The purpose of the 2024 LTEMP SEIS is for Reclamation to analyze additional flow options at Glen Canyon Dam in response to nonnative, invasive smallmouth bass and other warmwater, nonnative species recently detected directly below the dam. The recent detection of large numbers of young-of-year smallmouth bass suggests spawning is occurring for the first time directly below the dam. The need is to disrupt the establishment of smallmouth bass below Glen Canyon Dam by limiting additional recruitment, which could threaten populations of the threatened humpback chub below the dam.
|
The ROD states that in 2024, “The Cool Mix Alternative would be implemented until the mean daily water temperature (without bypass) falls below 15.5°C (60°F) at river mile 61.” Furthermore, it states that in any given year for each alternative, “The trigger location for the 15.5°C (60°F) threshold could be anywhere upstream of river mile 61, depending on the smallmouth bass distribution and size class, frequency and efficacy of sampling, or other considerations as determined through the planning and implementation process.” (2024 SMB Flow Offramp - Decision Memo)
|