Tag Archives: Dams

Dams – Cutting off our Beach Sand; By Gary Griggs

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San Clemente Dam, Carmel River, California. Photograph by: © 2007 Gary Griggs

By © Gary Griggs, Author of “Our Ocean Backyard- Collected Essays”

In addition to providing most of California’s drinking water, the state’s rivers and streams also provide about 75% of our beach sand. In order to provide water for agriculture, industry and homes, as well as flood control, recreation and hydroelectric power, the state’s rivers were extensively dammed throughout the last century.

There are now more than 500 dams impounding rivers and streams that drain directly into the Pacific along our coastline. Since the first one was built in 1866, an average of 3.5 dams have been built each year ever since. In addition to storing water, the reservoirs behind each of these 500 barriers also trap sand that used to be carried to the shoreline.

Dams now withhold sediment from about 16,000 square miles of the state’s coastal watersheds and have reduced the flow of sand by 25%, or about 3.6 million cubic yards each year. That’s 360,000 dump truck loads annually. The total amount of beach sand now trapped behind all of California’s coastal dams totals about 200 million cubic yards, or a line of dump trucks bumper to bumper stretching completely around the world nearly four times.

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These reductions vary regionally: in northern California, there are still a number of relatively undisturbed rivers, the Smith and Eel rivers, for example, and sand supply has only been reduced by 5%; in central California, 31% of the sand flow has been eliminated by dams; and in southern California, hundreds of water supply lakes, reservoirs, flood control projects, and debris basins have reduced sand supply to the coast by about 50%.

The long-term sustainability of California’s beaches depends primarily on the periodic delivery of sand and gravel from coastal rivers and streams. Sand supply to the state’s beaches wasn’t a con- cern, however, when most of California’s streams were dammed.

The benefits of more water, flood control, recreation, and hydroelec- tric power in some cases, were compelling to farmers, fishermen, and politicians through much of the 20th century. Over the past 25 or so years, however, the side effects of dams, including loss of salmon migration and spawning grounds, as well as beach sand impoundment, have become more and more evident.

The construction of new dams has come to a halt in California and in other states as well, and is actually now going into reverse. A number of dams that formed barriers to fish migration and that were completely full of sediment have been taken down across the country and others are being studied for removal.

In California, San Clemente Dam on the Carmel River, Gibralter Dam on the Santa Ynez River, Matilija Dam on the Ventura River, and Rindge Dam on Malibu Creek are now completely full of sediment and no longer serve any purpose. Additionally, because they were built many decades ago, their seismic safety is now a concern. Combined these 4 dams have trapped 2.8 million dump truck loads of sand that can end up on the downstream beaches. Google “dam removal” to see some of the dam removal projects that have already been accomplished.

We can do the same in California and get the sand from these dysfunctional reservoirs onto the beaches where it belongs.

Learn More: “Our Ocean Backyard – Collected Essays”; a Book by Gary Griggs
For the three billion people on Earth who live in coastal regions, the ocean is figuratively, if not literally, “our backyard.” The oceans enrich our lives in countless ways, but our interactions with them have not always been positive. Gary Griggs, a coastal geologist and oceanographer, is known for making science understandable, enjoyable, and accessible to non-scientists, was asked to write a bi-weekly column, “Our Ocean Backyard” for the Santa Cruz Sentinel…

Sediment Trapped Behind Dams Makes Them ‘Hot Spots’ for Greenhouse Gas Emissions
The large reservoirs of water behind the world’s 50,000 large dams are a known source of methane. Methane has a warming effect 25 times more powerful than carbon dioxide. That knowledge led to questions about hydroelectric power’s image as a green and nonpolluting energy source…

DamNation; a Documentary That’s Testing the Waters of Corporate Social Responsibility; From Felt Soul Media
DamNation is a feature documentary, shown this week at SXSW in Austin, Tx. DamNation’s majestic cinematography and unexpected discoveries move through rivers and landscapes altered by dams, but also through a metamorphosis in values, from conquest of the natural world to knowing ourselves as part of nature…

Elwha, The Grand Experiment (11-12-2012)

Tracking Sediments’ Fate In Largest-Ever Dam Removal
Scientists tracking the aftermath of the largest dam removal in U.S. history say the dismantling of a dam in northwestern Washington state has unleashed about 34 million cubic yards of sediment and debris that built up for more than a century…

Let’s Talk About Sand: “Sand Wars” Film Director Denis Delestrac, At TEDxBarcelona

Protect the World’s Deltas

primer
Batik on silk by © Mary Edna Fraser

Excerpts;

The rich delta ecosystem and the services it provides, storm protection, nutrient and pollution removal and carbon storage, are being destroyed. Worldwide deltas are on course to drown, starved of sediment by dams and dikes, and fragmented by economic development.

