Sloan’s Lake is currently suffering, like many colorado lakes, from shallow water, lack of moving water, and a century of human development causing tons of runoff from parking lots, roads, etc. flowing into the lake in the form of sediment. The lake at its health was as deep as 10+ feet in certain areas, and it currently sits at an average of 3.3 feet.
There are 23 storm drains and one large ditch that flow into the lake unfiltered, carrying runoff from streets and parking lots full of sediment and phosphorus rich items like yard clippings, dog poop, fertilizers, etc.
Water stagnates when standing (no movement) and is dangerously shallow. This causes algae blooms, fish kills and other issues. Sloan’s Lake is at this dangerous depth and needs a solution
Thanks to the amazing work of our Parks & Recreation team, they are keeping the lake and surrounding park looking great. But it is an everyday battle to hold back the problems. We need to support them with a longer term solution
The development of suburbs West of Denver created much of the issues we see with the lake. The Sloan’s Lake watershed is the surrounding city blocks, and the towns of Edgewater, Lakewood and Wheat Ridge. This entire region’s runoff has run into Sloan’s Lake historically.
The City and County of Denver, along with the Mile High Flood District believe the majority of Sloan’s Lake sedimentation was caused by the historic, rapid urban develop within the watershed (which includes parts of Denver, Edgewater, Wheat Ridge, Lakewood, an unincorporated Jefferson County) prior to the Federal Clean Water Act of 1972. As the surrounding communities developed, disturbed soils were eroded and washed down the watershed and settled out of the water in Sloan’s Lake. Now that much of the watershed is fully developed and urbanized, we do not believe that significant sedimentation is still occurring from the Rocky Mountain Ditch or the storm drain system. The urbanized watershed is a significant source of pollution and contaminants that run-off paved surfaces into Sloan’s Lake.
Denver has tried a few times through the years (80's and early 2000's) to dredge the lake, both attempts failed for various reasons.
Parks & Recreation installed large ‘filters’ called Forebays, where water runs in and allows sediment to settle before flowing into the full lake. They then clean out the forebay so the process can continue. Currently there is 1 Forebay and 2 Swails (mini forebays) around the lake. The big Forebay is on the north side of the lake (it used to be a green pond) where the Pelican Head statue is located. The Parks & Rec department actively treats the water with anti-phosphorous treatments to prevent blue-green algae. They work hard to keep the plants around the edge of the lake healthy and vibrant so they work as a filter for what runs into the lake. They plant native grasses and plants that serve as filters to replace the non-native Kentucky bluegrass.
The City and County of Denver and Denver Parks & Recreation are working on lake management across the city. Many of the City’s lakes have aerators or water column mixing devices. Sloan’s Lake has a water column mixing device installed in the Marina area. Sloan’s Lake has received 4 phosphorus mitigation treatments, two during the summer of 2022 and two during the summer of 2023. DPR has also adapted park landscape management practices to support lake health including the discontinued use of phosphorus in fertilizers on park land adjacent to streams and lakes.
SLPF is a community neighborhood organization that came together to give the lake a voice and an advocate to fight for its health and future. We welcome all who wish to participate in our mission, which primarily is to:
Where does the money go that you raise?
This is absolutely something we can fix but it will take all of us working together. Sloan’s Lake is not a natural lake. Therefore, it does not function like a natural lake, nor does it truly function like a reservoir or manmade lake. The solutions will need to be creative and adaptive. The ecological consultant currently running an assessment of the lake is tasked with creating data-driven restoration concepts to help inform future projects on and around the lake to improve water quality, ecosystems and recreational access.
Short Term we must:
Long term we must:
There are two permanent water quality monitors in the lake that tracks real time data accessible to DPR’s Lake Management Team and Denver’s Department of Public Health and Environment. One is located in the center of the lake and one in Cooper’s bay. There is also a SolarBee installed in the Marina area. The SolarBee is a water column mixing device.
Size of the lake is too big for fountains to make any difference with Fountains. Because this lake was just a depression in the ground, lightly contoured by Farmer Sloan, it was not made with water quality and movement in mind.
