Denver is moving ahead with a resiliency project along Sanderson Gulch, but a dispute over beaver habitat is complicating the city’s plan to make the corridor safer for walking and biking and better able to handle floods.
On September 14, the Denver City Council approved a Sanderson Gulch grant resolution in a consent block that includes $4 million in federal PROTECT funding, according to the council record summarized by Legigram.
What the project would change
The Sanderson Gulch Resiliency Project would raise the trail corridor above the five- and 10-year storm levels, replace the existing route with a 10-foot-wide concrete path accompanied by three feet of crusher fines, and add an additional trail underpass, according to the Rails to Trails Conservancy’s description of the PROTECT program.
The reach between the two avenues would be substantially reworked. Denver7 reported that parts of the gulch would become deeper, changing from about 15 feet to 19 feet, while the channel and surrounding corridor would be rebuilt to improve flood protection, trail access and water quality. The project is expected to remain substantially as designed even as the city discusses possible non-structural adjustments with residents, Denver7 reported.
Why Ruby Hill residents object
Ruby Hill neighbors have withdrawn support for the plan in its current form because construction could remove or fragment habitat used by beavers and other wildlife. Residents told Denver7 that they support flood mitigation, safer crossings, trail improvements and better water quality, but want a more substantial ecological assessment before construction begins.
At the September 14 council meeting, District 7 Councilmember Flor Alvidres made announcements. City staff said fundamental changes could affect project benefits, while also saying they were meeting with neighborhood representatives to explore adjustments that would not fundamentally alter the project, according to the meeting record.
The remaining question is how the city will document and address wildlife impacts. DOTI has said it will share ecological information already prepared for the project and discuss whether more information is needed. Officials have also said wildlife would be allowed to move away as construction proceeds, while residents cited by Denver7 questioned whether beavers would return after the corridor is rebuilt. Those competing expectations have not been resolved.
A long-running flood-planning problem
The current project is part of a much longer effort to manage flooding in the drainageway. The Mile High Flood District says its first master plans for Weir and Sanderson gulches were published in 1972 with Denver and Lakewood as partners. That history places the current fight within decades of planning rather than treating the proposed work as an isolated trail project.
The project would add trail and crossing improvements.
Denver’s project materials describe a drainageway that is too shallow in places and has inadequate protection near the Arkansas Avenue culvert. The city’s proposed solution therefore combines channel reconstruction with transportation improvements, creating the central trade-off now before the council and neighborhood: the same construction intended to reduce flood risk would also substantially change one of the corridor’s remaining habitat areas.
The broader beaver-management context
Colorado’s statewide policy direction adds another layer to the debate. The Colorado Parks and Wildlife Beaver Conservation and Management Strategy seeks to increase and sustain beaver and beaver-influenced wetlands in suitable habitats while addressing management concerns, including nonlethal conflict resolution and translocation policy. The strategy does not determine the outcome of the Denver project, but it underscores why habitat and conflict-management questions are relevant alongside flood engineering.
A separate example can illustrate both the possibilities and limits of comparison, but it does not show that the same approach would work in an urban Denver flood corridor.
Next steps
DOTI plans to seek construction bids later this year, with a contract expected to return to the Denver City Council in early 2027. If approved, construction could begin in late spring or early summer of that year, according to Denver7. Before then, the city and residents are expected to continue discussions over what ecological information is sufficient and whether habitat protections can be added without jeopardizing the federal funding or the project’s flood-control objectives.
