Button Rock Spillway Bridge

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at Button Rock Preserve


Project Overview


Button-Rock-Spillway-2015Button Rock Preserve is an approximately 3,000 acre property owned by the City of Longmont on North St. Vrain Creek about 7 miles west of Lyons. The Preserve is maintained by the City of Longmont as a protected watershed that provides the majority of the drinking water for Longmont and Lyons. Both Longmont and Ralph Price Reservoirs are located within the preserve.

During the flooding of September 2013, access to the top of Button Rock Dam and across the Spillway was destroyed. View photos and videos of the damage and repair work throughout Button Rock Preserve >

More information about recreation in the preserve is available on the Button Rock Preserve web page.

Recommended Improvements

As part of restoration efforts in this area, the Federal Emergency Management Agency (FEMA) approved emergency funding to replace access across the Spillway. The City of Longmont worked with FEMA to develop an alternative improved project that involved the installation of a bridge across the Button Rock Spillway.


View a PDF of the bridge design from the specifications document >


The Button Rock Spillway Bridge and all trails in the area are now open for pedestrian access.

The contract for constructing the bridge was awarded to Lawrence Construction, which also built the Martin Street Bridge over Left Hand Creek. Construction on and installation of the bridge began in September 2016 and was completed in March 2017.

Fast Fact: One-hundred percent of the steel used for the Spillway Bridge was milled in the USA.



Funding for this project was contributed by FEMA at 75% of total eligible project costs. The remaining project costs will be split between the State of Colorado and the City of Longmont. The total cost of the bridge is $1,081,000.


The Button Rock Spillway Bridge is a partnership between the City of Longmont and the Federal Emergency Management Agency (FEMA).


Project Manager, Jason Elkins, Civil Engineer I




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