Posted on September 8, 2026
The days of Sloan’s Lake being gross and grimy enough to inspire Reddit posts asking, “Why is [this place] so smelly?” could be numbered.
Why it matters: Denver’s largest lake, which draws 2 million visitors a year, has become dramatically shallower, fueling toxic algae blooms, fish kills and warnings to keep dogs away.
The big picture: Mayor Mike Johnston on Wednesday unveiled a $50 million restoration plan to dredge sludge, rebuild eroding shorelines and filter polluted stormwater before it reaches the 177-acre lake.
- The goal: Make the lake deeper, cooler and healthier for wildlife — and safer and more pleasant for people.
By the numbers: Many areas of the lake average just 2.5 to 3 feet deep, down from historical depths of 8 to 12 feet, according to the city.
Context: For more than a century, stormwater has carried sand, sediment and street runoff into the lake, building up on the bottom.
- The shallower water heats up faster, fueling potentially toxic algae blooms as summers get warmer.
- Dredging would carve out deeper habitat for fish, while green infrastructure would filter runoff and shoreline restoration would curb erosion.
Fun fact: Sloan’s Lake was an accident, according to the Sloan’s Lake Park Foundation.
- It formed in the 1860s after farmer Thomas Sloan unintentionally hit an underground spring.
- Today, its surface area is roughly equal to all of Denver’s other park lakes combined, Denver Parks and Recreation executive director Jolon Clark said Wednesday.
Follow the money: The proposed funding includes up to $40 million from the St. Anthony Urban Redevelopment Area, plus $5 million each from the city’s wastewater fund and Johnston’s voter-approved Vibrant Denver bond package.
- Johnston said the plan would require no new taxes or general fund dollars.
What’s next: The project is in its early stages and needs additional approval from the Denver Urban Renewal Authority board — which officials say could happen as early as mid-September — followed by a green light from the Denver City Council.
- If approved, the city expects to complete contracting and federal permitting in 2027, with work starting in 2028.
- Officials say they aim to keep the park largely open during construction, though parts of the lake may temporarily close.
The bottom line: The hope, Johnston joked: Make Sloan’s Lake “fall-in-able, if not swimmable.”
