Glen Canyon Fish Escapement 

Options

Glen Canyon Dam Adaptive Management Program

Technical Work Group Meeting, April 12, 2022

Connie Svoboda, P.E., Hydraulic Engineer

Bureau of Reclamation, Technical Service Center 
Background

• Lake Powell water levels are rapidly declining due to 

historic drought

• As reservoir elevations have continued to drop, the 

epilimnion is nearing the penstock intake elevations

• Risk of downstream fish entrainment has increased

• Non-native game fish above Glen Canyon (smallmouth 

bass, walleye, striped bass) threaten to compete with 

and/or predate the native fish community downstream 

including threatened and endangered species (humpback 

chub, razorback suckers)
Project Goals

• Exploring fish exclusion options to prevent passage 

of non-native fish through Glen Canyon Dam with 

focus on longer-term options

• Determining applicability and scalability for Glen 

Canyon Dam

• Documenting options for further consideration
Approach

•Conduct literature review

• Review devices and techniques used to limit fish 

escapement from reservoirs

• Include physical exclusion and behavioral barriers

•Perform applicable project review

• What has been considered? What has been installed?

• Reach out to every Reclamation region

• Reach out to USACE and other federal/state entities

• Review Fish Protection Prize (2020) outcomes
Approach

•Options Assessment

• What is the applicability to Glen Canyon Dam?

• Determine pros and cons based on criteria such as field 

readiness, applicability, scalability, operational impacts, 

impacts to recreation, maintenance requirements

• Identify which technologies may be most applicable

•Documentation

• Complete report of findings

• Present results at TWG
In-Reservoir Options

•Physical Exclusion

• Exclusion nets

• Fixed screens, conduit screens, bar racks, louvers

• Flexible curtains

• Guide walls

• Deeper water withdrawal through bypass pipes

•Behavioral Barriers

• Bubble Curtains

• Light and Sound Barriers

• Submerged Velocity Jets/Flow Alteration

• Turbulence Barriers

• Electric Barriers

• Floating Booms, Hanging Curtains/Chains
Downstream Options

•At Dam

• Expected Survival through Francis Turbines

• Energy Dissipating Sleeve Valve

•Downstream of Dam

• Downstream Collection/Netting
Example Case Studies

• Lovewell Dam, Kansas

• Reduce fish loss (walleye, crappie, gizzard shad) from 

reservoir during spillway and outlet works discharges

• Fish exclusion net 430-ft-long by 21-ft maximum height

• Elkhead Reservoir, Colorado • Reduce downstream movement of nonnative fish

(northern pike, smallmouth bass) through spillway 

• Fish exclusion net 575-ft-long by about 30 ft-high

•Ridges Basin Dam, Colorado

• Eliminate non-native fish survival from discharge pipe

• Energy dissipating sleeve valve with 0.63-inch holes

•USACE Brandon Road Interbasin Project • Control movement of aquatic nuisance species (invasive Carp)

• Electric dispersal barrier, air bubble curtain, acoustic fish deterrent, flushing flows 

from lock, engineered channel with no habitat
Next Steps

•Continue interviewing subject matter experts and 

reviewing projects that address fish escapement

•Begin options assessment based on applicability to 

Glen Canyon Dam

•Report of Findings – September 1, 2022
Connie Svoboda, 303-445-2152 

csvoboda@usbr.gov