For areas requiring a smaller footprint, the Whooshh Switchback Elver Trap™ is an autonomous system that is ideal for allowing a broad range of eels safe passage around river barriers.

Images are for illustration only, actual designs may vary based on individual customization.

Key Substrate
The Specs
Key Substrate


The Whooshh Innovations EF-16 Climbing Substrate is a durable and modular substrate that is designed to attract and pass a broad cross-section of eels, from elver to yearlings, with a wide range of sizes. 

Original tiles are used throughout the entire ramp except for the uppermost part of the ramp were the end tile is used together with a PVC half pipe (3-4´´ diameter) to create a curved descent to the collecting box (sold separately.) 

The EF-16™ tiles comes with a standard width of 200 mm, a common ramp width of 400 mm needs four EF-16™ tiles per meter of ramp. 

*Specialized tile sizes can be produced

Typical rivet placement, maximum rivet/screw head size: 6.5 mm, five rivets/screws per tile

The Specs

Dimensions of the Switchback

830 x 980 mm x height* 

*Height is the required vertical distance to accommodate 

climb from water surface (incl. river fluctuations) to external 

collection box or Elver Chamber™ 

Dimensions of Ramps

Angle: 30° 

Width: 400 mm 

Length: 920 mm 

Height Options Offered

Sequential switchback increments of 

925 mm 

Proprietary Climbing Substrate: EF-16 

Studded substratum facilitates a “3D” climbing structure 

for more efficient capture over a range of elver sizes. 

Interlocking tiles of 

490 x 200 x 40 mm 

Portion of Ramp Below Water Level 

~1/3 or 1 ft 

Design Features

Requires minimal land use footprint 

Lifts above water surface via guide rails during off season

Addresses elver entry access over a 

range of water surface elevations


Series of short ramp climbs with rest options 

vs. a continuous extended ramp 

Water Flow & Power Requirements

Water Pump

 ~500 l/min 

Flow rate down EF-16 tiles ~ 9-10 l/min 

(on 400 mm width EF-16) via single phase, 230V, 10A (depending on manufacturer) 

Additional Features

Predation Screens: Upper portion shielded 

by perforated aluminum sheet; lower 

portion has stainless steel netting (20 x 20 

mm mesh) 

Retrieval and Transport: Adaptable to 

retrieval of caught elver in collection box or 

the optional Elver Chamber™ which is 

capable of pumping collected elver over a 

barrier or to a more convenient retrieval site