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New projects take shape along High Line Canal

Denver Water pledges $10M to long-term care of the historic canal.

When Denver’s early settlers built the High Line Canal back in the 1880s, little did they know what the future would hold for the 71-mile man-made waterway that stretches from Waterton Canyon southwest of Littleton all the way to Aurora.

The High Line Canal was originally designed to deliver irrigation water to farmers on the dry plains of Denver. While Denver Water still owns and uses the canal to deliver irrigation water to customers, the canal corridor also has grown into a recreational asset and an ecological resource for the metro area. 

On the recreational side, each year around 500,000 people walk, run and ride the canal’s 71-mile maintenance road that also serves as a popular trail. As an ecological resource, some sections of the canal structure itself are now being used for stormwater management. 

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Crews build the High Line a century ago
The High Line Canal is an irrigation ditch built in the 1880s. Denver Water still uses the canal to deliver irrigation water to customers when conditions allow. Photo credit: Denver Water.

The evolution of the public’s use of the canal for recreation and stormwater management, along with its original role as a water delivery method, is one of the reasons why Denver Water and regional partners, including cities, counties, park and flood districts and stormwater management entities, have partnered with the High Line Canal Conservancy. The nonprofit organization’s mission is to preserve, protect and enhance the 71-mile canal in partnership with the public. 

Denver Water plays an active role in the ongoing discussions about the canal’s future as it continues to serve its High Line customers. Because the canal has a junior water right and experiences high seepage and evaporation losses over large distances, Denver Water is looking for more reliable and efficient ways to deliver water to some of the High Line customers.

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Debris stuck in the High Line
The High Line Canal in operation in May 2021. The canal is an inefficient means of delivering water long distances. It can get clogged with debris and loses 60% to 80% of its water to the ground due to seepage. Photo credit: Denver Water.

“As the canal’s role in the metro area evolves, Denver Water is committed to making sure it remains a beneficial asset to the community,” said Jeannine Shaw, government relations manager at Denver Water. “That’s why in 2020, the Denver Water Board of Commissioners approved a historic $10 million pledge to the High Line Canal Conservancy to invest in the long-term care and maintenance of the canal corridor.”

Included in the pledge is a piece of property and an office building located adjacent to the canal in Centennial for the Conservancy to use as its new headquarters.

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High Line Canal Conservancy headquarters
The High Line Canal Conservancy’s new headquarters is located along the canal in Centennial. Denver Water provided the building to the nonprofit as part of a financial pledge in 2021. Photo credit: Denver Water.

As part of this evolution, the Conservancy, Denver Water and canal stakeholders are creating a new management structure called the Canal Collaborative to formally connect the regional partners as they guide the future of the canal.

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High Line Canal Conservancy Collaborative group photo
Representatives from the Canal Collaborative pose with supporters for a picture to celebrate their work. Photo credit: High Line Canal Conservancy.

“The collaborative helps us do more together than any one entity can do alone,” said Suzanna Fry Jones, senior director of programs and partnerships for the High Line Canal Conservancy. “The collaborative management structure will ensure this treasured resource is preserved, protected and enhanced as a regional legacy for future generations.”

The formalized structure will benefit citizens and the environment along all 71 miles of the canal as it winds its way through Denver as well as Adams, Arapahoe and Douglas counties.

The Canal Collaborative includes the High Line Canal Conservancy, Denver Water, Arapahoe and Douglas counties, the cities of Aurora, Denver, Cherry Hills Village, Greenwood Village and Littleton, the Highlands Ranch Metro District, the Mile High Flood District, the Southeast Metro Stormwater Authority and South Suburban Parks and Recreation.


Read about the different canals that carry water through Denver Water’s complex system. 


“The collaborative is important because we need to have a group that brings together all of the jurisdictions so we can hear from each one of those entities and their communities about what’s most important to them,” said Nancy Sharpe, Arapahoe County Commissioner for District 2, which includes Centennial, Greenwood Village, a portion of Aurora and unincorporated central Arapahoe County.

