By Susan Matheny
Paul Jensen, who for decades flew the air streams as a crop spraying pilot, saw a correlation between airflow and waterflow, which helped lead to his invention of a vastly improved fish bypass system for dams.
“I’ve been in the spray business for 30 years and have also done design work for companies in the agricultural field for years,” said the 66-year-old Jensen.
With a background in chemistry and mechanical engineering, Jensen said his idea was prompted by consulting work he was doing in 2003 for the Concep Co. in Bend, an offshoot of Bend Research Co.
They were having a problem developing a pheromone spray applicator to go on cotton cultivators. The trouble was that the 1 millimeter chemical-filled “beads” in the spray were not mixing correctly, because they were lighter than water.
“I added a gel to hold the beads in suspension, so they could flow through at a low volume,” he said.
“That work led to the fish passage idea, using the same principles,” he added.
He spent time researching the problems of fish migrating downstream and learned two important things.
“I found smolts (young fish) migrate in the top 20 feet of a river, like the Columbia, and they travel close to shore. That was an advantage, because then I knew where to capture the fish,” he said.
Jensen Bypass System
In developing his system, Jensen noted that when fish traveling downriver get to a dam, they swim back and forth looking for a place to continue downstream. They swim deeper as they search, and eventually go into a power tunnel that leads to a turbine.
“Fish don’t like to enter a black hole, and only enter out of desperation,” he said.
Some dams have an in-line turbine screen that channels fish up away from the power turbine and into a pipe that carries them around the dam.
“But I found that some fish go under the in-line screen to the turbine, which is revolving three times per second. The fish get the bends and it kills them — which is the problem,” Jensen said.
With an in-line screening system, it’s estimated that 10 percent of the migrating fish are lost at each dam, he noted.
“My system sits in the forebay, or pool behind the dam, not in the turbine channel. I propose a large 10- by 100-foot funnel, supported by buoys, that’s made out of a clear material so the fish won’t realize they are going into a black hole. By the time they’re pulled into my system, they’re going too fast to swim out,” Jensen explained.
In the Jensen bypass, the fish are screened out and funneled below the dam, while the water goes into the turbine power tunnel. He’s not releasing further details about the system until his patents are finalized.
To test his idea, in 2003 he built a small model out of two-inch PVC pipe and ran experiments.
“I used guppies and did experiments 42 times with zero injury to the fish and 100 percent separation (of fish diverted out of the main flow),” Jensen said.
He had done a patent search and found nothing like his system. Then in 2007, the New Zealand Fish and Wildlife Department did a study on every fish separating system worldwide that they could find. “There was nothing close to what I’ve made,” he said.
With the successful test of his idea, which was a much more practical approach to the fish bypass problem, Jensen contacted the National Marine Fisheries Service to see what the next steps were to gain their approval for use.
But the project was put on hold for a few years, due to a lawsuit between the city of Madras and Jensen over a nonrenewal of the lease for his aerial spraying business, which drained away any funds he had for experimentation.
Things picked up again in 2008, when the National Marine Fisheries Service gave him an outline of what would be needed for a bigger model to prove his idea would work in a river.
Jensen contacted and received help from Deschutes Valley Water District, which was exploring options for an efficient downstream fish passage system for its Opal Springs hydro facility.
“Dechutes Valley Water was encouraging towards finding a solution to the fish problem. They were wonderful to deal with and were a major help,” he said.
DVWD agreed to let Jensen test his system at its Opal Springs hydro dam. “For the first test, I made pseudo fish out of weighted dowels, then I used live fish. The Oregon Department of Fish and Wildlife allowed me to use 20 fingerling fish from the Opal Springs Hatchery,” he said.
Don Ratliff, head biologist for Portland General Electric on the Round Butte Dam fish bypass equipment, encouraged him and helped him get permission to use the hatchery fish.
Three trials were run Aug. 18, 24, and 30 at Opal Springs, with the fingerlings being released, then netted as they exited Jensen’s bypass system.
Only one fish died, and that was because it got trapped on the side of the exit net. They didn’t see it and set the pipe down on the fish and killed it when they were removing the funnel.
“But that didn’t count because the fish was healthy when it went through the system,” Jensen said.
The small-scale Opal Springs tests were successful, but would his bypass work as well in a river-sized model?
“It won’t make any difference. The laws of physics are true on a small or a planetary scale. You will get the same results,” Jensen stated.
A few weeks ago, he typed up a report with photos and sent copies to nine organizations including the National Marine Fisheries Service, National Oceanic and Atmospheric Association, ODFW, and Pacific Power to generate interest.
“Paul has quite a unique and promising concept that needs to be looked at closely by federal fish agencies. It has some real-life applications,” said Don Ratliff.
It typically takes eight years between a product concept and the marketing of the product in the U.S., he said, but thinks his chances are good.
“This is a unique approach that solves almost all of the problems with downstream migration: 1) It can capture fish where they are. 2) There’s no risk of descaling fish. (If fish bump into something, their slime comes off, which protects them from bacteria). 3) Fish remained healthy. Test fish were kept two weeks before being returned to the hatchery and showed no indication of any problems,” he observed.
With 3,600 small dams like Opal Springs in Oregon, and large river dams on the Columbia, McKenzie, and Santiam rivers, the Jensen Smolt Bypass System could have a big market.
“There could potentially be a worldwide market, but I don’t want to get too excited yet,” Jensen said.
“I look at it and think `Why hasn’t this been done before?’ It’s fairly simple, but it’s complex in that you have to do certain things in order,” Jensen said of his invention.