The existing 90-year-old spillway is located left of the earth-filled dam.
Wayne Pullan, Upper Colorado Basin Regional Director for USBR, explained: “The spillway at Hyrum Dam is used every year to release excess water downstream, and though continuous maintenance has occurred on the spillway since its construction, the 90-year-old structure is in need of replacement.” The aging infrastructure has prompted this significant upgrade.
Work is set to start later this year. Ahead of construction, USBR is replacing the dam’s original 24-inch outlet piping with 36-inch piping, boosting the discharge capacity from 50 to 200 cubic feet per second. Rick Baxter, Provo Area Office Manager, noted: “Working with our project partners, Reclamation will continue to take every precaution at Hyrum Dam. That includes our current work to expand the size of the dam’s outlet works so more water can be conveyed through the outlet and alleviate additional stress on the existing spillway until a new one is built.”
Over the decades, USBR has maintained the spillway and managed limited releases. During heavy runoff periods, staff have monitored the structure 24/7 and kept equipment on standby for potential urgent fixes. The South Cache Water Users Association oversees the dam’s daily operations and upkeep. This contract comes after years of planning with partners, with an environmental assessment finalized in January 2024, confirming no major ecological concerns.
The project focuses on improving infrastructure resilience, ensuring reliable water management for local use without impacting broader trade dynamics like exports or consumption. The enhanced outlet capacity will help handle water flow more effectively, reducing strain on the old spillway until its replacement is complete.
This effort reflects a practical response to aging facilities in northern Utah. By upgrading Hyrum Dam, USBR aims to maintain its role in supporting irrigation and municipal water needs. The collaboration between federal agencies, contractors, and local operators underscores a shared commitment to safety and functionality. Construction progress will bring a modern spillway to a nearly century-old dam, securing its service for years ahead.
