"World's Top Ten Rivers at Risk"

Perhaps there was a time when that was true, but no longer. Even the greatest of the world’s rivers can no longer be assured of reaching the sea unhindered. These days the Rio Grande/Rio Bravo River, on the border of the U.S. and Mexico, often fails to reach the Gulf of Mexico, its strength sapped by dams and irrigation works diverting water to farmers’ fields and city water supplies. The Indus, the Nile, the Murray-Darling, the Colorado, these are but a few of the once mighty rivers that now struggle to touch the ocean.

In fact, water extraction is only one of the daunting challenges that a river faces as it makes its way to its terminus. Dams and channelization destroy habitats, cut rivers off from their floodplains, and alter the natural ebb and fl ow on which a river’s plants and animals depend. Invasive species crowd rivers’ banks, drive out their native fishes, and choke their courses.

Pollution fouls their waters, sometimes turning life-giving rivers into threats to human health. And climate change threatens to alter all the rules that rivers have lived by for thousands of years.

Why is this important? Because endangered rivers threaten the livelihoods of people. Rivers basins are the way nature gathers and delivers water for human use. These ecosystems provide electricity generation, transport, recreation and tourism, and valuable but often unaccounted fl ood and drought regulation, sediment and nutrient retention, and habitat for diverse fauna and flora. Freshwater biodiversity is an important source of food, income, and livelihood, particularly to rural communities in developing countries. Studies have estimated the economic value of river basins in the billions of dollars (Schuyt 2005)