Emergency crews are working to clean up a leak from an oil pipeline under the Red Deer River in central Alberta that left an oily sheen on a popular resort and boating lake.

The leak was discovered about 10:30 p.m. Sunday in a section of pipe underneath the river about five kilometres north of the town of Sundre. Between 75 and 125 barrels of oil escaped before the pipeline was shut down.

An aerial survey team from pipeline operator Pembina Pipelines, the Energy Resources Conservation Board and Alberta Environment spotted an oily sheen Monday morning on Glennifer Lake, a popular resort and boating lake about 33 kilometres downstream.

"We haven't detected any oil on the Red Deer River,'' said ERCB spokesman Davis Sheremata. "Due to heavy rains, the water in the river is moving really fast.''

At the lake, one resort operator has shut down his water treatment plant for a few days while the oil is cleaned up.

"We've got enough water for a couple days,'' said Jim Rasmussen of the Glennifer Lake Resort.

He said there are between 400 and 500 people staying at the resort this week, a number that swells up to 1,500 on weekends.

Rasmussen said he went to have a look at the lake Monday morning and couldn't spot anything on the water that looked like oil.

Kent Adler, who manages the 299-site campground on the lake, said he visited his campers this morning to let them know about the spill.

"It's supposed to be contained by the mouth of the lake,'' he said.

Alberta Environment and other clean-up crews are at the Pembina Pipelines site near Sundre. Crews are also setting up booms in the lake.

No injuries were reported and the Energy Resources Conservation Board is investigating.