Canyon Lake Has a Working Waterline at 909 Feet

The number 909 has an everyday meaning at Canyon Lake. At elevation 909 feet, the conservation pool is full. GBRA holds the right to store and deliver that water for cities, industry, and agriculture across the Guadalupe basin.

Above that line is a second lake that is usually invisible. The U.S. Army Corps of Engineers manages the space from 909 to 943 feet as the flood-control pool. Keeping it open gives storm water from the upper river somewhere to spread before it moves downstream.

The federal government owns the dam and reservoir, while GBRA holds the conservation-storage right. That split is why a question about stored water may belong with GBRA and a flood-release question may belong with the Corps. It is also a tidy explanation for the lake itself: water supply below the line, storm room above it.