Electric fish barriersNEPTUN

1. “Informational” electric field - electric energy absorbed to scare not to stun the fish.

2. Random alterations – prevent adaptation to constant electric field.

3. Ease of installation 4. Size flexibility5. Resilience and robustness5. Resistance to low temperature (icing).6. Low energy consumption (solar panels for

small barriers)7. Low maintenance costs.

Key Design Features

Features That Set Neptun ApartNon-linear distribution of the electric field in water, contrast to classical barriers where the electric field intensity in the area between the electrodes is constant regardless of fish location (next slide).  Intensity of the electric field

positive electrodes - close to zero negative electrodes maximum.

 Adjustable DC pulse parameters:

• amplitude, • pulse duration, • intervals between the pulses • number of pulses in a packet.

NEPTUN technology

U = E x L where:U – voltage accumulating on the fish’s body E – current intensityL – fish’s length1 – average gradient E at all sections of the electric barrier (U1)2 - average gradient E at all sections of the electric-electronic barrier (U2)3 – direction of fish movement

B=D classic electric barrierC>A NEPTUN technology

Gradient of the electric field :classic electric barrier vs NEPTUN technology

=> The closer the fish the stronger the field !!

U = E x L where:U – voltage accumulating on the fish’s body E – current intensityL – fish’s length1 – average gradient E at all sections of the electric barrier (U1)2 - average gradient E at all sections of the electric-electronic barrier (U2)3 – direction of fish movement

A>B>C classic electric barrierA<B<C NEPTUN technology

Gradient of the electric field :classic electric barrier vs NEPTUN technology

=> Size matters but distance matters more!! Selectivity possible.

Simplified block diagram of the NEPTUN device

Example of the single electrode

Electrodes are attached to a line along the bottom (next slide)and have floats on top to hold them in vertical positionElectrodes are flexible and allow passage of debris, etc.Ideally, a concrete floor is used to anchor the electrodes, but not necessarily

Rope to which the electrodes are attached is mounted to the bottom

Pictorial diagram of electrode spacing

Lab test

The electronic equipment of the control and power supply systems – open switchbox, the weir in Krzywaniec, Bóbr River.

Technical parameters• length : 93 m• length of a single electrode: 2.2 m for electrodes

with positive and negative polarisation• electrodes: acid resistant steel A4• electrodes mounting : anchored to a concrete block

at the bottom of the reservoir • power supply for the control and power supply

system: 3-phase, through a separate transformer, (1-phase possible)

• average power intake : 0.43-0.45 KWh

to Hydropower Plant

ElectrodesNegative polarization (-)

ElectrodesPositive polarization (+)

Electronics

Installation on the weir in Krzywaniec, Bóbr River.

View of marker buoys of some negative electrodes

Rzeszów

Szczerców

Integrated

Insert photograph of example site?

Integrated

Insert photograph of example site?Correct spelling to symmetrical - IE can not edit due to the information being inserted as a picture.

Integrated

Insert photograph of example site?

Integrated

Insert photograph of example site?Also, can this type be modified to guide sea lamprey into traps? If so, include this information in the slide.

Acoustical monitoring of fish at an electric barrier –NEPTUN EY 500 split beam echo-sounder with the transducer directed horizontally.

Krzywaniec reservoir / Dychow complex hydraulic engineering, on the river Bobr

Stationary measurements powered and not powered (next two slides)

Barrier off…presence of fish between electrodes detected by hi-res sonar

Fish are everywhere; N=283, scanned for 4 minutes

Barrier on for 20 minpresence of fish between electrodes detected by hi-res sonar

Few fish attempting to cross the field; N=10; scanned for 4 minutes

Minimum Technical parameters required for design

Design criteria:• Site map showing intake, outlet of turbines, fish-passes; • Depth and electric conductivity of water• Substrate• Mean cross sectional velocity (no greater than 0.5 m/s)• Available power supply (1- or 3-phase)

Neptun Benefits

• Increasing field intensity• Electric field depth-independent • Electric field can be depth-dependent• Low power consumption (solar for small

barriers)• Low operation and maintenance costs• Safer• Electricity does not disperse into the ground• No depth limitation• …

Neptun Benefits

• No debris interference• Does not affect navigation• Safety and operation logging• Remote control• Can be installed anywhere (new or retrofit)• Many applications• Low purchase and installation costs• More humane