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Months after harmful drop in stream flows, fly fishers cast for answers in Rapid Creek

Rapid Creek with healthier flows last week at Cliffside Park
Kevin Woster
Rapid Creek with healthier flows last week at Cliffside Park

First, there is some good news about Rapid Creek. Macy Lundstrom had her hands full of it the other day below Pactola Dam.

“I caught some nice fish up there,” Lundstrom said Monday afternoon, after I interrupted her work labeling flies at the Dakota Angler & Outfitter fly shop here in Rapid City. “I’ve got some pictures, if you want to see.”

Me, see trout pictures? Oh, yeah. I think could handle that. And, oh, they were beautiful fish — solid, healthy looking wild brown trout, running from 17 to 20 inches long.

Lundstrom, a 19-year-old fishing guide for the fly shop, caught the trout a couple of weeks ago while fishing Rapid Creek in the Pactola Basin just below Pactola Dam. She saw good numbers of fish in some parts of the creek up there, but fewer than normal in others.

Macy Lundstrom with a brown trout caught recently from Rapid Creek below Pactola Dam
Macy Lundstrom
Courtesy Photo
Macy Lundstrom with a brown trout caught recently from Rapid Creek below Pactola Dam

That might just mean the “missing” trout were downstream in deeper pools, which Lundstrom suspects is the case. Or it might mean something more troubling. Time will tell.

More than five months after an unplanned repair project on Pactola Dam led to sharply reduced discharges into Rapid Creek, it is still unclear how much damage was done to the wild brown trout population from the dam down through Rapid City.

And with scientifically based stream survey work by the state Game, Fish & Parks Department still months away, unscientific observation is about the only survey work going on.

With legs encased in GORE-TEX, fly rods in hand and hearts filled with cautious hope, fly fishers who know and love the creek are wading into a spring that will offer some idea of how much damage was done by low stream flows early last winter.

It came at a tough time for trout and their eggs

It was a terrible time for a sharp drop in flows. Unlike spring-spawning rainbow trout, brown trout lay their eggs in mid-to-late fall, depositing them in gravelly sections of stream. The female browns prepare spawning beds, or redds, by cleaning silt from the gravel or small rocks with their tails. Then they lay the eggs, which male brown trout fertilize and defend.

There is no defense, however, against low water. Not for trout.

The eggs need consistent stream flows and plenty of cold, well-oxygenated water to survive. Many stretches of Rapid Creek between Pactola Dam and Rapid City lost those needed conditions for about a week in early December.

During the low flow period in early December, Karl Stephenson took this photo of nearly de-watered Rapid Creek at Cliffside Park in western Rapid City
Courtesy Photo
Karl Stephenson
During the low flow period in early December, Karl Stephenson took this photo of nearly de-watered Rapid Creek at Cliffside Park in western Rapid City

A week is a long time for a trout.

“Those low flows coincided with when the fish were still spawning or had just finished,” said Hans Stephenson, who owns and operates Dakota Angler & Outfitter with his brother, Karl. “And some of the spawning areas were among the first to be exposed.”

A late November inspection of two release gates at the dam detected a problem with “cavitation,” or a build up of pressure in specific areas when water hits cracks or bumps in concrete and starts to damage the structure. The damaged gate had to be shut for repair. And the second gate had to be closed in order for work to be done on the first.

Officials for the federal Bureau of Reclamation later said that it was important to do the repairs quickly. Which makes sense. Dams with structural issues are not to be ignored.

But in that haste, the bureau failed to notify GF&P of the coming drop in flows. So there was no discussion of potential impacts or of potential ways to mitigate damage to trout. And when the water dropped, it was a jarring surprise to fly fishers and GF$P.

Then the project took longer than expected when certain repair materials needed to be ordered.

The gates had been discharging more than 40 cubic feet of water per second (cfs) before they were closed. A diversion channel that could have provided a discharge of 18 cfs couldn’t be used because it would have released water near the work zone. So a lower-capacity diversion pipe was used, initially discharging at about 8 cfs and then stabilizing at slightly less than 12 cfs.

A dry stretch of spawning bed and “wrinkled up little trout eggs”

The reduced flow was soon noticed by people who fish the creek. And they started to look for signs of trouble for trout. Dave Hanna, president of the Black Hills Fly Fishers, told the Rapid City Journal that he saw “wrinkled up little trout eggs” in exposed parts of the creek bed below Pactola Dam during those low flows.

