.”

But new research shows that “the destruction of these natural systems can impair their ability
to support human health, while presenting new health threats.
For example, the construction of dams has put nearly 400 million people at greater risk of schistosomiasis, a parasitic disease carried by snails. Dams disrupt the ecology of snail-eating river prawns, increasing snail numbers and the risk of human infection. One-third to a half of humans at risk of schistosomiasis could benefit from the restoration of rivers to re-establish prawn populations.“

In 2019 an international group of freshwater ecosystem experts gathered to define priorities for bending the curve of freshwater biodiversity loss.

The Emergency Recovery Plan for Global Freshwater Biodiversity includes 6 points:

1  Allowing rivers to flow more naturally
2  Reducing pollution
3  Protecting critical wetland habitats
4  Ending overfishing and unsustainable sand mining
5  Controlling invasive species
6  Safeguarding and restoring connectivity