Last week Horsetooth Reservoir was placed on Colorado's 303d list (final list due next month) by the State Water Quality Control Commission. Here's an article from the Fort Collins Coloradoan about low oxygen levels and the impact.
From the article, "Save for a bout of orange-tinged water in September 1989, dissolved oxygen issues at Horsetooth Reservoir have been largely invisible to Fort Collins water customers.
"Continuing dissolved oxygen problems, however, could start to show up on city rate payers' bottom line, treatment managers say.
"When the amount of oxygen dissolved in water gets too low, metals such as manganese can be released from nutrients in the lake.
"That's what happened in 1989, when enough manganese was released to overrun the city's treatment and turn tap water brownish-orange. While the water was unsightly, the level of manganese wasn't enough to harm humans.
"Fort Collins responded with a $700,000 chlorine dioxide system that has cost the average customer 41 cents to 97 cents a year since 2001."
Category: Colorado Water