The High Line Canal Conservancy is a great resource for members of the public seeking information about the High Line Canal. Denver Water is responsible for running water through the canal and for completing general maintenance of the canal. There are also stormwater agencies that maintain sections of the canal where stormwater management systems have been put into place. Denver Water has agreements with seven local recreation agencies that are responsible for maintaining the trail and managing recreation:

• Douglas County Parks and Trails
• Metro District of Highlands Ranch Parks and Open Space
• South Suburban Parks and Recreation
• Greenwood Village Parks, Trails and Recreation Department
• Cherry Hills Village Parks, Trails and Recreation Division
• Denver Parks and Recreation
• Aurora Parks, Open Space & Trails

For more information, please visit the High Line Canal Conservancy's page about tree canopy care.

The canal has an 1879 water right, which is fairly junior by Colorado water rights standards. Depending on the availability of water from the South Platte River, and irrigation demand by users on the canal, Denver Water intermittently runs water through the canal between the months of April and October.

All dirt-lined canals seep water. The canal seeps about 60 to 80 percent of the water running through it, making it more suitable for recreation purposes than for water delivery. The canal has been seeping since it opened more than a century ago. Denver Water understands some people who have built below the canal may have problems with normal seepage loss from the canal, but it is not the responsibility of Denver Water, or its partnering agencies, to correct those problems. The canal was in operation — and leaking — at its present location long before development in areas near the canal.

Denver Water and the City and County of Denver are collaborating to address mosquitoes throughout the Denver Metro Area before the 2025 summer season.

Denver Water crews will place larvicide briquettes every two weeks, as needed, in the standing water along the High Line Canal starting in early May. 

• Larvicide briquettes will also be placed in standing water in the High Line Canal following major summer rainstorms. 
• These briquettes contain a bacterium that is deadly to mosquito larvae but harmless to other living things, such as aquatic insects, fish and animals. The treatment takes effect within 24-48 hours and lasts for 30 days. 

Briquettes are the best option for mosquito control. Fogging or spraying for adult mosquito control is not a control method the Denver Department of Public Health and Environment uses. This approach would only be considered and conducted in a manner that balances public and agency concerns for secondary impacts with the level of risk posed to the public by mosquitoes transferring West Nile Virus. 

Denver Water is collaborating with partner agencies overseeing and maintaining sections of the High Line Canal to control and prevent mosquitoes. The City and County of Denver manages the Wellshire, Eisenhower Park and University Hills neighborhoods along the High Line Canal. Residents in those areas can report areas with high mosquito activity by contacting Denver 3-1-1. 
 

Residents can help reduce mosquito numbers on their property by not over-watering yards. Run a short cycle of each sprinkler zone to allow the water to soak in and maintain your sprinkler systems. Residents can also dispose of yard waste through the City and County of Denver’s waste and composting services. Waste should not be disposed of in the canal open space where it can end up in the channel and contribute to sustaining standing water and mosquito production. 

For more tips to help control mosquitoes, read Denver Water’s TAP article, visit the City and County of Denver’s Mosquito Control webpage or go to the Centers for Disease Control and Prevention website at cdc.gov/Mosquitoes. 

Please contact the High Line Canal Conservancy Care hotline for any questions, concerns or claims related to the canal. The Canal Care hotline can be reached at 720-767-2452 or by email at hello@highlinecanal.org.