Enbridge Energy said Friday it will pay a $425,000 fine to settle federal allegations that it made illegal discharges into wetlands and rivers while testing two Minnesota ­pipelines, including one being upgraded to carry more crude oil.

The discharges of high-pressure test water occurred in 2009 and 2010 after the Calgary-based company finished building the two pipelines across the state, but before they were placed into service, the company said in an e-mail.

One of the pipelines, the north-flowing Southern Lights line, transports a light petroleum product used to dilute Canadian tar sands crude oil for shipment. The other line, called the Alberta Clipper, transports the diluted crude oil from Alberta to Superior, Wis.

The U.S. Justice Department and Environmental Protection Agency, in a lawsuit filed this week in U.S. District Court in Minnesota, described 15 cases in which Enbridge allegedly violated its permit as it discharged water after testing the pipelines.

In one case, the government said test water blasting out of a 36-inch pipeline eroded a hillside and ­created a gully 50 to 60 feet long, 15 feet wide and 10 feet deep, leaving up to a foot of sediment in a wetland and sending rust-colored water into the Mississippi River. The blowout happened north of Bemidji, a state inspector said.

"The reason that it's concerning, I'd say, is the sheer number of violations," said Kevin Reuther, legal director of St. Paul-based Minnesota Center for Environmental Advocacy, which mounted unsuccessful legal challenges to block the lines before they were built. "It's as if Enbridge wasn't even trying to comply with its water discharge permit … that it's cheaper to cause whatever environmental damage they want and pay a fine later."

In an e-mailed statement, Enbridge spokeswoman Terri Larson said the company didn't admit to the violations, but decided to settle the case and avoid litigation.

Hydrostatic testing is done as a safety measure and involves pumping water under high pressure into an empty pipeline and checking for leaks. Enbridge obtained a state permit to discharge the leftover water, but allegedly violated the terms.

Larson said Enbridge addressed the erosion ­incidents and reported them to the Minnesota Pollution Control Agency. She said the company has taken steps to avoid future problems, including expanded training, improved sampling and additional documentation.

Last week, the Minnesota Public Utilities Commission approved Enbridge's plan to boost the carrying capacity of the Alberta Clipper pipeline by 27 percent with ­bigger pumping stations. The project is still under federal review.

The upgrade project, like TransCanada's proposed Keystone XL pipeline in western states, is being fought by environmental activists who believe Canadian crude will significantly add to greenhouse gas emissions.

David Shaffer • 612-673-7090