Vast amounts of river-borne sediment are trapped behind the world’s large dams, depriving areas downstream of material that is badly needed to build up the marshes and wetlands that act as a buffer against rising seas.

In September 2011, after 20 years of planning, workers began dismantling the Elwha and Glines dams on the Elwha River in northwestern Washington state. At the time, it was the largest dam removal project in U.S. history, and it took nearly three years for both barriers to be dismantled and for the river to once again flow freely. 

Over the course of their nearly century-long lives, the two dams collected more than 24 million cubic yards of sediment behind them, enough to fill the Seattle Seahawks football stadium eight times. And since their removal, the Elwha has taken back the trapped sediment and distributed it downstream, causing the riverine ecosystem to be rebuilt and transformed. Massive quantities of silt, sand, and gravel have been carried to the coast, resurrecting a wetlands ecosystem long deprived of sediment.

Read more ...

Europe’s wild snakes could face a growing threat from a fungal skin disease that has contributed to wild snake deaths in North America, according to an international collaborative study, led by conservation charity Zoological Society of London alongside partners including the U.S. Geological Survey. The new study is published in the journal Scientific Reports.

Read more ...

The quality of the air in California may be improving, but it's still dire.

That's according to the American Lung Association's recent "State of the Air 2017" report, which labeled the state and region a leader in air pollution, with the highest ozone levels.

The annual study ranks the cleanest and most polluted areas in the country by grading counties in the U.S. based on harmful recorded levels of ozone (smog) and particle pollution. The 2017 report used data collected from 2013 to 2015.

Read more ...

More Articles ...

Subcategories