Rising seas compound the sediment crisis…

Read Full Article, Nature

Life-Giving Deltas Starved by Dams, y Peter Bosshard, Policy Director, International Rivers (05-24-2014)
At a time when coastal areas are already battered by climate change, life-giving deltas are being sacrificed to dam building…

Relief for a Parched Delta, The New York Times (04-17-2013)
Thanks to dams that throttled the Colorado and diverted its water to fuel the rise of the American West, the river has effectively ended at the Mexican border. The Colorado delta, once a lush network of freshwater and marine wetlands and meandering river channels and a haven for fish, migrating birds and other wildlife, is largely a parched wasteland…

DamNation; a Documentary That’s Testing the Waters of Corporate Social Responsibility; From Felt Soul Media
DamNation is a feature documentary, shown this week at SXSW in Austin, Tx. DamNation’s majestic cinematography and unexpected discoveries move through rivers and landscapes altered by dams, but also through a metamorphosis in values, from conquest of the natural world to knowing ourselves as part of nature…

World’s Largest Dam Removal Unleashes U.S. River, NBC news, (08-27-2014)
River Reborn: Elwha Flows Wild and Free Once Again..

Elwha, The Grand Experiment (11-12-2012)

A UN Report On Sand Mining: “Sand, Rarer Than One Thinks”
The United Nations, under its environmental programe and agency UNEP, released a report about sand mining, entitled: “Sand, rarer than one thinks”

Let’s Talk About Sand: Denis Delestrac At TEDxBarcelona
Denis Delestrac latest feature documentary, “Sand Wars” is an epic eco-thriller that takes the audience around the globe to unveil a new gold rush and a disturbing fact: we are running out of sand! In this TEDxBarcelona talk, he explains us where sand comes from and where it ends up…

Sand Wars, An Investigation Documentary, By Denis Delestrac

Nile Delta Desert Islands
Nile Delta Desert Islands, batik on silk by © Mary Edna Fraser
52” x 36”, 1999

EU Takes Legal Action Against Controversial French Dam

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Barrage de Bimont, Provence-Alpes-Côte d’Azur., France. Photo source: ©© Meriol Lehmann

Excerpts;

The European commission has sent France a final notice to explain how it can reconcile EU environmental law with a proposed dam project that sparked riots, which claimed a protester’s life last month…

Read Full Article, Guardian UK

As Small Hydropower Expands, So Does Caution on Its Impacts, Yale E 360 (08-06-2014)

Small Dams On Chinese River Harm Environment More Than Expected, study finds, NSF (05-30-2013)

Hydropower: Huge Source of Methane Emissions

dam-emissions-petit-saut-reservoir
Dire Consequences of Dam Reservoir Emissions, Petit Saut Reservoir, French Guiana. A growing number of scientific studies indicate that reservoirs, especially in the tropics, are a significant source of global greenhouse gas pollution. The “fuel” for these emissions is the rotting of organic matter from the vegetation and soils flooded when the reservoir is first filled. The carbon in the plankton and plants that live and die in the reservoir, the detritus washed down from the watershed above, and the seasonal flooding of plants along the reservoir fringes, ensure that emissions continue for the lifetime of the reservoir. Captions and Photo source: ©© Frédéric Guérin / International Rivers

Excerpts;

Reservoirs and hydropower are often thought of as climate friendly because they don’t burn fossil fuels to produce electricity. But what if reservoirs that store water and produce electricity were among some of the world’s largest contributors of greenhouse gas emissions?

