Pink Salmon Elwha Dam
Pink salmon, blocked from migrating further upstream, wait below the now removed Elwha Dam.

The folks behind the now award-winning documentary, DamNation, are asking more people to sign a petition calling on President Obama to begin removing obsolete dams throughout the US. The petition's initial target is four dams on the lower Snake River in Washington state.

According to the petition, "Snake River salmon and steelhead once thrived, with up to 30 million wild fish entering the mouth of the Columbia River every year. Now, every Snake River salmon stock is on the endangered species list or extinct."

The four dams, which include the Ice Harbor Dam, Lower Monumental Dam, Little Goose Dam and Lower Granite Dam, are widely recognized to be outdated and doers of far more harm than good. According to DamNation's creators, these "federally operated dams cost taxpayers millions every year, degrade water quality and impede salmon migration to and from the healthiest habitat remaining in the lower 48 states, while providing no flood control and little irrigation."

Since it began screening earlier this year, DamNation has received many accolades, including the Audience Choice Award at the 2014 SXSW film festival. The film -- from celebrated documentary filmmakers Ben Knight and Travel Rummel -- was financed by Patagonia, whose founder Yvon Chouinard is a ardent supporter of dam removal.

Chouinard has stated that "from an early age we are taught that we are responsible for cleaning up our own mess. But this lesson also applies to our home planet. When we despoil a place with toxic waste, change our climate with fossil fuels or build a destructive and soon-to-be useless dam, we have the responsibility to clean it up and make it all whole and natural again. Time and again, I’ve witnessed how removing an unnecessary dam is the responsible, and eventually celebrated, choice."

Sign the petition, learn more about the film or watch the trailer below.