The Conservancy was formed in 2014 and has developed “The Plan for the High Line Canal,” which lays out guidance for repurposing the corridor along with over 100 recommendations for new projects.

Here’s a look at some of the developments along the canal in recent years.

Ecological resource

Under the new Stormwater Transformation and Enhancement Program, High Line Canal partners are looking at ways to allow and move stormwater through areas of the canal to improve water quality and manage local flooding in the South Platte River Basin. This is in addition to the canal’s existing irrigation delivery purposes.

Stormwater is any rain and snow that eventually flows off any impervious surface and into the canal.

Several structures have been built in or on the side of the canal to help manage the flow of stormwater through the channel. 

The new structures that are located on the side of the canal help improve drainage on city streets and collect debris and trash before water enters the canal. 

The structures being built inside the canal also help catch and stop debris and trash from flowing down the channel. They also temporarily slow down and detain water to filter out sediment. 

These structures are designed to improve water quality before the water reaches receiving streams. Moving stormwater through the canal could provide an additional 100 days that the canal could be wet in some parts of the channel, which would benefit vegetation along the corridor while also enhancing the recreational user experience.

“Often times across the country, old utility and railroad corridors become degraded once their primary uses have been reduced, so we’re happy to see areas of the High Line Canal being maximized and transformed into green infrastructure,” Shaw said.

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Snow and rain draining through a stormwater pipe
The City of Littleton built a stormwater management system on Windemere Street. Snow and rain drain through a grate on the street and into a pipe that flows into the High Line Canal. Photo credit: Denver Water.
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Street with concrete edge
The City and County of Denver built four “drive-through forebays” at the end of several streets next to the High Line Canal across from Eisenhower Park. Before the structures were built, stormwater would flow uncontrolled and unfiltered into the canal. The forebays act as pre-treatment structures that will slow water down and allow sediment and trash to settle onto the street before entering the canal. Photo credit: Denver Water.
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Rock and concrete to control water flow
The City and County of Denver built three concrete structures called water quality berms in the canal. This structure in the canal at Wellshire Golf Course will control the flow of water and catch trash and debris, making it easier to remove while providing cleaner water. Photo credit: Denver Water.
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Gate in High Line Canal
A new water quality berm with a headgate in the High Line Canal at Eisenhower Park in Denver. The berm temporarily detains stormwater to promote filtration of sediment before water passes through to improve water quality in the canal’s receiving streams. Photo credit: High Line Canal Conservancy.
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Open concrete gate at stream crossing
When the High Line Canal is not in operation, gates are fully opened at stream crossings. This allows stormwater that’s been filtered in the canal to go into receiving streams such as Big Dry Creek at deKoevend Park in Centennial. Big Dry Creek eventually flows into the South Platte River. Photo credit: Denver Water.

Along with Littleton and Denver, stormwater projects are also being implemented in Centennial, Douglas County and Greenwood Village with additional projects in progress. Learn more about the Stormwater Transformation and Enhancement Program in this video.

Denver Water and its regional partners also are exploring other opportunities to allow the canal structure to be used. In areas where it has adequate stormwater capacity the canal could provide additional benefits to the neighboring communities and their surrounding environment to improve water quality in the South Platte River basin.

“As we navigate the evolving future for the lands the High Line Canal irrigates, Denver Water is excited to further the work with our regional partners to find additional utility for this cherished resource,” Shaw said.

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Dry, empty canal
The High Line Canal in September 2021, near the South Quebec Way trailhead in southeast Denver. The canal is dry most of the year when not in operation for irrigation deliveries. Moving stormwater through the channel improves water quality and could add an additional 100 days when the canal could be wet in some parts of the canal. Photo credit: Denver Water.

Tree canopy health

There are more than 23,000 mature trees along the High Line Canal, but many are at the end of their life span. The Conservancy is working with Denver Water and regional partners to remove dead trees and trim others to improve overall tree health and safety along the canal’s recreational trail.

To maintain the canal’s urban forest, the Conservancy’s Plan recommends planting 3,500 new trees by 2030. The species of trees being planted will be more drought tolerant than many of the old cottonwood trees currently along the canal. 

