As weather patterns trend wetter in central Pa., how could fish and streams be affected?

Phil Dress and Glen Steiner, both from Allentown, and Gary Mitchell, of Lewistown, drove to Centre County on April 11 to help the Fish and Boat Commission stock Bald Eagle Creek with rainbow trout, and to do some fishing of their own in Spring Creek.

The trio said they were excited for trout season to begin that weekend, as the record rainfall last summer and into the fall kept them from getting out on the stream as much as they would have liked.

“We like when the water is a little lower and clearer, and the fish are a little more active on the surface,” Dress said.

The higher-than-usual water levels, faster currents and muddy banks made conditions more difficult for wade fishermen, like himself, he said.

While high and fast waters were a deterrent for some anglers, it was a welcome challenge for others.

Dave Fello, of Walker Township, prefers fishing in higher waters.

“It makes it more difficult for some of the guys to catch fish, so there’s fish in the creek longer into the season,” Fello, who frequents Bald Eagle and Penns creeks, said. “It scatters the fish more.”

While anglers debate whether more rain is good or bad for fishing, weather patterns are showing it might be something they’ll need to get used to.

Wet weather in the forecast for the foreseeable future

Although 2018, with a record 63.75 inches recorded at the National Weather Service’s State College station, may have been an outlier, data are showing an overall trend toward wetter weather patterns in central Pennsylvania, Steve Seman, Penn State assistant teaching professor of Meteorology and Atmospheric Science, said.

“Taking the ‘long view’ on a shift toward more wetness in central Pennsylvania, we average about 3.5 inches of rain more per year than we did when reliable weather records began in the region (1890s),” he said. “To put that into perspective, that’s about an additional month’s worth of rain per year, on average, compared to the late 1800s.”

State College’s previous annual precipitation record — 59.3 inches in 1996 — shattered the 1994 record before it by more than 10 inches. Since then, there have been four more years — 2003, 2004, 2011 and 2018 — that have had more than 50 inches of rain, NWS records show.

This matches a broader trend across the northeastern U.S. and Middle Atlantic, Seman said, both areas that have seen an increase in the frequency of heavy rain events in the past 50-70 years.

“It seems that rainfall in central Pennsylvania has become both more frequent and heavier,” Seman said. “The average number of days with measurable rainfall per year has increased since the 1890s, as have the number of days with at least 1 and 2 inches of rain.”

These trends, Seman said, are what should be expected as the world warms. A warmer environment will favor more evaporation from water and soil, increasing the amount of water vapor in the atmosphere, making more moisture available when it rains, he said.

Volunteers help the Pennsylvania Boat and Fish Commission to stock rainbow trout in Bald Eagle Creek on Thursday, April 11, 2019. Abby Drey

With more rain comes increased erosion

As weather patterns in central Pennsylvania are trending wetter, stream health — as well as the health of the fish within the stream — may be affected.

“Excessive rainfall and heavy rain events Centre County experienced in 2018 resulted in soil erosion, occurring on upland landscapes and along stream banks,” Justin Kozak, watershed specialist with the Centre County Conservation District, said. “Upland soil saturation, coupled with rainfall rates greater than the rate at which water could infiltrate into the soil, led to surface runoff carrying soil downslope to nearby streams on landscapes throughout the region.”

Streambank erosion was also prominent in 2018, Kozak said.

“During times of excessive precipitation, when the stream water level exceeds bankful height, more and faster-moving water is available to carry a larger sediment load,” he said. “This results in the soil and rock of banks along streams breaking loose and being transported downstream.”

While erosion and sediment transport are both part of the natural process of stream systems, Kozak said, excessive sediment in streams caused by more frequent and heavier rainfalls can lead to the degradation of habitat for aquatic organisms, including trout spawning habitat and habitat for aquatic insects — a primary food source for trout.

Most fish require clean gravel to spawn on, according to Shannon White, a Penn State Ph.D. candidate studying the adaptive capacity of coldwater fish.

“If there’s a lot of erosion, the water gets very turbid or muddy. That could be an immediate issue where the sediment erodes or scrapes away at their gills,” she said. “But then, long term, if that sediment sits in streams, then the fish can’t spawn as well. Or even if they try to spawn, it will kind of choke the eggs because they can’t get oxygen in the water if it’s full and clogged with sediment.“

The Pennsylvania Boat and Fish Commission stocked 2500 rainbow trout in Bald Eagle Creek on April 11. Abby Drey

How increased rainfall can affect Pennsylvania fish populations

Another issue for spawning and egg and juvenile fish survival is high-flow rainfall events — which Centre County saw several of last year — White said. In the springtime, the biggest threat is to small mouth bass.

