Stormwater & Drainage
The City is undergoing a project to update the Longmont Storm Drainage Criteria Manual (LSDCM). The current LSDCM was drafted in 1984. Due to the age, it is severely out of date and has become difficult to implement. The objective of the project is to provide a criteria manual for the City of Longmont that incorporates updated design philosophy for drainage, floodplain and stormwater quality. The new criteria will update the hydrologic dataset with the latest precipitation information, update the design requirements to include the latest tools and processes developed by the Mile High Flood District, and incorporate City specific modifications to the Urban Storm Drainage Criteria Manual Volume III (the currently adopted stormwater quality criteria.
The project has anticipated completion date of 11/30/2025.
Sign up to provide comments on draft chapters.
Program Goals and Services
- Protect people, property and infrastructure from flooding and its impacts.
- Develop master plans for drainage basins in the city.
- Develop floodplain maps with specific information about the flooding risk in each basin.
- Rehabilitate and improve existing stormwater facilities that are aging or reaching the end of their design-life.
- Issue Floodplain Development Permits to manage development within the regulated or effective floodplain.
- Work on drainage improvement projects that are designed and prioritized to provide cost-effective flood protection.
- Projects are financed through monthly residential and business stormwater rates.
- Work to protect and maintain the quality of streams, rivers and other vital water resources including irrigation ditches.
- Longmont’s stormwater drainage system connects directly to the St. Vrain Creek, protecting stormwater quality keeping our waterways healthy and preserving wildlife habitat.
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Button Rock Preserve Closure Due to Red Flag Warning and High Wind Event December 18-19
