Assessing the Efficacy of Oblique Bubble Screens for Control of Aquatic Invasive Species

Vindhyawasini Prasad, Cory Suski, P. Ryan Jackson, Amy George, Duane Chapman, Jesse Fischer, R. O. Tinoco

Research output: Contribution to journalConference articlepeer-review


Bubble screens are promising low-impact strategies to deter the spread of aquatic invasive species (AIS) in streams. Bubble screens have been successfully implemented to redirect and/or deter adult fish and to capture plastics in some rivers, but their efficacy on invasive fish at multiple life stages (eggs, larvae, and adult fish) is not yet known. Air bubbles rising from a diffuser placed at the bottom of a stream at an oblique angle to the mean flow generate counter-rotating eddies that interact with the mean flow. Understanding such interactions and the relation to the water velocity, river morphology, orientation of the oblique bubble screen (OBS), diffuser material, and airflow rate allows us to design an OBS dispersal barrier, a system able to direct drifting particles (i.e., eggs and larvae) toward the bank of a stream for potential capture. We present the results from a series of laboratory experiments at the Ecohydraulics and Ecomorphodynamics Laboratory at the University of Illinois at Urbana-Champaign, using positively buoyant (specific gravity [SG]=0.9, and diameter [d]=7.09 millimeters [mm]) and negatively buoyant (SG=1.04, d=5.9mm) spherical particles to represent the range of size and density of developing eggs of grass carp (Ctenopharyngodon idella), which is invasive in North America. Experiments focused on a basic OBS system composed of a single porous tube diffuser secured to the bottom of a recirculating flume and attached to a compressed air source with pressure regulation and flow rate control. Acoustic Doppler velocimeters (ADV) and surface Particle Image Velocimetry (PIV) were used to measure the effect of the OBS on the velocity field. Our data show that (1) a single OBS is able to direct drifting particles toward the bank at the downstream end of the OBS, (2) adjusting orientation angle and air flow rate of the diffuser can increase capture efficacy under different flow conditions, reaching up to 100 percent capture for buoyant particles, and (3) the ratio between lateral velocity generated by the OBS (as a function of air flow rate) and the mean longitudinal flow velocities, can be used as an indicator to predict whether the OBS will be able to carry the particles along the full length of the diffuser in wider and deeper streams. The optimal OBS configurations for grass carp egg capture identified by our study can provide the necessary design parameters forfield deployments according to width-to-depth ratios and stream morphology.

Original languageEnglish (US)
Pages (from-to)1565-1570
Number of pages6
JournalProceedings of the IAHR World Congress
StatePublished - 2022
Event39th IAHR World Congress, 2022 - Granada, Spain
Duration: Jun 19 2022Jun 24 2022


  • Bubble Screens
  • Grass Carp
  • Invasive Species
  • Particle Trapping
  • SurfaceVelocimetry

ASJC Scopus subject areas

  • Engineering (miscellaneous)
  • Civil and Structural Engineering
  • Ocean Engineering
  • Water Science and Technology


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