The lake is primarily managed and maintained by Denver Parks and Recreation (DPR). However, maintaining an urban lake takes a village! Sloan’s Lake acts as flood storage during large storm events and the flood capacity is regulated by Denver’s Department of Transportation and Infrastructure (DOTI). The Water Quality is monitored by Denver’s Department of Public Health and Environment (DDPHE). DDPHE and DPR work closely together to proactively and reactively treat water quality issues, including blue green algae blooms. These partners, along with the Mile High Flood District, will jointly develop future engineering and ecological solutions for the lake. They can also use your help!
The city does not currently have a project to “fix” Sloan’s Lake currently funded. It will take a coalition and many years to move this effort forward to engineering and design. The Environmental Assessment the City is currently running is the first step in the planning process to determine a rough order of magnitude to allow us to start discussing how this fits into the project partners budgets.
The dredging project in the early 2000's ended up failing due to the contractor going bankrupt. This stalled and eventually ended the project, and left a bad taste in the community's mind on dredging projects. This is not the same process that would be used to dredge the lake today, and we will ensure funding is available to complete the full project.
Our best estimate is a 3 year project. Permitting alone would take a year to complete, and there still needs to be more environmental assessment, testing of the water and lake bed, Plan the entire project, find the money for the project, and then run it to completion
Dredging done right, and mitigation of the issues that caused dredging will last decades and even longer. Other issues will certainly face our waterways in the future with climate change, but this will not be something we need to revisit soon if done correctly.
All of Denver’s Park Lakes are open to hand-launched boating - including kayaks or paddleboards. All Trailer Launched boating including, motorized boats and sailboats, are currently prohibited. Please see the Denver Parks boating webpage for more information or sign up for an Outdoor Recreation Activity. The lake is generally safe for “incidental” contact from paddlesports. The City discourages people (and dogs) from swimming in any of Denver’s lakes or waterways. Denver’s lakes and streams receive runoff from city streets, yards, parks, and discharges from industry and wastewater treatment plants. Sometimes pollution in the runoff and discharges, which includes bacteria such as E. coli, can make residents sick.
Sloan’s Lake is a flood Plain that can raise 2.5 feet from its current height before flooding outside the park. It is meant hold immense amounts of water and support flood remediation. The Lake can detain the “100 year flood” event. So risk of flooding outside of the lake banks is not likely.
No, the current irrigation system pulls from the city water system so it does not use lake water. After a repair of the pump system this year, they will reevaluate the use of lake water in future years
Yes, they have stopped stocking fish in Sloan’s Lake until the water is healthier. The fish you see in the lake are mostly carp and other varieties that survive the issues
There are currently no plans to install a dock at this time. This could be an item considered during the vision planning for the Gun Club Building and Southeast corner of the site set to kick-off planning and public engagement in early 2024.
There are currently no plans to install Pickleball courts at this time. This could be an item considered during the vision planning for the Gun Club Building and Southeast corner of the site set to kick-off planning and public engagement in early 2024.
The south tennis courts will be complete in mid October. Design of the courts on the north side will kick-off in early 2024 with an abatement process and construction to follow. A project timeline has not yet been set.
There is only one outlet that releases water from Sloan’s Lake. This outlet is set just above the normal water surface elevation of the lake and only releases stormwater from large rain events. This is considered the “detention” capacity of the lake. When the lake was open for motorized boating, the engine wake stirred up the lake water and sediment that caused some additional discharge into the South Platte RIver. With the discontinuation of motorized boating this issue has decreased.
Denver Parks does not have an official name for the island (but we will work on that!)
False! Sloan’s Lake became a “Designated” Park in the City and County of Denver in 1956 through City Ordinance. This designation preserves the property exclusively for park purposes under City Charter. This protection ensures our parks, like Sloan’s, remain parkland indefinitely and will not allow the property to be developed by the City or any other entity for any other land uses.
According to legend, in 1861, Thomas M. Sloan tapped into a water aquifer while digging a well to irrigate his farmland in what is now considered West Denver. Almost overnight, the lake spread to a whopping 200 acres and soon attracted onlookers to confirm rumors of a new body of water, graced with monikers such as “Sloan’s Leak,” “Sloan Lake,” and “Sloan’s Lake,” a name that would continue to be debated over a century later. The farm and an ice house on the lakeshore soon became prosperous sources of income for the Sloan family. Activities such as boating, swimming, and ice skating made Sloan’s Lake a popular recreational attraction in Denver. In 1872, Thomas M. Sloan sold his property after placing an advertisement in the Rocky Mountain News for the sale of “the best farm in Colorado.”
