Sloan's Lake Environmental Assessment

Lake Treatment | Week of July 10, 2023:

The Denver Parks & Recreation (DPR) Lake Management Team is aware of small pockets of bluegreen algae primarily along the southern edge of the lake.  The team is spot treating algae blooms and coordinating with Denver’s Department of Public Health and Environment (DDPHE) to collect samples and monitor the overall health of the lake.  The team is planning a second round of Phosphorous Mitigation Treatment the week of July 10 to reduce the lake's phosphorous load. The Sloan’s Lake Park Operations team practices lake-friendly maintenance by limiting mowing and maintenance of native landscapes, wetlands, and riparian areas to ensure healthy buffers to filter nutrients and debris at the source.  This team also eliminated phosphorous from all park fertilizers.

Help Reduce Phosphorous:
DPR would like to remind neighbors that Sloan’s Lake receives a large amount of stormwater run-off from across the watershed that covers parts of Denver, Lakewood, Edgewater, Wheat Ridge, and unincorporated Jefferson County. All residents of this watershed are encouraged to eliminate the use of phosphorous in lawn fertilizers, clean up and compost your yard trimmings, and remember to pick up after your pets! Due to the exceptionally rainy spring the stormwater run-off has supplied the lake with a considerable amount of nutrients. This coupled with the sudden temperatures increases has created conditions for potential algae growth.

Project Scope

Sloan's Lake is a beloved regional asset in northwest Denver that is in need of environmental improvements to remain a resilient ecosystem and recreational amenity. 

The Sloan's Lake Environmental Assessment will include data collection, analysis, lake restoration planning, and initial concept design alternatives to create a vision for the future of the lake. This project will involve community outreach, education, and engagement. The project will result in a concept plan document and planning level cost estimate to allow Denver Parks & Recreation, Denver Department of Transportation & Infrastructure, Mile High Flood District, and other project sponsors to determine a clear direction and vision to move forward with design and implementation.

Download the Lake Environmental Assessment project sheet(PDF, 157KB)


Sloan’s Lake is a shallow urban lake that has accumulated a significant amount of sediment over the past several decades, resulting in an average water depth of 3.5 feet deep across the lake. In 2020, Denver Parks and Recreation (DPR) partnered with the Denver Department of Public Health and Environment (DDPHE), Denver Department of Transportation and Infrastructure (DOTI) Wastewater Management, and the Mile High Flood District (MHFD) to evaluate the existing conditions of the lake that contribute to an increased occurrence of algae blooms, fish kills, and other aquatic habitat health concerns.

Current Progress

DPR has contracted an environmental consulting firm to perform an assessment of Sloan’s Lake.  This analysis includes bathymetric mapping (a topography map of the lake floor), water quality sensor installation and analyses, and sediment sampling.  Water quality sensors were installed summer 2021 to collect real-time data of the water conditions within the lake.  Analysis of this data will assist in understanding the existing conditions along with changes over time to guide decision making on how to best manage the lake.

DPR is also coordinating with the MHFD to analyze the quality of water entering the lake. This study includes the watershed outside of the City and County of Denver in Lakewood, Wheat Ridge, Jefferson County, and Edgewater.

Next Steps

DPR will gather additional data on the sediment to determine the feasibility and rough costs for possible lake dredging.  The in-lake water quality sensors will be redeployed on the lake surface to collect data throughout the 2023 summer season.

The DPR lake management operations team will also perform a phosphorus mitigation treatment between the hours of 6:00 a.m. and 2:00 p.m. June 5-9, 2023

The boat will be moving slowly across the lake to distribute the product over small sections of the lake each day.  The intent of the treatment is to reduce the amount of phosphorus available to algae, hopefully slowing down its growth and preventing future algae blooms.  The treatment will not impact recreational use of the lake.  Depending on the results of the first treatment, an additional treatment may occur over the summer.

The lake will remain open to hand-launched recreational uses during treatment, however, we strongly recommend you avoid the vicinity of the boat and spray area for safety. As a reminder, avoid contact with the surface water and keep your pets from ingesting lake water.

DDPHE will also assist with collection of water and sediment samples related to both the phosphorus mitigation treatment and ongoing long-term monitoring.  DDPHE will contribute to subsequent analyses, continued assessment and other management actions as needed to support the improvement of the lake’s water quality.

Community Outreach

Virtual Community Meeting #1 | May 18, 2023

At the first Community Meeting about the Sloan's Lake Environmental Assessment, we shared existing conditions that will guide initial concept design alternatives to create a vision for the future of the lake.


En la primera reunión comunitaria sobre la evaluación ambiental de Sloan's Lake, compartiremos las condiciones actuales que ayudaran crear alternativas para el concepto inicial de la visión para el futuro del lago.