I finished my Natural History of Missouri class, and now I have more questions than when I started. That’s a good thing. Now I’m revisiting some things I observed, but never documented.
Arcadia Valley
Back in March, my friend Trey and I went to the Arcadia Valley Region to see The Mississippi Sawyers and visit the awesome trifecta of state parks and Fort Davidson Historic Site. I took a hard look at Taum Sauk for my class, but didn’t get a chance to blog about Johnson’s Shut-Ins or Elephant Rocks until now. Here are a few things I observed on March 20th and a few questions I raised.
Geology and Water
This first video is a pan from the very start of the Shut-Ins trail. You begin to see small exposed chunks of rhyolite, which hung on after sedimentary rock was worn down after years of water erosion. An interpretive sign explained that this part of the trail will someday become like its neighbor downstream, but the “changes are imperceptible to generations of visitors.” I’d like to know just how many hundreds of thousands of years it took for the main part of JSI (see below) to go from this sandbar state to what it is now. Also, let’s imagine that urban development were to rush into Arcadia Valley (ecotourism, huge influx of bluegrass fans, World’s Fair — hey, you never know). If a lot of pavement and buildings were to get built in the watershed that feeds the East Fork Black River, its water load would increase. Would increased water volume severely advance the rate of erosion? Would speed or rate of flow? Does flow rate increase with volume?
Aquatic Wildlife
This next clip takes a pan of JSI’s main drag. A video can’t do it justice. The the grandeur of the valley, the size of these rock formations, the sound of the water and its cool spray all contribute to the experience. It was pretty cold when we went, so we didn’t splash around. I wonder what kind of aquatic wildlife can handle this fast-moving water and the labyrinth of rhyolite. Fishes? Frogs? Hopefully this summer I can get back there and investigate more. I’m also curious about how many other such shut-ins there are in the state and the nation. I think one of Dr. Weaver’s books about Missouri natural wonders listed at least 20.
Vegetative Restoration
JSI isn’t just about the water. Trey and I also hiked the Scour Trail, which leads up to and follows the area that a 2005 reservoir break scoured. Look at the full-size image of this photo, and you can see the giant boulders that the water carried down to what is now the Black River Center. How many trees did this uproot, or did they all withstand the flood? How quickly did it take for those grasses to fill in around the stream? Surely, if the land were stripped to its bedrock, it would have scoured out all of the grass seeds and roots as well. I’m interested in the process of vegetative restoration.
The mystery of felled trees
These uprooted trees on the trail were more curious than the scour itself. They’re on the other side of the hill from the stream, so it seemed like it wouldn’t have been the reservoir break. We also noticed a lot of trees down along the highway. I felt really vexed about what caused this, but I’ve found the answer: it was the May 2009 Southern Midwest Derecho! Click the link; it’s fascinating. Basically this area was part of a 15-hour “inland hurricane” that struck three states and induced winds up to 106 miles per hour. Holy cow! Mystery solved!
Tina Casagrand