In December 1866, under the newly enacted Southern Homestead Act, Thomas M. Sloan received a patent for the land from US President Andrew Johnson to use the land for agricultural purposes, farming, and cattle-raising. A commonly accepted legend states that Sloan dug a well on the land, inadvertently tapping into an underground aquifer, and that when he awoke the next morning, part of his farm land was covered in water. That flooded this part of South Golden Road, and the realigned thoroughfare, now known as Colfax Avenue would become the major east-west thoroughfare in this part of the city. But, according to gold rush era stagecoach driver Bill Turner, the lake appeared sometime between when he left for Kansas in June 1861 and when he returned in early 1863. It is possible that Sloan occupied the land prior to patenting it. However, its unlikely Sloan would have applied for a patent to farm land that was under water and just as unlikely that the patent would have been granted under the Southern Homestead Act.
Manhattan Beach was one of Denver’s first amusement parks and was located on the North shore of Sloan’s Lake. When the park opened its doors in 1891, it was considered the largest amusement park west of the Mississippi. The park was the vision of German-born Adam Graff, an ambitious immigrant who was an ice cutter at Sloan’s Lake. With funding support from brothers Robert and Ernest Steinke, they were able to open the park while continuing to add newer attractions such as a roller coaster, a dance hall, a zoo, a skating rink, a theater, and more. The beauty of the park burgeoned as thousands of trees, shrubs, and potted palms were planted in the gardens and picnic grounds. A total of 10,000 visitors traveled from all around Colorado by way of horse, buggy, and streetcar for the grand opening. Manhattan Beach lured patrons not only with its beauty, but also with its growing variety of attractions, performances, and athletic events held at the park. A pleasure barge named “City of Denver” was a Denverite favorite for its gentle cruises in the afternoon and late evenings. Circus acts, live bands, gypsy groups, baseball games, and boxing matches were all attractions that kept visitors returning. People enjoyed the view of ascending hot air balloons while acrobats were shot out of cannons. New animals such as camels, tigers, lions, elephants, and various Colorado wildlife were continuously added to the zoo within the park. There was even a Cinderella coach hauled by a pair of ostriches!
The park’s popularity was short-lived as it suffered from a series of unfortunate events.
The area surrounding the lake was once home to an amusement park and swimming facility known as Manhattan Beach. Opened to the public 27 June 1881, it was the first amusement park to be built west of the Mississippi River (it burned down in 1908 and was rebuilt as Luna Park later that year); mishaps, and competition from other such attractions in the vicinity (Elitch Gardens and Lakeside Amusement Park), led to its closure in 1914
Roger the Elephant's legend is one of many fanciful stories, but the truth is as exciting as any legend could be. Roger was the main attraction at the Manhattan Beach amusement park. One day a child, George Eaton was riding Roger when he slipped off and Roger trampled the young boy to his death. The account in the Rock Mountain News is gruesome and should only be read if you have a strong stomach. After the incident, Roger's popularity fell and soon after the park stopped marketing Roger in their ads. He was sold to another amusement park and his whereabouts unknown after the sale. This incident also prompted the owners of Lakeside and Elitch Gardens amusement park to march to Manhattan Beach and 'declare war' in an attempt to steal the animals in their care. No, Roger is not buried under King Soopers, and No, he is not buried in Sloan's Lake...or is he… (he is not, he was sold to another owner and accounts have him leaving town but the records end after that)
Cooper Lake, a separate body of water just southeast of Sloan's Lake, fell under the jurisdiction of the federal Works Projects Administration in the 1930s, and a plan was developed which involved building channels beneath the surface of the water on both lakes. This essentially created one body of water that has commonly become known as Sloan's Lake. The size of the present-day combined Sloan's Lake and Cooper Lake is 177 acres. The island created currently has no official name
The Denver Trap Shooters Club operated on the Southwest Side of Sloan's Lake from 1923-1969, and used the Gun Club building that exists today. They shot trap and skeet over Sloan's Lake and the location was open to the public as part of the municipal recreation program.