• Whooshh Elver Collection Solutions


We don't like to keep any secrets here at Whooshh Innovations. These are our solutions specification sheets, so you understand exactly what you're looking at. Something doesn't make sense? Don't be afraid to ask.


Elver Floating Collection

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Elver Trap

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Proprietary  Lever Climbing Substrate

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Water Flow
Power Requirements

Dimensions of Assembled Collector

 12 ft long, 10.5 ft wide, 5 ft high 

Dimensions of Dis-Assembled Collector - Transport Mode 

(divides into two sections of similar size) 

12 ft long, 5 ft wide, 5 ft tall 

Covered Area Producing Shade 

138 sq ft 

Two Identical Ramps 

~300 angle, 10.5 ft wide, 3 ft long 

(composed of 32 EF:16 plates per ramp) 

Portion of Ramp Below Water Level 

~1/3 or 1 ft 

Portion of Ramp Above Water Level 

~2/3 or 2 ft 

Typical Elver Climb Time from Out of Water to Ramp Crest 

< 30 seconds 

Water Flow

Water Pump 

~124 gal/min (7.8 liters/sec) 

Flow rate across each EF-16 plate 1.1-1.6 gal/min (0.07-0.1 l/s) 

Power Requirements

Water Pump 

Single Phase

110V, 13A, ~28 lb 

Revolutionary Elver Upstream Floating Collector Design Components

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Two pontoon floating structures allow versatility of placement in the waterway where elver congregate. 

The floating design enables standardization of attraction flow and climbing distance regardless of river fluctuations. Easily removed from waterway for winter storage, extending product life. 


Redirects river flow creating a central channel through the collector that facilitates elver ramp approach by creating slow-moving backwater over which supplemental directed attraction flow is provided. 


Multiple flow dispersal points (blue arrows to right) Total attraction flow of ~66 gal/min directed down into the central channel. Water flow positioned at the top of each climbing substrate ramps at 25 gal/min facilitating migration attraction of elver up the ramp. 


The collector is fully covered from pontoon to pontoon creating a large, 138 square foot shadowed area. Elver are attracted to the dark environment. Successful elver collection in both day and night time hours have been documented. The cover also minimizes predation. 


Positioned perpendicular to river flow, the elver do not need to overcome the river flow rate to begin climbing up the ramp. The ramp length is standardized to a short distance of ~3 feet, reducing climb time, stress and energy reserve use required to climb and pass over the ramp crest. Two ramps, one on each side of the collector, with a width of 10 feet, extends the opportunity for the elver to locate the ramp ~16 times, increasing use efficiency. 


EF:16 is a proprietary climbing substrate designed for increased ease for elver navigating a climb, providing features that facilitate rest during the climb and variation of flow stream. 


Elver pass over the ramp crest into an enclosed collection channel. The elver flow with the small stream through the channel and into the collection trap positioned underwater. The trap is perforated to allow continual fresh river water flow through the trap. The collection container is subsequently manually emptied and elver transported to release locations. 

Switchback Elver Trap

Switchback™ Design Features
Additional Features
Water Flow and Power Requirements
Water Flow and 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) 


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 

Switchback™ 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 

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  

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EF-16 Climbing Substrate

EF-16™ Climbing Substrate Features
Working with EF-16™
EF-16™ Climbing Substrate Features

Vacuum molded plastic tiles

Corrosion resistant and durable

Overlapping, interlocking feature

        Tapered, stud structures facilitate a variable depth stream flow path, velocity adjustment obstacles, and rest            structures for climbing elvers

Design optimized to accommodate large range of elver sizes

Secured to elver trap ramps via rivets or screws 

Definition original tile & end tile

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).

Dimensions of EF-16™ tiles: o 490 x 200 x 40 mm
Working with EF-16™

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

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 at additional cost, under a signed contract commitment.

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