The temporary closing of Beaver Lake near Ellendale was caused by a severe algal bloom, not a sewage spill, according to the Minnesota Pollution Control Agency on Tuesday.

The agency stated in a news release it is common to mistake severe algal blooms for sewer or manure spills because they can be similar in odor, but in this case other conditions point to an algal bloom.

“MPCA contractors and staff observed no toilet paper or other telltale signs of human sewage in the sludge on the north side of the lake,” the release stated.

Examinations of the sludge for color, texture and odor were reportedly consistent with algae, not human sewage, and the volume was reportedly too much to be from one individual sewer system or pumper tanker.

Beaver Lake has been closed since Saturday morning because of what was thought to be a sewage spill.

According to the release, because the sludge likely resulted from nutrients washed into the lake from upstream areas and weather conditions, the MPCA is ceasing cleanup efforts designed for spills.

The algal bloom will need time to decompose and disperse, with the length of time depending on rain and cooler temperatures.

The agency expects to receive water sampling results back later this week that will confirm that the incident was a severe algal bloom.

The MPCA advised staying out of the water when there is a doubt about a lake’s water quality.

It is unclear when the lake will be reopened.

Look to the Tribune for more information as it is released.