Commissioners approve Holly Street right‑of‑way vacation; neighbors raise long‑running drainage, flood and well‑water concerns

Adams County commissioners approved VAC2025‑1, a request to vacate a portion of Holly Street, after a public hearing on May 27 that included detailed testimony from neighbors and the property’s developer.

Leah Campbell, a planner with the county’s Community and Economic Development Department, told the board the subject right of way and the property receiving it are now within the City of Thornton but, because the right of way adjoins unincorporated Adams County, state statute requires county review (CRS 43‑2‑303). Staff found the vacation would not create nonconforming lots in unincorporated Adams County, would not leave adjoining land without access to a public road and would not pose fire‑access concerns.

Developer presentation and public comment Colin Bowman of Vector Development said the property has been annexed into Thornton and the developer intends to build paired housing (Bowman said 37 residences are proposed) and to extend a regional trail to Thornton’s current standard. Bowman said the site includes an existing detention area that the developer will upgrade and that the city’s engineering requirements are driving extensive stormwater improvements.

Neighbor Lily Ewing, who lives at 10800 Riverdale Road, told commissioners she has had chronic drainage problems for 25 years. Ewing said a pipe installed decades ago has failed, her property floods, and her well water has been contaminated; she said repeated requests to Thornton have not resolved the issue. Ewing told the board she fears adding roughly 29 new houses and the associated vehicle trips and utilities will worsen the flooding and water‑quality problems.

County staff, developers and engineers said the development’s drainage is piped northeast under Riverdale Road and that the developer plans to upgrade the on‑site detention to current code. County engineers said the pipe serving the area is owned and maintained by the City of Thornton, and county planning staff said Thornton has been notified and engaged in ongoing conversations about the resident’s concerns.

Board response and follow‑up Commissioners said the drainage and aging‑infrastructure questions are serious and are separate from the vacation itself. The board asked county staff and the county manager’s office to continue outreach to Thornton to clarify responsibility for failing culverts and pipes that appear to affect unincorporated properties. Commissioner Henson made the motion to approve VAC2025‑1; Commissioner Pinter seconded. The motion passed 4‑0 (one member absent).

An executive‑session request for legal advice on the vacation statute was made during the hearing; the board reconvened and voted on the vacation. County staff said they will track engineering referrals from Thornton and will review any plan materials that show outfalls into county right‑of‑way. The developer said final engineering and plat approvals with Thornton were near completion and that construction would move forward later this year if approvals are granted.

Why this matters The vacation itself transfers a piece of right of way that the City of Thornton will administer; however, public testimony highlighted cross‑jurisdictional infrastructure maintenance where failing pipes and culverts located in one jurisdiction can cause flooding and water‑quality impacts on neighbors in another. The board directed staff to follow up with Thornton and to bring technical plans to county engineering staff if the development’s drainage connects to or discharges toward county property.