The National Fish and Wildlife Foundation operated on a modest budget in relative obscurity for nearly three decades. Then it won the lottery.

Over the next five years, BP will give the foundation nearly $2.4 billion as part of the $4 billion settlement with the Justice Department announced Thursday stemming from BP’s disastrous 2010 Gulf of Mexico oil spill.

The foundation’s executive director, Jeff Trandahl, usually spends his time defending federal funding from the budget ax and cajoling corporate titans into making contributions. On Friday, he was fielding a slew of calls as people asked him how he might start spending millions of dollars.

“In conservation, everyone’s been waiting for this day,” he said. “This is the first step forward toward restoration and recovery. Now, the question is how do the troops start moving forward.”

The decision to steer so much to a single group sparked questions from some invested in the settlement’s outcome, including Sen. Mary Landrieu (D-La.) and a few environmentalists.

Landrieu praised that the money was being used “in a creative way to leverage it with private dollars” but expressed concern that the foundation’s board “includes only one person from the Gulf of Mexico. I would have liked to have seen a little more representation from the Gulf Coast, but at least the work they’ve done along the Gulf Coast has been very good.”

The foundation — created in 1984 by Senate Republicans seeking new ways to muster conservation funding in the face of Reagan administration budget cuts — is not an environmental advocacy organization. It receives an annual appropriation of about $15 million from the government, along with other federal grants totaling as much as $45 million, and solicits donations of about $16 million a year from private donors and corporations including Wal-Mart, Shell, Southern Co. and the American Petroleum Institute.

In its 28-year history, it has been responsible for $2.1 billion in conservation projects around the country, from acoustic monitoring of marine mammals in the Arctic to restoring fish habitat in the Ozarks. The next five years will more than double that figure.

Still, few other groups were as well-positioned to dole out the massive funds BP has agreed to hand over as part of its agreement with federal officials. The foundation oversees environmental grants and contracts totaling $75 million to $100 million a year, working with state and federal agencies as well as scientists, environmental groups and landowners to address threats to fish, wildlife and the habitat on which these animals depend.

“We are somebody who brings together all the experts to identify a strategy, and are focused on outcomes,” said Thomas Kelsch, the group’s vice president for conservation programs.

And it is a group trusted by BP, which already gave it $22 million in profits that BP got for selling recovered oil from the 2010 spill.

That money has funded 77 projects in five states, including saving 80,000 to 100,000 sea turtle hatchlings annually and protecting bird nesting sites on 30 islands and beaches.

While the technology required to drill — and cap — an oil well in deep water can be mind-boggling, cleaning up the spill required mostly tedious manual labor.

Ducks Unlimited chief executive Dale Hall said the foundation’s management of these funds “is good news for the people and wildlife of the Gulf Coast.”

Trandahl, a former GOP Hill staffer who served as Clerk of the House before leaving to head the foundation in 2005, said he does not apologize for soliciting donations from corporations whose activities are connected to environmental degradation.

“Sometimes those companies that have the greatest issues are the ones I’m going after because they are doing harm to the environment, and I think they have the obligation to give back,” he said.

BP spokesman Scott Dean declined to comment on the matter Friday.

The money BP will hand over in the course of five years has strings: The Justice Department, which made the decision to put the foundation in charge of the money, included language in the settlement agreement regarding how it will be spent. Half will go to restoring Louisiana’s barrier islands and coastal habitat; the other half will be divided among Alabama, Florida, Mississippi and Texas, with the first three states getting equal shares and Texas 16 percent.

“There are tight restrictions around the money,” said Timothy DiCintio, who handles what the foundation receives from legal settlements.

While the group has received money from state and federal criminal cases before, the largest sum it had received before Thursday was about $13 million. Still, it can disburse funds relatively quickly: Upon receiving $5 million from BP on June 20, 2010, less than two months after Deepwater Horizon exploded, the foundation committed it all within a month.

Kert Davies, research director for Greenpeace U.S., said that while the group has done helpful restoration work, it also appears to be “a safe place for corporations to give their money because they’re not going to criticize corporations.”

Shell spokesman Bill Tanner, whose group gives $1 million a year to the foundation, said it has focused on marine habitat projects in the gulf as well as in Alaska’s North Slope and North Aleutian Basin.

“It’s the most important conservation group no one’s ever heard of,” said George Cooper, who specializes in conservation issues as a senior vice president for the lobbying firm Forbes-Tate.