Elevated bacterial issues in the Sloan’s Lake blue-green algae may force the beloved Colorado Dragon Boat Festival to clearer waters. 

Its been at the west Denver man-made lake for 24 years, since 2001. This year’s festival, already moved from July to September to address the issue, is its 25th anniversary.

Organizers said they may have to move it starting next year. 

The large boating event is typically held in late July, however this year it was announced that it would be delayed until September 6 and 7.

“This shift from our traditional late July dates is the result of a decision by Denver Parks and Recreation to close the lake to permitted events during July and August in an effort to prioritize and improve the health of the lake during the hottest months of the year,” said Sara Moore the executive director of the festival.

Man-made Sloan’s Lake has faced health issues for a large part of its history.

Runoff rich in phosphorus and hot weather creates an excess of blue-green algae, according to Sloan’s Lake Park Foundation Executive Director Kurt Weaver.

Weaver said that sediment falling into the lake continues to make it shallower, and that its lack of oxygen compounds the water quality issues.

It’s currently not even 4 feet deep. 

“That’s why you see fish kills during the summers, because those long stretches of really hot days are what causes it [algae], and the compounding problem of the sediment itself falling into the lake, which is even less deep and shallower,” he said. “So that’s why every day and every year we get closer to the time that dragon boats has to leave because it’s not deep enough to paddle through.”

Moore said the festival will remain in ongoing conversations with Denver Parks and Recreation and keep the community updated on whether this schedule adjustment, or a possible move, in future years.

“With an event that’s been going on 25 years, it’s just tough to think about them going away,” Weaver said.

Some residents are hopeful that the 2025 Vibrant Denver Bond will be able to help with the much-needed cleanup efforts.

In the list of project proposals, Sloan’s Lake is currently set to receive $5 million to improve aquatic environmental health at the park.

Among those improvements could include stabilizing the 177-acre lake’s banks, erosion repair, landscape transformation, wetland habitat additions, green stormwater infrastructure and potential forebays.

However Weaver said that to restore the health of the lake in the long-term, the sediment needs to be taken out and it needs to be restructured.

In the meantime, DPR continues its efforts to monitor and treat the lake water incrementally.

“There’s lots of things we can do, but as you can imagine with a lake that size, or a problem this big, it’s all temporary solutions to then get us to where we have to get the sediment out,” Weaver said.

Many residents remain hopeful that bond funding will be able to help finally address the lake’s water quality in a substantial way.

Weaver said that as a large-scale body of water that is stagnating, Sloan’s Lake is likely a large methane producer and that its cleanup is as much of a climate issue as it is a public health issue.

“I think the end result we want is that our dogs and kids can swim in a lake with water healthy enough to do it,” he said.