Tuesday, June 29, 2010
But I like this work a lot. Plus it has a flying unicorn in it. As always here, click on the image for a larger version.
This comes from the login page for Vimeo, a wonderful site that, unlike YouTube, doesn't allow commercial use, and is full of high quality (both in resolution and content) stuff.
Like video of Beth Pratt-Sitaula (a collaborator of ours) talking about Nepal and other cool things, like how she gained a spouse working there!
This is a very cool composition, with a wonderful sense of great void below and beyond a happy green scene. The road leading off a cliff tells us the artist means to be not only geomorphically incorrect. Maybe a fourth wall thing?
We do see a meandering river and a beach just upstream of a waterfall. Possible? The hydraulic transition over the waterfall is not very good (too sharp). But notice how the road is straight and the stream picks up sinuosity before they plunge off the Columbusian edge of the earth!
Sunday, June 27, 2010
Imagine it's March, late in the season for planting rooted seedling trees in the Midwest. You see hundreds of #2 pencil-sized twigs, each with a few pitiful roots on one end, laying in the sun on a stream restoration site in suburban St. Louis. It's oddly hot with air temps in the high 80's.
Seeing this as I supervised the construction of a project I designed, I insisted the contractor overplant. We put those seedlings in the ground ( in the design you see here, a composite revetment, planting is very easy) not expecting they'd make it.
Most of those pitiful little pencils grew into big shrubs. They were buttonbush, Cephalanthus occidentalis. Big USDA site here.
My BS is in forestry and I've seen many thousands of trees go into the ground; buttonbush breaks all the rules. As a bioengineering plant is seems to survive anything.
For urban bioengineering (using plants in stream management/stabilization) it's a perfect plant. It tends to get pushed aside by taller woodies in time, but that's OK, it thrives in both very wet and dry conditions, high and low on a streambank, and can tolerate shade. It has a dense fibrous root system that strengthens bank surfaces.
Most of my experience with buttonbush is in the St. Louis area, where streambanks are pretty welcoming to plants--most are loess-derived, and the creeks are polluted and full of nutrients.
But I've seen this species thrive on fairly dry sites, and also in standing water, which it does in the Cache River wetlands in southern Illinois, notably in "Buttonbush Swamp," which is very precisely named! And the plant's range is huge; last image is a USDA range map.
We grow a few near our house. Seeing this one in bloom today (top photo), I was inspired to write this. I should note that it looks very much like dogwood when not in bloom, with opposite leaves and very similar leaf structure. I have a hard time telling the young plants apart.
Here's another site on buttonbush.
Tuesday, June 22, 2010
I call them geomorphically incorrect.
This example is a stunning painting by Amy Chehore. I love it. It's clearly surreal, we don't expect realistic representation of landforms.
But it's fun to look at a work like this and ask "what's wrong with the geomorphology?" I'm sure you can find a few things, from the boulder (assuming this is a stream and not a lake) on which the banjo player sits to the shape of the scarps behind her.
You could write a nice essay on how the landforms and fluvial features in this painting are impossible or very unlikely (assuming they were formed on Earth, etc.) And also about why and how the artist chose to use those features, but I know nothing about that!
And it's great fun to look at lesser works meant to be representational and figure out whether they were painted from reality or made up. I can do it almost instantly, maybe from years of experience, I'm not sure. That's part of the mystery and fun.
Is it possible to have twin waterfalls on both sides of a lake like this? Why not?
And this one (an excerpt from a larger drawing) is famous, from a 1970's rock album. Of course those zig zag meanders are unlikely, but what else is wrong?
View Big Creek, Current River in a larger map
I've spent many years looking at bed material size in the Missouri/Arkansas Ozarks, but know little about how that relates to particle lithology, and haven't seen anything in the literature.
Last week I looked at this site on Big Creek north of Eminence, Missouri.
Surficial rock in the watershed is primarily carbonates and sandstones.
Drainage area at the site is about 18 square miles. Channel slope is 0.003, or 17 feet per mile. There is a narrow but well developed floodplain. As with most Ozark watersheds, there's a history of extreme disturbance on either side of 1900: clearcutting followed by overgrazing, free range hogs; riparian forest clearing and overgrazing in the last 75 years.
Most of the bed materials come from the Gasconade dolomite and Roubideax Formations.
These questions could have huge importance for studying bedload transport rates in the Ozarks with the aim of understanding the impacts of instream gravel mining. And I've seen no analysis of them in the literature.
Click on the photos for larger versions.
Here's what I see:
Though bedrock is dominantly carbonate rock, I see large particles only in cases of extreme disturbance (e.g., urban areas). Sometimes I see well rounded carbondates, but they're never very large ( bigger than fine gravel). Lithology is dominated by chert, which is well rounded only when the particles are small, less than about 80mm.
When there are sandstones in the watershed, particles are usually well rounded, though sometimes brick-shaped with well rounded corners.
At this site, D50 is about 50mm.
Some hypotheses (sedimentologists, maybe this is obvious for you, help a brother out):
1. Though these streams have suffered serious instability over the last 100 years, and bedload transport is clearly very high (this site was seriously disturbed by a county road crew, and rearranged itself over just a couple of floods), most particles above, say, 30mm, don't move downstream that much. They are pounded and ground down by smaller stuff. I picture a series of washing machines; the particles might move a bit during big floods, but most of their active weathering might take place in a small reach of stream as they are abraded by smaller particles.
2. Of course there's storage; the particles might lay dormant for centuries in the floodplain. Maybe this is why so few/small carbonate clasts? They're eaten up by chemical weathering. This could take place even in the streambed. This is another dating method, though, right?
