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Preparations, Longmont Flood Preparedness and Spring Runoff Information

City Preparations

The chart below highlights projects specific to 2014 spring-runoff that the City of Longmont is managing.*




Airport Road Concrete Barriers DONE Read full details in the press release >
Ditch Diversion Structures and Headgates DONE Reconstruction of the Oligarchy Ditch, Rough and Ready Ditch, Longmont Supply, North Branch, Denio & Taylor Mill Ditch, Niwot Ditch, South Flat Ditch, and South Branch Ditch.
Heron Lake -Golden Land Company Drainage Channel

In Progress

A drainage channel from Heron Lake south to the St. Vrain Creek will be constructed to provide protection to the western city limits, north of the St. Vrain, from potential flooding due to spring runoff.
Left Hand Creek Channel Rehabilitation - emergency work DONE Several areas have debris in the channel that will be removed to prevent flooding problems during spring runoff.
Longmont Reservoir and Dam DONE Granular debris removal from Longmont Reservoir, for use in reconstruction of the emergency/temporary Longmont Dam Road, is complete. Longmont Reservoir has been refilled with water. Any remaining material deposited in Longmont Reservoir will be removed next winter (2014/2015).
North St. Vrain Pipeline DONE This pipeline has been restored to full function.
Ralph Price Reservoir Inlet Woody Debris Removal DONE This reservoir, which feeds into the Longmont Reservoir, was filled with extremely large amounts of woody debris during the flood. Work is underway to complete essential removals before heavy spring runoff.
St. Vrain Creek Channel Rehabilitation - emergency work DONE

Three areas of St. Vrain Creek have been identified for emergency channel debris removal to prevent flooding problems during spring runoff:

  1. Airport Road Bridge
  2. Between the BSNF crossing and S Pratt Parkway
  3. Downstream of Main Street

*View a full list of post-flood recovery projects underway for the City of Longmont on our Recovery Updates page.

Boulder County

Boulder County has completed emergency repairs to areas that breached west of Longmont during the flood. For more information, view Boulder County's St. Vrain Creek Rehabilitation page at

Follow other Boulder County flood news and updates at

Resident Preparations

For more information about flood preparations that Longmont residents and property owners can undertake, visit our Office of Emergency Management Flood page.

Boulder County has also produced a Post-Flood Community Preparedness Guide that offers information by section: Safety Routes and Locations, During a Flash Flood, Landslide Safety, Stay Informed, Vehicle Safety, Getting Ready, Before a Flood.


Sandbags are available for pickup by any Boulder County resident at Boulder County Road Maintenance, 5201 Saint Vrain Road (Building 5) in Longmont. For details about this service provided by Boulder County, please visit their Flash Flood Safety webpage, email, or call 303-441-3900.

Sandbagging in neighborhood areas is most successful when used to block water from entering the home itself. It is not meant to provide a diversion from the community or neighborhood as a whole. In order to best block access into the home, sandbags must be placed right up against openings and cracks such as garage doors, window wells, and vents. Also, be aware that sandbags are not indestructible; 95% of sandbags, including those being provided by Boulder County, are made from a biodegradable material and if emerged in water for longer than a day will start to decay. The City of Longmont asks residents to please not try to direct the flow of any water, as this could cause more havoc for your neighbors and put other lives in danger. If you have placed sandbags around your home and an evacuation order is implemented we ask that you still follow City official orders and leave using the safest route possible. Please remember your safety is of the utmost importance during any emergency.