Here’s the release from the City of Boulder (Samantha Glavin and Julie Causa):
Due to recent warm weather and increased snowmelt and runoff, Barker Reservoir is expected to start spilling later this week, as early as this Friday, May 28.
This is a normal and expected event that will increase flows in Boulder Creek throughout the city and residents are urged to take caution near the creek during the high flow period, which may last for several weeks.
Each spring as temperatures warm, stream flows increase due to runoff from melting mountain snow. Before peak stream flows occur at lower elevations (like in the city of Boulder), mountain reservoirs must first fill and start spilling.
Barker spill typically occurs between mid-May to late June, with the exact date dependent on weather, snowpack and early spring reservoir levels.
Barker Reservoir has relatively limited storage space, which means that when the reservoir is full, any excess inflow passes over the spillway and continues flowing downstream into Boulder Creek. To provide a sense of scale, the volume of water that flows through Middle Boulder Creek each spring could fill the reservoir multiple times.
For more information on the city’s water resources, visit: https://bouldercolorado.gov/water/water-supply-and-planning.