Grand Canyon Hydraulics and Humpback Chub

Robert Gonzalez

Abstract: The installation of Glen Canyon Dam on the Colorado River in 1963 was detrimental to the native humpback chub (Gila cypha) fish populations because the flow, sediment, and temperature regimes the fish evolved with were drastically altered. The humpback chub is listed as an endangered species, which has prompted a number of studies to better understand its lifecycle and behavior. Several efforts aim to restore humpback chub populations so it can be down listed. Humpback chub partially motivated recent high flow experiments that will continue through 2020. Roughly 90% of the Grand Canyon humpback chub population is concentrated near the Little Colorado River confluence, where there is access to seasonally varied flows and temperatures.