Toponas Rock #2 is a privately owned earth dam located in McCoy, Colorado, along the Toponas Creek-TR. This irrigation structure, completed in 1945, stands at a height of 45 feet and has a storage capacity of 268 acre-feet. With a surface area of 12 acres and a drainage area of 4 square miles, the dam serves the primary purpose of irrigation for the surrounding area.

The dam is constructed mainly of stone and rock foundations, with a spillway type classified as uncontrolled. Despite being assessed as having a low hazard potential and fair condition, Toponas Rock #2 undergoes inspection every six years to ensure its structural integrity. The dam has one slide (sluice gate) outlet gate and a maximum discharge capacity of 570 cubic feet per second, making it a vital resource for water management in the region.

While Toponas Rock #2 poses moderate risk, it remains essential for water resource management in Routt County, Colorado. With its historical significance dating back to the mid-20th century, this irrigation structure plays a crucial role in the local agricultural landscape and highlights the intersection of water resource management and climate resilience in the region.