* Environmental groups worry about spills, forest damage
* 275 protesters arrested so far at the White House
* Pipeline to run from Alberta to Texas
By Timothy Gardner
WASHINGTON, Aug 24 (Reuters) - Ten U.S. environmental groups came out in support of hundreds of protesters arrested at the White House since Saturday for opposing a proposed $7 billion pipeline that would greatly expand imports of crude extracted from Canadian oil sands.
The pipeline and processing of the oil, they claim, can potentially spill oil over a vast source of underground water, release large amounts of greenhouse gases, and damage Canadian forests.
“We want to let you know that there is not an inch of daylight between our policy position on the Keystone Pipeline and those of the very civil protesters being arrested daily outside the White House,” the head of the groups said in a letter sent to President Barack Obama.
The groups include the Environmental Defense Fund, the Sierra Club, and the Natural Resources Defense Council.
Park police have arrested 275 protesters in front of the White House since Saturday, including the environmental writer Bill McKibben, a former White House official under President Jimmy Carter named Gus Speth, and actress Margo Kidder.
The protest is slated to last until September 3 and organizers say they expect 50 to 60 people per day are willing to risk arrest and pay the resulting $100 fine until the action ends.
Opponents of the TransCanada Corp (TRP.TO) line, which would extend from Alberta to refineries in Texas, worry it could spill oil over a vast source of water in U.S. heartland known as the Ogallala Aquifer, lead to extra greenhouse gas emissions from the energy-intensive processing of the oil sands, and cause destruction of forests in Canada to get to the oil.
They hope to get the attention of Obama, whose administration will decide the fate of the line, but who has been on vacation during the protest.
The State Department is set this month to issue a final environmental assessment of the line which could pave the way for the administration to decide the fate of the line by the end of the year.
Backers of the project say it would create thousands of well-needed jobs and reduce U.S. dependence on oil from countries that are unfriendly to Washington.
TransCanada believes the line will be approved and in service by 2013.
The letter said Obama would “trigger a surge of enthusiasm from the green base that supported you so strongly in the last election,” should he block the project.
“Democrats have to be worried about the youth vote,” said Kert Davies, a researcher at Greenpeace, one of the groups that signed the letter.
Obama has done some things that environmentalists like, such as raising fuel efficiency standards for vehicles. But support from such voters could wane if Obama decides to approve the Keystone line.
“Like it or not greens helped get Obama elected in 2008, but right now many are uninspired,” said Davies.
Reporting by Timothy Gardner; Editing by Bob Burgdorfer