Read Full Article, Climate Central

Sediment Trapped Behind Dams Makes Them ‘Hot Spots’ for Greenhouse Gas Emissions, Science Daily (08-01-2013)
The large reservoirs of water behind the world’s 50,000 large dams are a known source of methane. Methane has a warming effect 25 times more powerful than carbon dioxide. That knowledge led to questions about hydroelectric power’s image as a green and nonpolluting energy source…

Tropical Dams: Ebullition Causes Methane Emissions Considerably More Powerful than CO2, CNRS via ALphagalileo (09-14-2014)

Large Dams Just Aren’t Worth the Cost, The New York Times (10-25-2014)

Small Dams On Chinese River Harm Environment More Than Expected, study finds, NSF (05-30-2013)

Controversial dam projects – in pictures, The Guardian UK
A look is taken at some of the world’s most contentious dam projects, from the Three Gorges in China to Brazil’s Belo Monte dam.

DamNation; a Documentary That’s Testing the Waters of Corporate Social Responsibility; From Felt Soul Media
DamNation is a feature documentary, shown this week at SXSW in Austin, Tx. DamNation’s majestic cinematography and unexpected discoveries move through rivers and landscapes altered by dams, but also through a metamorphosis in values, from conquest of the natural world to knowing ourselves as part of nature…

Elwha, The Grand Experiment (11-12-2012)

Large Dams Just Aren’t Worth the Cost

pak-ben-dam-laos
The Pak Beng dam, to be located north of Luang Prabang in northwestern Laos’ Oudomxay province. Pak Beng Dam, would create a stagnant reservoir, raise water levels behind the dam 40 feet, and back up the river near Huay Luk, forcing the resettlement of communities.
With a massive dam under construction in Laos and other dams on the way, the Mekong River is facing a wave of hydroelectric projects that could profoundly alter the river’s ecology and disrupt the food supplies of millions of people in Southeast Asia. Captions: Yale E 360. Photo source: International Rivers

Excerpts;

Thayer Scudder, an emeritus anthropology professor at the California Institute of Technology and the world’s leading authority on the impact of dams on poor people, describes his disillusionment with dams…

Large Dams Just Aren’t Worth the Cost, The New York Times

What Is A Large Dam? Questions and Answers About Large Dams by International Rivers
A large dam is defined by the dam industry as one higher than 15 metres (taller than a four-story building). There are more than 40,000 large dams worldwide. There are more than 300 major dams – giants which meet one of a number of criteria on height (at least 150 metres), dam volume and reservoir volume…

Read Full Article: “World’s Largest Dam Removal Unleashes U.S. River After Century of Electric Production,” National Geographic
The blasts will destroy the last 30 feet of the 210-foot-high dam and will signal the culmination of the largest dam-removal project in the world.
In Asia, Africa, and South America, large hydroelectric dams are still being built, as they once were in the United States, to power economic development, with the added argument now that the electricity they provide is free of greenhouse gas emissions. But while the U.S. still benefits from the large dams it built in the 20th century, there’s a growing recognition that in some cases, at least, dambuilding went too far—and the Elwha River is a symbol of that…

Elwha, The Grand Experiment (11-12-2012)

Controversial dam projects – in pictures, The Guardian UK
A look is taken at some of the world’s most contentious dam projects, from the Three Gorges in China to Brazil’s Belo Monte dam.

Sediment Trapped Behind Dams Makes Them ‘Hot Spots’ for Greenhouse Gas Emissions
The large reservoirs of water behind the world’s 50,000 large dams are a known source of methane. Methane has a warming effect 25 times more powerful than carbon dioxide. That knowledge led to questions about hydroelectric power’s image as a green and nonpolluting energy source…

Small Dams On Chinese River Harm Environment More Than Expected, study finds, NSF (05-30-2013)

DamNation; a Documentary That’s Testing the Waters of Corporate Social Responsibility; From Felt Soul Media
DamNation is a feature documentary, shown this week at SXSW in Austin, Tx. DamNation’s majestic cinematography and unexpected discoveries move through rivers and landscapes altered by dams, but also through a metamorphosis in values, from conquest of the natural world to knowing ourselves as part of nature…

Timelapse Of The Removal Of Glines Canyon Dam on the Elwha River, Video


Learn More About: Elwha River Restoration, On Facebook

World’s Largest Dam Removal Unleashes U.S. River
A construction crew on Tuesday detonated a large charge of dynamite, destroying the last remaining portion of Glines Canyon Dam and hastening the restoration of the Elwha River in the far reaches of the Pacific Northwest. Part of the largest dam-removal project in the nation, the $325 million undertaking represents the beginning of a new era for the river…

A Flood of Energy Projects Clash with Mexican Communities

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Cascada de Las Monjas, Xico, Veracruz, Mexico. Photo source: ©© Sergio Lubezky

Excerpts;

Since January, villagers and townspeople near the Los Pescados river in southeast Mexico have been blocking the construction of a dam, part of a multi-purpose project to supply potable water to Xalapa, the capital of the state of Veracruz.

