The Englewood Dam in Centennial, Colorado is both a flood control structure and also a great place to walk and enjoy the great views of the mountains to the west and the Willow Spring Open Space to the North and South.
It is at the North end of the Willow Spring Open Space, which has been kept undeveloped to provide a natural flood plain for Willow Creek.
The dam was originally constructed by the WPA (Works Progress Administration) in 1936 after the Cherry Creek Flood of 1933 to control flooding from the Willow Creek watershed and to safeguard areas below the dam along Little Dry Creek.
In 1973, Urban Drainage and Flood Control District (now the Mile High Flood District) assumed ownership of the Englewood Dam. At that time a study showed that it would not have enough capacity for a 100-year flood and so the dam was raised to its current height of 55 feet in 1974.
The Englewood Dam is constructed primarily of clay with occasional sandstone and claystone pieces, which makes it very stable and reduces possibility of leakage through the earth portion of the dam. The basis for this soil is discussed further on the Geology of Willow Spring Open Space post.
Willow Creek goes into the dam at the inlet on the South side of the dam, through a concrete pipe and comes out the outlet on the North side. The inlet looks like a small house but is constructed so that the flow of water through the dam is regulated when there is a high-water event.
The bars on the windows are for safety to keep people and animals out of the inlet and sometimes get blocked by floating debris coming down the creek during floods.
The outlet structure is well protected against people or animals entering into the pipe going through the dam.
On the top of the dam there is a walking path/dirt maintenance road, with some flowers and grasses along the sides. Many people may not know that some of these plants are native plants to the area! The widest part of the top of the dam is 20 feet across.
In 2017 the Urban Drainage and Flood Control District scheduled a project to improve the Englewood Dam. This was a result of a July 2016 study which identified that the dam had settled a few inches, there was rutting from tires of maintenance vehicles, erosion of paths along the dam and there were several species of noxious weeks and bare ground.
The initial changes to the dam were short fences and signage regarding re-seeded areas.
In November and December 2020, Mile Hi Flood District continued the efforts to replace noxious weeds such as cheat grass with native species by reseeding the south side of the dam.
In December, 2020, Mile Hi Flood District constructed fences along the entire north side of the dam top to discourage informal trails caused by bicycling, sledding or walking straight up or down the dam. These trails can cause erosion of the dam and reduce its effectiveness.
Some of those informal trails going up the side of the dam can be seen above the water outlet structure in the photo above.
References and Further Reading
The Urban Drainage and Flood Control District Flood Hazard News, 1973, Volume 3, No. 3, page 6. Accessed 26 March 2021.
Britannica, The Editors of Encyclopaedia. “Works Progress Administration”. Encyclopedia Britannica, 7 Jul. 2020, https://www.britannica.com/topic/Works-Progress-Administration. Accessed 26 March 2021.
South Suburban Parks News and Events Archive, Englewood Dam Maintenance – 2017. Accessed 26 March 2021.