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Two people planting a tree
In the fall of 2021, the Conservancy, along with the support of local volunteers and The Park People, planted 175 new, drought-tolerant trees. Photo credit: High Line Canal Conservancy.

Trail improvements

A major goal of the Conservancy and the Canal Collaborative is to make it easier, safer and more fun to walk or ride on the canal’s recreational trail. The Conservancy is working with local jurisdictions to add new pedestrian bridges, trailheads, underpasses, mile markers and wayfinding signs.

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Cyclist on the High Line
A biker rides through the new underpass that goes under South Colorado Boulevard and East Hampden Avenue next to Wellshire Golf Course in south Denver. The project provides a critical connection to allow safe passage under two busy streets, resulting in easier trail access and encouraging more users. The collaborative project was funded by the City and County of Denver, Cherry Hills Village and Arapahoe County along with funds from the federal government. Photo credit: Denver Water.
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Informational sign on the High Line trail
A new sign along the High Line Canal trail in Aurora installed in 2021 provides a map to help trail users navigate the corridor. Photo credit: Denver Water.
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New trailhead along the High Line
Arapahoe County Open Spaces opened a new trailhead on South Quebec Way in southeast Denver. The site includes parking, a bathroom, a trash can and a trail map. Adding new trailheads is major goal of the High Line Canal Conservancy to improve access and facilities for the public. Photo credit: Denver Water.

Canal Improvement Zones

Under The Plan, the Conservancy has worked with the community and jurisdictional partners to identify nine Canal Improvement Zones. These are locations where residents asked for trail enhancements to increase physical activity, foster community connections and create access points to nature.

Many of the sites are in diverse neighborhoods where the canal corridor has been historically under-utilized and lacked investment.

Enhancements may include pedestrian bridges, improved trail access, benches, signs, gathering spots and play areas.

The first location to see new projects is the Laredo Highline neighborhood in Aurora, thanks to a $180,000 grant from the Colorado Health Foundation and an additional $180,000 from Arapahoe County.

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Rendering of trail enhancements
A rendering of enhancements to the High Line Canal trail in Aurora’s Laredo Highline neighborhood. The enhancements include a new pedestrian bridge to improve trail access and new play and seating areas. Image credit: High Line Canal Conservancy.

“I grew up in the Laredo Highline neighborhood and the canal has always helped bring the community together,” said Aurora resident Janak Garg. “We’re really looking forward to the new bridge and other improvements coming to the neighborhood.”

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Family on High Line trail
Janak Garg and his family stand at the spot where a new pedestrian bridge will be built across the canal in Aurora’s Laredo Highline neighborhood. Photo credit: Denver Water.

New mile markers

A very noticeable and welcome improvement to the trail is the addition of new mile markers. In the past, there were a variety of mile markers with different mileage from each jurisdiction, which made it confusing for hikers and bikers. 

Now there are new Colorado red sandstone mile markers that line the trail from start to finish, paid for through donations by the Conservancy’s founding partners. 

Most of the markers have a quote or message from the founding partners, like Al Galperin who lives near the South Quebec Way Trailhead, whose message reads: “Be the reason someone smiles today.” 

“I hope it brings a little bit of extra joy to people on the trail,” Galperin said. “It’s nice to be able to help out and see all the new features coming to the canal.”

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Man with dog on High Line trail
Al Galperin and his dog Brody stand next to one of the new mile markers along the High Line Canal trail. Galperin is one of the High Line Canal Conservancy’s Founding Partners who made a donation to help fund the mile marker project. Photo caption: Denver Water.

“It’s inspiring to see all these improvements and we’re excited for the future of the canal,” Shaw said. “The Conservancy and all of the partners are doing a great job leading the way and working with Denver Water and the community.”

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Denver Water crews and volunteers pose for photo
Denver Water crews participate with volunteers to help clean up the canal in Aurora in April 2021. Photo credit: Denver Water.

Visit highlinecanal.org to sign up for monthly emails for information on events throughout the year. The website also provides information about history of the canal, new projects and volunteer opportunities.