The RTD has a look back at the 1981 James River algae outbreak that funked up the city’s water supply:

When a heavy concentration of algae reached the city’s water-filtration plant on Douglasdale Road “in a big gush” the morning of Sept. 29, the Richmond Department of Public Utilities promptly closed the plant’s intake gates. They remained closed from noon until 8 p.m., while local and state health departments tested water samples. Testing showed the bloom was a nontoxic variety of blue-green algae, so the water was deemed safe for consumption.

But the city’s water supply almost became unusable because of its woodsy taste and musty smell. In an effort to tame the water’s offensiveness, the city tried using more activated carbon in the water-treatment process to neutralize algae wastes. The extra carbon helped, but it could not eliminate the problem.