06/03/2010 05:12 am ET | Updated May 25, 2011

Sold Down the River; Fishers Fight for Healthy Rivers

The fishers of the world are fighting mad. Rivers and the lakes they feed are drying up, partly due to climate change and drought, but also because large dams are holding back their waters.

These formerly self-sufficient people want their rivers back, and they're making noise about it around the world. Recent protests in Thailand, Kenya and California have focused attention on the ecological and social risks of dam-building and water diversions on the Mekong, Africa's Omo River, and the once-fishy rivers of northern California.

Dams don't just impact the people whose homes and farms are flooded out for the reservoir. They also do great harm to downstream ecosystems, and the people who depend on them. These people are rarely counted in the official census of dam-affected people when a big dam is being built. In some cases, the impacts can be severe for hundreds of miles downstream, often affecting more people than the reservoir itself. (For a primer on dam impacts, view "We All Live Downstream.")

Some rivers have gone dry below dams for miles - the Colorado in the U.S. and the Yellow in China are just two examples of major rivers that no longer reach the sea because their waters have been dammed and diverted. Central California's San Joaquin River was another such example, but in this case there's a happy ending in the works: a major effort is underway to restore the river and its once-prized salmon runs. Just last week, once-dry sections below Friant Dam were flowing with water for the first time in decades.

While that's very encouraging to salmon watchers and river lovers in the Golden State, this global cadre of protesting fishers is saying "first, do no harm"--and trying to prevent their fisheries from going belly-up in the first place.

Here's a rundown of recent highlights from the rising tide of downstream communities speaking out for rivers:

Ethiopia is building a huge dam on the Omo River, with little thought to how it will impact half a million river-dependent people living downstream. Particularly outspoken have been Kenyan farmers and fishers who live around Lake Turkana, which could dry up if the dam is completed. (Watch a locally produced video on the risks to the world's largest desert lake.)

This troublesome project has attracted the attention of a broad coalition of environmental and human rights groups, who are helping to amplify the voices of local people. The coalition recently launched a petition to stop the dam. (Sign the petition here.)

Across the globe, the mighty Mekong, which supports the world's largest inland fishery, is in big trouble from one of the worst droughts in 50 years. Many local people suspect dams are playing a role in worsening the situation.

The Hindu reports that the United Nations Environment Programme warns of a "considerable threat" to the Mekong downstream of dams being built in China, but notes, "China says the course and flow of the Mekong have been unaffected by its projects."

An editorial in the Bangkok Post points out that too little information on river flows is coming out of China, which in addition to existing dams, is now building the world's tallest arch dam on the Mekong. This huge dam, the authors write, will have "a reservoir capacity of at least 15 cubic kilometers of water, which is approximately five times larger than the combined storage of the three existing [Mekong] dams and will take 10 years to fill. Therefore, whilst less rainfall is undoubtedly a key factor in the current drought, whether the Xiaowan dam's reservoir filling over the last rainy season has compounded the drought's severity remains an open and urgent question."

A typical argument from dam proponents is that a river can be made more predictable - new and improved! - from damming, because human control will even out Mother Nature's sometimes capricious approach to river flows. The New York Times reports that Jeremy Bird, Chief Executive Officer of the Mekong River Commission, "said he believed that more dams in China could even out the Mekong's seasonal variations by storing water when it was plentiful and releasing it when scarce."

But local activist Pianporn Deetes says that argument is not persuasive. She told the Times, "We don't need more water in the dry season, and we don't need less in the wet season," she said. "We would like to see the water as it is."

Finally, in my home state of California, "enraged salmon fishermen held an emotional call-to-arms in San Francisco Thursday, vowing to fight to save the vanishing Chinook salmon," the San Francisco Chronicle reports.

Two years of canceled salmon seasons have cost California $2.8 billion in revenue and at least 23,000 jobs, the fishermen say. California has a highly engineered system of dams, aqueducts, pumps and other fish-killing technology that has led to a steady decline in biodiversity, most noticeably in fisheries.

The Klamath River on the California-Oregon border is another where salmon runs have been terribly depleted from dams. The good news an agreement to remove the dams has been reached. The bad news is the project won't start till 2020.

Let's hope the salmon and the fisherfolk can hold out till then. Meanwhile, the struggle continues.