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