The dam has a planned capacity of 130 million cubic metres, a reservoir surface area of 4.13 square kilometres and a cost of over 400 million dollars. It is one of more than a hundred dams planned by federal and state governments, which are causing conflict with local communities…

Read Full Article, IPS News

Tropical Dams: Ebullition Causes Methane Emissions Considerably More Powerful than CO2, CNRS via ALphagalileo (09-14-2014)
For the first time, methane emissions by ebullition from tropical reservoirs have been accurately quantified…

Sediment Trapped Behind Dams Makes Them ‘Hot Spots’ for Greenhouse Gas Emissions, Science Daily (08-01-2013)
The large reservoirs of water behind the world’s 50,000 large dams are a known source of methane. Methane has a warming effect 25 times more powerful than carbon dioxide. That knowledge led to questions about hydroelectric power’s image as a green and nonpolluting energy source…

Tropical Dams: Ebullition Causes Methane Emissions Considerably More Powerful than CO2

dam-emissions-petit-saut-reservoir
Dire Consequences of Dam Reservoir Emissions, Petit Saut Reservoir, French Guiana. A growing number of scientific studies indicate that reservoirs, especially in the tropics, are a significant source of global greenhouse gas pollution. The “fuel” for these emissions is the rotting of organic matter from the vegetation and soils flooded when the reservoir is first filled. The carbon in the plankton and plants that live and die in the reservoir, the detritus washed down from the watershed above, and the seasonal flooding of plants along the reservoir fringes, ensure that emissions continue for the lifetime of the reservoir. Captions and Photo source: ©© Frédéric Guérin / International Rivers

Excerpts;

For the past ten years, it has been known that hydroelectric reservoirs in tropical regions are an important source of methane (CH4), a greenhouse gas that is considerably more powerful than carbon dioxide. Methane is produced by bacteria that decompose organic matter in the soils and vegetation flooded when the reservoir is filled. In tropical regions, these reservoirs probably release between 1% and 18% of anthropogenic methane into the atmosphere.

For the first time, methane emissions by ebullition from tropical reservoirs have been accurately quantified…

Read Full Article, CNRS via ALphagalileo

Sediment Trapped Behind Dams Makes Them ‘Hot Spots’ for Greenhouse Gas Emissions, Science Daily (08-01-2013)
The large reservoirs of water behind the world’s 50,000 large dams are a known source of methane. Methane has a warming effect 25 times more powerful than carbon dioxide. That knowledge led to questions about hydroelectric power’s image as a green and nonpolluting energy source…

Nam Theun 2 Dam, Laos; International Rivers

Experiencing The Rebirth Of A River

elwha
©Photo courtesy of Dylan Tomine

Excerpts;

“The first thing we noticed was the amazing clarity of the water. Opponents of the dam removal predicted the river would be constantly dirty with sediment for years to come, and yet, even just days after blowing the last of the upper dam, we had at least eight feet of gorgeous, blue-green-tinted visibility…”

Read Full Article, By Dylan Tomine

World’s Largest Dam Removal Unleashes U.S. River (08-27-2014)
A construction crew detonated a large charge of dynamite, destroying the last remaining portion of Glines Canyon Dam and hastening the restoration of the Elwha River in the far reaches of the Pacific Northwest. Part of the largest dam-removal project in the nation, the $325 million undertaking represents the beginning of a new era for the river…

“River Reborn: Elwha Flows Wild and Free Once Again,” NBC News

Elwha, The Grand Experiment (11-12-2012)

DamNation; a Documentary That’s Testing the Waters of Corporate Social Responsibility; From Felt Soul Media
DamNation is a feature documentary, shown this week at SXSW in Austin, Tx. DamNation’s majestic cinematography and unexpected discoveries move through rivers and landscapes altered by dams, but also through a metamorphosis in values, from conquest of the natural world to knowing ourselves as part of nature…

Controversial dam projects – in pictures, The Guardian UK
A look is taken at some of the world’s most contentious dam projects, from the Three Gorges in China to Brazil’s Belo Monte dam.