Eskimo roll

The picture above is the outlet below the water pumphouse on the aqueduct that runs through LeBreton Flats. The ped bridge is at the top, the beginning of the kayaking course is at the bottom. The water course is variously known as the Tailrace, or Bronson Creek (until the last decade the creek was actually the private property of the Bronson Corporation).

There are three signs in the area. Notice one in the lower centre left of the picture above. Here's a closer up:

It says:
Combined Sewer Overflow Area
Adverse Water Quality Can Occur

I think that is bureaucratic speech (note the lack of a noun, as in who might be responsible for the overflow or adverse quality) for:
Watch Out - Big Sewer Dump Right Here!

I wonder if any of the kayakers feel like doing an Eskimo Roll now??