And nothing got better closer to Rapid City. Even at a release of 12 cfs, the creek didn’t carry that level of flow for very far downstream from the discharge pipe. As it wanders its way toward Rapid City, Rapid Creek loses part of its flow to natural limestone drop zones in the stream bed.

And with ice forming on the creek, particularly in shaded areas under canyon walls, even more of the limited flow was lost.

By the time the creek reached Cliffside Park on the west edge of Rapid City, it was a trickle. A stream gauge above Canyon Lake registered 6 cfs at one point, then 1 cfs at another.

Karl Stephenson captured the sad state of creek affairs at Cliffside in a photo he put on the fly shop website. Word continued to spread within the fly fishing community in Rapid City, and to Game, Fish & Parks.

GF&P Fisheries Program Administrator Jake Davis offered preliminary information on the water problem to the GF&P Commission during its meeting in early December.

“So essentially in all of Rapid Creek, you’ve got one cubic foot of water (per second) moving through,” Davis said, referring to the stream-gauge reading near Canyon Lake.

Things improved somewhat farther into the city, where a few feeder creeks boost the flow of the creek. Even so, ice formation mitigated some of the benefits of the feeder streams.

The trout sought refuge in deeper pools that weren’t as deep as usual. And even those pools had their own element of risk, concentrating fish for predators such as mink and increasing the inclination of larger trout to feed on smaller ones.

Impacts on eggs, stress on adult trout

In the less-accessible stretches of creek between the dam and the city, it’s even harder to know what happened and how the fish fared. But there were some very low temperatures and some very heavy ice concentrations.

Hans Stephenson said he talked to someone who lives in the Hisega area who told him “it was the heaviest build-up of ice he’d seen in there in years.”

We know the low flows resulted in the loss of brown-trout eggs in some stretches of the creek. Dave Hanna saw some of them himself. And we know the low flows put additional stress on adult brown trout, which — especially females — were already stressed from the spawn.

Jake Davis told the GF&P Commission “those eggs are certainly going to be impacted.” As for the adult trout, he said “it does put a lot of stress on these fish.”

The long-term effects on both this year’s hatch and the adult-trout population remain to be seen. But it’s the talk of the town among fly fishers, especially those who gather at Dakota Angler & Outfitter.

Some of anglers report pretty good fishing in town. Hans Stephenson has enjoyed some of that himself this spring.

“It’s encouraging to see those adult fish in pretty good shape,” he said.

But a sampling here and there doesn’t tell the whole story.

“Honestly, I don’t know if we’ll have a clear idea until after Game, Fish & Parks does some survey work on the stream,” Stephenson said. “We all feel so strongly about it that we’d like some answers as soon as possible.”

Summer survey work could answer some questions

It could be mid-summer or later before GF&P crews do their survey work. And even then, it could be a year or two before the overall impacts are fully understood.

The middle sections of the creek from Pactola Basin down to Dark Canyon at the western edge of Rapid City are the last to get free of ice and tend to be the last to get any serious angling pressure. So the questions could linger longest there.

As he waits, Hans Stephenson hopes the experience with the low flows will lead to better planning and communication to avoid a repeat of what happened last December. Beyond that, he hopes for stream habitat work that could improve the channel depth overall, add deeper pools and create and maintain more safe escape cover and reliable habitat for trout.

Hans Stephenson of Dakota Angler & Outfitter wants better stream-flow management and habitat work in Rapid Creek
Kevin Woster
Hans Stephenson of Dakota Angler & Outfitter wants better stream-flow management and habitat work in Rapid Creek

During the last 25 years, four or five years of consistently high flows ate away at stream banks, widened the channel, reduced overall stream depth and filled in some pools.

“All of that probably exacerbated the effects of the low flows we had last winter,” Stephenson said. “I hope we can use this situation to move toward better water management in the creek, but also for habitat development.”

Meanwhile, the unofficial stream survey by the fly-fishing crew proceeds in Rapid Creek, with trout like those caught by Macy Lundstrom offering a good fight, and a bit of hope.

Click here to access the archive of Woster's past work for SDPB.