06/11/2026
Longmont has spent 155 years learning to work with water. Some of those lessons came hard.
In June 1921, floodwaters poured down Main Street. In 1935, a levee broke at Terry Lake and flooded the east side of Longmont. In September 2013, the St. Vrain flashed again – this time devastating hundreds of homes, businesses, and miles of public infrastructure across the city. Different decades, same story: a city built at the edge of the mountains, where water moves fast and doesn’t ask permission.
But Longmont has never just absorbed the damage and moved on. After 2013, the City launched Resilient St. Vrain, a multi-year effort to restore the St. Vrain Greenway and make the creek safer for the future. Work started at Sandstone Ranch in 2016 and has been moving upstream ever since. That work helped earn Longmont a rare distinction – the first city in the United States to be named a United Nations Resilience Hub, a recognition given to cities that other communities around the world look to as models for disaster planning and recovery.
Colorado is in drought this year, and across the state, reservoirs are lower than normal. Longmont is responding and drawing on more than 150 years of experience managing a water system that was designed, from the start, to handle uncertainty. That doesn’t make dry years easy. But the same city that built Button Rock Dam and rebuilt a creek after a catastrophic flood is still at work planning for the next 155 years.
Join us every Thursday for the rest of the year as we celebrate the triple anniversary of Longmont turning 155, Colorado turning 150, and America turning 250. We will share stories and photos on specific monthly themes tied to the history of the city we call home. This month, we dive into the history of Longmont’s water.
Visit LongmontColorado.gov/CO150 and check back every Thursday to learn more.
Captions:
Image 1: The 500 block of Main Street during the Terry Lake flood, June 3, 1921 – the “Motor-Cycle Service Station” in the foreground is where Mike O'Shay’s restaurant stands today.
Image 2: The St. Vrain River nearly reaching the top of a concrete bridge, June 3, 1921, with onlookers watching from above.
Image 3: Flood damage near the Great Western Sugar factory, June 1921.
Image 4: A Longmont Fire Department engine pushes through flooded streets during the September 2013 flood, with residents watching from a boat nearby.
