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For Immediate Release  • May 7, 2014

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Spring Runoff Making Its Way Through Button Rock Dam

As temperatures rise, snow in the mountains is melting and beginning its journey down to reservoirs, ditches, creeks, and streams throughout Boulder County. Much of the runoff seen in the county is funneled along North Saint Vrain Creek, which feeds into Ralph Price Reservoir, owned and managed by the City of Longmont.

Ralph Price Reservoir and its associated Button Rock Dam remained solidly intact both during and after the September 2013 flood, though, extremely large amounts of woody debris were left in the reservoir and its inlet. After building temporary roadways and completing repairs to severely damaged water supply infrastructure downstream from Ralph Price Reservoir, the City of Longmont was recently able to complete its essential preparations in the area for spring runoff.

Ralph Price Reservoir and Button Rock Dam play an important role in providing water supply for residents and business in Longmont and Lyons, but they are not flood protection structures. Each year, as the weather warms and runoff begins, the City’s Water Resources staff, in consultation with the State Engineer’s Office, begins releasing additional flows through Button Rock Dam. The water is released in a controlled and measured approach. This year, those increased flows began in late April. City staff will continue to progressively increase release amounts, essentially matching the flow of the North Saint Vrain Creek, through May and into June, which is the peak month for runoff flow.

As flows are released, they move downstream along the St. Vrain to and through the communities of Lyons and Longmont. Initially, much of it is diverted to various irrigation ditches. Residents are reminded to stay out of these waterways, especially since early flows can carry some debris. Once ditches reach their seasonal flows, the additional runoff water from Button Rock Dam then travels in the St. Vrain Creek, increasing the flow rates through towns and neighborhoods along its course.

Residents should not be alarmed as flows on local creeks rise through May and June. According to the City’s Public Works and Natural Resources Director, Dale Rademacher, “this is a good thing to bring down the snow pack sooner than later at a more controlled rate.”

The City recently launched a series of Flood Preparedness webpages as part of its flood information website, On the Status and Monitoring page, residents are able to view real-time condition monitoring tools that provide data from creek gaging stations (including Button Rock Dam) and creek cameras. The Flood Preparedness pages also serve as an online resource for residents to review spring runoff preparations undertaken by the City, learn more about factors that can lead to flooding, and, most importantly, understand how to stay informed.



Media Contact:

City of Longmont: Holly Milne, Marketing Specialist, 303-774-4387,

Public Contact:

Public Works & Natural Resources Call Center, 303-651-8416,