Use of large half-duplex PIT tag antennas to evaluate entrainment

Expanding from Creek to Hydroelectric Diversion Facilities –Construction and in situ evaluation of large half-duplex PIT tag antennas

to evaluate fish entrainment at high velocity water diversions

Presented by: Doug Demko

Contributing Scientists: Gabriel Kopp, Matt Peterson, Dana Lee

What is PIT Technology

Uses and Advantages Unique individual code

Long life, no battery

Small size

Cost effective

Minimal biological impacts

Full Duplex Monitor greater density of tags at one time

Half DuplexLower cost

Greater read range

More resilient to interference

12 mm

PIT System Components

Antenna

Power Supply

Control Unit

Data LoggerOregon RFID

Thermoelectric Generator Control Unit & Data Logger

Antenna

Typical PIT Field Research Antenna Deployments

Small Scale

Low Flow

Constrained Flow to Meet Small Detection Area

Typical PIT Field Research Antenna Deployments

Study Objectives

Monitor O. mykiss entrainment at hydroelectric diversion facilities for over one year

All trout ≥ 60 mm tagged (O. mykiss n=536, S. trutta n=2)

60-129 mm fish (36%) = 12 mm tag

130 mm and larger (64%) = 23 mm tag

Estimate entrainment based on known number of potentially vulnerable fish with PIT tags

Study Area

Small tributaries in Northern Sierra Nevada Mountains

Large seasonal fluctuations in flow

Study Area (cont’d)

Large diversion tunnels

4.6 m x 3.7 m4.4 m x 4.4 m

High flows≤ 24.4 cms(≤ 845 cfs)≤ 31.1 cms(≤ 1072cfs)

High Velocity Measured max = 1.5 m/sCalculated max = 3.7 m/s

Fabrication

Three antenna stacked array

Hydrodynamic “wing” designRigid, strong, and durable

Multiple layers of woven fiberglass mat

Over 1400 hours spent fabricating both arrays ($125,000 USD)

PIT detection wire embedded in fiberglass during fabrication

Antenna Fabrication

Layers of Fiberglass Wiring Added

Sanding Between LayersFiberglass Shell

Fabrication (cont’d)

Operation

99% of all diverted flows monitored for entrained fish

Antennas and electronics highly reliable

Minimal required maintenance

Manually re-tune antennas

Easily removable -allowing built up debris to wash through system

Operation

Efficiency tests for 23 mm tag were 100% at both diversions

12 mm tag efficiency above target of 80%

Flow in Oregon Creek Diversion Tunnel

Maximum discharge in Oregon Creek Diversion Tunnel was 31.1 metersᶾ/sec (1072 cfs)

Average flow was 4.1 metersᶾ/sec (144.2 cfs) over entire study period

0

5

10

15

20

25

30

35M

eter

sᶾ/s

eco

nd

Entrainment Results

A total of 220 detection events representing 58 unique fish observations

Many fish were detected multiple times, indicative of milling behavior

Few individual fish detected at both diversion tunnels

Entrainment rate relatively low

Fabrication Results

Innovative and successful design, application, and deployment of half-duplex antenna technology

Large half-duplex fiberglass antennas can be constructed to withstand high flows/velocities at large water diversions

Detection efficiencies (average greater than 90%) and reliability high enough to effectively evaluate entrainment

Thank You

Contact:dougdemko@fishbio.com

Questions