Nature at work
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One of my local rivers has undergone some changes solely at the hand of nature. I first floated a 7.5 mile section of the East Gallatin River in the fall of 2008. By 2014, just six years later the landscape had changed. The East is a low gradient valley stream that meanders (literally) from Bozeman to Manhattan, Montana where it meets the main stem of the Gallatin River. It may flows 4 miles for every mile west it goes.
When I first started floating this particular section of the East Gallatin River near Belgrade, MT, there was on 90 degree corner at which it sounded like there was an incoming creek under the willows lining the bank. The river is lined with willows and grass and when you are on or in the river, you can’t tell how close or far the next bend is to your current position.
The aerial (probably 2010) shows the place I will talk about. The high water we had in 2010 broke through the bank at the bend. In the 2010 season, this opening was slightly wider than a canoe. Between 2011 and 2013, the opening grew at bit, but the 2-3 foot differential between the upper and lower river remained. The approximate ¼ mile oxbow retained good flow and fishing throughout the low water periods. The pool and deadfall at the turn were a hangout for big browns and rainbows.
Here’s some photos I found to illustrate.
(Probably 2011)
(Probably 2011)
http://vid527.photobucket.com/albums/cc354/Bozeman_Mike/East%20Gallatin%202012/PB020449.mp4
(Very short video in 2012)
(2012)
Friday, I fished this section of the river for the first time since runoff. When I approached the pool below the breakthrough I knew something had changed drastically. The river below the breakthrough pool wasn’t the same. There were massive amounts of fresh gravel in places that were deep before. As I looked upstream at the breakthrough there was no long any significant gradient drop and the river coming in from the oxbow was stagnant. There appeared to be a huge sandbar just upstream from the breakthrough.
I could now paddle through the break upstream. When I reached the upstream side of the break, this is what I saw.
The entire up stream section of the oxbow has been dewatered and filled with 3-4 feet of gravel and silt. Runoff on the river reached over 1000cfs (12X normal) several times in 30 days this season causing the catastrophic change in this section of the river. I didn’t explore the oxbow this trip, but will next time to see what has happened around the bend. I hope to keep documenting with photo how this part of the river changes over the coming years. But the spot where I caught this guy last spring (2013) is now gone forever.
Nature at work.Strategy without Tactics is a Slow Route to Victory, Tactics without Strategy is the Noise Before Defeat - Sun Tzu
That is cool. Thanks for sharing that Mike. Of course the trout are all still there; they’ve just moved around. Wonder what will happen on that Oxbow with respect to the landowner? He looks to have gained a lot of acreage, or at least functionally so.
Same thing happened in my favorite section of a Wyoming river. High water in 2010 stacked gravel in such a way that it stopped flow into a side channel. It held some of the biggest fish and nobody fished it because it was hard to access.
Now it’s frog water.
Fascinating stuff Mike. Thanks for sharing this.
I thought the same as Zach….landowner gained some usable acreage but the fisherman in me wants the river channel preserved. I found myself thinking…..if it were my land….I would have attempted to block the break and keep the trout water. 🙂
I see this quite a bit in AK and in Yellowstone. Mother Nature has a reason I assume.
Wonder what will happen on that Oxbow with respect to the landowner? He looks to have gained a lot of acreage, or at least functionally so.
Generally these Oxbows continue to flood during high water and remain swampy through the summer, so little useful land is reclaimed. The image below is an oxbow on the same river that has fully matured. It was this way in 2004 the first time I saw it, so I don’t know when the breakthrough occurred. Might have been a 100 years ago. You’ll note that the upstream section that first filled with silt and gravel has reclaimed itself with willows and grass while the downstream section remains wetland. It will be interesting to see how fast the new oxbow changes.
Strategy without Tactics is a Slow Route to Victory, Tactics without Strategy is the Noise Before Defeat - Sun Tzu
It is interesting to see nature at work. I was raised around the Mississippi River and, as big as it is, it was constantly changing. I frequented a lot of lakes that were originally part of the river. Once I moved to Florida, I noticed the same thing. Tides were constantly moving things around and storms could completely change the bottom. Sand bars would move, passes would fill and channels would shift. At least it makes it more interesting every time I go out.
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