“For them, a really heavy rain event has the potential to completely destroy a nest,” she said. “If you’re talking about bass, you’re talking about the potential for reduced reproduction, or at least reduced reproduction for those eggs.”

But even more devastating is the potential for entire populations of fish to collapse, White said. It’s a reality that could occur at a higher rate as catastrophic flooding events become more and more frequent, something that White has observed in the Loyalsock Creek in Lycoming County, where she conducts much of her research.

Hurricane Irene and Tropical Storm Lee brought historic flooding to Loyalsock Creek in 2011, as waters exceeded flood stage by nearly 8 feet, according to the NWS, the worst flooding to hit the area to date.

When White began her research around 2016, the creek experienced another major flooding event. Although this one wasn’t as bad as the 2011 flood, she observed the complete collapse of brook trout populations, where there would go from being 100 fish at a site to two.

While fish are typically pretty resilient and able to recover from such flood events — and can even benefit by the creation of new habitat — White said that the increased frequency of these “50-year” or “100-year” floods is making that recovery more difficult.

“It’s when we have an increased occurrence of these really, really big flood events that we start seeing more long-term issues or more long-term effects on the populations,” White said. “This fish populations can usually recover, but it may take a few years. But if they’ve recovered, gotten a little unstable and this happens again, and that kind of pattern continues to happen — which we are expecting with climate change — then eventually they can’t recover from it so much.”

Once a fish population initially recovers, it typically has decreased genetic diversity, White said, making it more susceptible to future disturbances or disease.

“That’s the kind of stuff that’s hard to see,” White said. “The population might be large, but it could be kind of like a sitting duck, in terms of it only takes one maybe fairly small disturbance for it to completely wash out again.”

That point, White said, is when the fish populations — particularly brook trout, the focus of her research — may not come back.

Another flooding-related issue for fish, White said, is increased stream temperatures that can result from floodwaters running off pavement in more developed watersheds — particularly in the summer.

Pennsylvania’s state fish — the brook trout — is one of the more susceptible fish populations to warmer water, White said. Typically preferring water temperatures in the mid-60s, all it takes is for rainfall to increase stream temperatures by a few degrees to put stress on the fish.

“When you have increased stress, it generally decreases reproduction and decreases population sizes,” she said. “Then we’re back to having decreased genetic diversity.”

Landis Wright with the Pennsylvania Boat and Fish Commission scoops rainbow trout into buckets to be stocked in Bald Eagle Creek on April 11. Abby Drey

What can landowners do to help?

The effects of runoff on streams and fish populations can be mitigated, White said, through the use of more green development practices, such as maintaining more green spaces and riparian buffers between more developed area and the water. By having a buffer, much of the sediment and pollutants can be filtered out, and the water temperature can decrease before hitting the stream.

For landowners, the state Department of Environmental Protection suggests planting a vegetated buffer of shrubs and trees along streambanks, and not mowing up to the steam’s edge. The DEP also encourages residents, regardless of proximity to streams, to implement stormwater best management practices, such as installing rain gardens, rain barrels, cisterns and dry wells, to help minimize and slow down runoff.

On the statewide scale, Gov. Tom Wolf’s Restore Pennsylvania plan, which proposes a natural gas severance tax to generate $4.5 billion over four years, according to the Governor’s Office, would include funding for flood control and prevention infrastructure, after an early August storm last year caused more than $60 million in damage to transportation infrastructure in the middle part of the state.

“Many needed projects involve streambank restoration to restore flow and prevent future erosion,” according to the plan. “Other projects will be for floodplain restoration, which allows stormwater to spread out and slow down, so it can be absorbed into the groundwater, rather than flooding over streambanks. Additional critical flood control infrastructure includes dams, levees and flood walls.”

As for right now, Chriss Brower, waterways conservation officer for the Fish and Boat Commission in Centre County, said he has not yet seen a major impact from last year’s excessive rainfall on the local fish population. Regardless of the more challenging stream conditions, he said Centre County’s waters were still heavily fished last season.

Despite the already-rainy start to this year’s trout season, Brower, himself an angler firmly in the high-water-is-better camp, is looking forward to it.

“When the water’s swelled up onto the banks, they (the fish) hit off the edge of the banks so they don’t get swept downstream, and they scatter,” he said. “It’s actually a good thing because the fish can spread out more and aren’t all in one hole. You can’t walk in and just bang, bang, bang, catch them then leave. You have to work for them.

“I like that,” he said with a laugh.

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