3. Density plays a role, perhaps; maybe sandstones are less dense than cherts, and thus move more, and are thus more likely to take on well rounded, oval shapes?
4. Sandstones are more mechanically homogenous and thus round evenly, while cherts are chemical/physically diverse (within a clast) and thus round unevenly. Often you see holes in these particles, and color-wise they are very diverse, even within a particle.
What do you think?
Sunday, June 20, 2010
I'm always surprised how few geomorph types know the Current River in the Missouri Ozarks.
Kate and I are finishing a short working trip there.
This photo shows me with a project I designed in 1994 at Big Spring. This National Park Service site has a rich history, including old CCC buildings (and very cool, rentable CCC-built cabins). In the late 1980’s the Army Corps installed a massive gabion project to repair a bank blowout that threatened both Big Spring and historic structures. The hydraulically smooth, hard, gabion structure caused serious bank instability downstream (no surprise).
And this is what we fixed. Can’t see the restoration project behind me? Looks like a mass of sycamore trees? Good!
The gabions are now starting to corrode and come apart. Our bioengineered project including tree planting, degradable geotextiles, and carefully sized limestone rock (now weathered so it looks natural) should be good for geologic/ecologic time.
The watershed is mostly karst and the river's fed by many springs, some of them huge, all of them interesting. The NPS holds property and easements on both sides of the river for over 100 miles. You can canoe for days, enjoying beautiful clear water and camping anywhere you like on the sandy, mostly bug-free bars. The aquatic and terrestrial ecosystems are amazing. So is the geomorphology, which has been extensively studied by Robb Jacobson of the USGS, though much remains to learn. Robb came to Missouri in the early 1990’s after I wrangled funding from my superiors at the Missouri Department of Conservation for a study of historic channel conditions.
Water clarity can be incredible. All my underwater video (example here) was shot on the upper Current and its major tributary, the Jacks Fork. And the springs keep the water very cool even in mid summer.
Finally, a picture of me in a very happy place, snorkeling around a rootwad looking at rocks and fish, with no work to do, not even a video camera. And Kate, yesterday, doing a watercolor.
Tuesday, June 15, 2010
Last week Lily and I took an Emriver Em2 to the Ohio Stormwater Conference.It was a great meeting. We met a lot of agency folks and regional stormwater workers who have outreach missions. Anybody doing outreach immediately sees how our models attract people and catalyze information exchange.
Lily did a superb job at her first conference, had a good time I think, and we didn't drive each other batty during our roughly 24 hours in the Subaru together! She's a great companion and always entertaining, as you can see in this video.
The nice guys at M Tech make state of the art rovers that do video and laser profiling of underground pipes. We talked Chris Cira into demonstrating a rover in our Em2 model; he neutralized a couple of salmon poachers, along with their cabin.
And here are a couple of cool entrepreneurs, Mitzi Bender and Karen Bell, who're on a second career designing and selling some well designed rain barrels. These units have planters in the top, and they're working on a version that has a small greenhouse. You can find them here.
Friday, June 4, 2010
We've been developing an electronic device that will drive the pump in our Em2 models, replacing mechanical valves and also giving precise flow data in digital form.
The small DC pump motors are best controlled with pulse width modulation (PWM)--an electronic controller ouputs very fast (~20Hz-30KHz) on and off signals.
I picked up a vintage analog oscilloscope on Ebay to analyze the device's output. It came today and I was thrilled to hook it up.
And only after seeing that cool blue-green CRT come to life did I realize how my past has intersected with our current mission, and it's a cool story.
In 1975 I won a scholarship to attend a special electronics summer camp at the University of Arkansas Fayetteville. (My single Mom drove 18 hours straight to get me there from southern Arkansas and be back in time for work. In a Ford Pinto. Thanks, Mom.)
I'm very hands on and visual, and loved learning to use an oscilloscope--despite a scary forest of knobs, it made sense to me--it converts voltages and waveforms into visual things. You can see frequencies, amplitude of waves, their shape. Knobs control the X and Y scales; these things convert the unseeable fluxes of electrons into elegantly simple plots.
And only this afternoon did I realize how this little electronics camp has come full circle--in 1975 an outreach program at the University of Arkansas taught 15 year old me to use this instrument. After 35 years (I haven't touched an oscilloscope since then) I drew on that knowledge to develop open source tools for (we hope, with funding from NSF) wonderful science outreach programs using our models.
Photos: PWM signal on the Tektronix 425 ($230 on Ebay!); Lily poses with her new toy.
Here's a great website on oscilloscopes and their use. The oscilloscope photo shows a PWM signal, kind of messy because we don't have the correct probes for it yet; the upper line is ~12 volts, middle jagged one is zero volts. Each vertical black line is 2ms (so frequency would be 125Hz).
I won't go into the details*, but I've decided to go back to a "sawhorse" configuration for the legs. It's cheaper, very strong, and easy to build.
We're all too close to the process to have an opinion now. What do you think of the aesthetics?
Top, old sawhorse supports; middle, concept for detachable legs; and bottom, for new sawhorse supports. Do you strongly favor the look of the middle design over the bottom one?
After all this I suspect most people won't much care! Thanks for your help.
*If you're interested; our calcs for static loads on the box with the a few people leaning on it top 700 pounds. There can be tremendous side loads on the legs . This requires some very substantial attachment points on the box bottom, increasing weight and cost; in the end the horse configuration, while not as clean-looking as single legs, probably cannot be beat for weight, strength, and cost optimization