That part of Norfolk has allways been a problem, there used to be a creek there that stretched through the Harrison site over to Monticello Ave where the parking lot is now. That parking lot was the site of a coal gas plant, all the waste got dumped in the creek, think of it as super toxic mud. It is still settling and will be for hundreds of years, and would cost millions to remove. Storm drains that have been installed have settled and flow backward during high tide causing the water you saw today. I worked on the Opera house when during construction and parts of it were built like a bridge to span the old creek so that they would not have to disturb toxic soils, that was less costly than the cost of removing and disposing of the toxic sludge.