Thursday, May 28, 2009

NSF MRI-R² webcast.

NSF hosted a webcast todayon the special MRI-R² solicitation. I've updated a past post with other information and a link to the archived webcast.

And here's something funny via Clastic Detritus.

Tuesday, May 26, 2009

Dunes and a beautiful delta in Lake Eyre.


Like some other bloggers I know, I can't resist pointing to yet another image from NASA's Earth Observatory site. This one if of Australia's Lake Eyre basin.

Just go read the description there. In how many places do we see a delta system and sand dunes cutting through one other?

And an amazing ecosystem to boot--see the Australian Broadcasting Corp. video (referenced by the EO site) here.

Saturday, May 23, 2009

A wonderful book on water lifting devices.


Water Lifting Devices, by P.L. Fraenkel and Jeremy Thake.

My wife Kate loves libraries, and on one of our recent trips to the newly remodeled Morris Library at SIUC, I happened to spot this book. I've done innumerable internet searches on pumps and related technology for our river model development, but had never seen this one. Score another one for books on shelves.

The book's aim is a review of applied pumping theory and practice, and description of pumps suitable for, mostly, third world applications. It's amazingly comprehensive, with wonderful sections on theory and pump efficiency--even covering generation of electricity using wind, hydro, and biogas.

Pumping is a difficult topic. This book does an admirable job of making it accessible.

If you work with pumps or fluid mechanics, or are interested in mechanical devices (and their history) you'll enjoy this book. Many of the technologies described, such as the Archimedes Screw, are centuries old and most rely on human or animal power.

You can find the most recent version (3rd edition, 2007) on Amazon.com here, and it seems the UN-FAO has an older online version with a linked table of contents here. Both are richly illustrated.

I also found a wonderful collection of photographs covering this topic by Thorkild Schi├Âler here. A photo from this site, of a Chinese "dragons's spine" pump powered by three treaders, is shown below.

Tuesday, May 12, 2009

An "inland hurricane" hits Carbondale.


Last Friday, as a massive storm system we now know was a meso cyclone, roared through southern Missouri and Illinois. Soon after lunch we sheltered in our safe spot at LRRD as sustained winds of 80 mph hit. It's being called and "inland hurricane," and that's an apt description because the damage is very similar. Nearly every block in Carbondale was at least partly blocked as trees came down, often taking overhead utilities with them. News articles here, gif animation here, and here. Not much on the national news, though the damage from this will likely approach that of a major hurricane hitting the Gulf coast.

In Illinois, the damage covers several counties, and we're told Carbondale took the brunt of it. Hardly a home stands undamaged. I counted over 30 trees destroyed on the 3-acre lot my in-laws own.

A 36-inch red oak came down on the back of our building, giving us quite a shock. Like many huge old oaks that were destroyed, it was simply uprooted. Constant rain over the last two weeks left soils saturated, and many healthy trees were destroyed this way. Bad luck.

We just regained power the Internet connection today, though many of us will be without power for several days at home.

Top image is the NOAA Radar, which I captured an hour or so before the winds hit us.

Update: Radar imagery from the University of Wisconsin. A week after the storm, many thousands of homes (including mine) are still without power, and Carbondale estimates over 3,000 trees came down in the City.

Thursday, May 7, 2009

Watts Branch, Walter and Merrits


From Earthmagazine.org, a nice piece on last year's controversial Science article by Walter and Merritts (links here)and its implications for restoration, with commentary from Peter Wilcock and Frank Pazzaglia.

Until now I wasn't familiar with Pazzaglia's work, but it looks very interesting.

I had strong feelings about the Walter and Merritts paper--I remember well, as a young river scientist working for the Missouri Department of Conservation, first seeing photos of Watts Branch, the model Leopold and others held up as a typical meandering stream. It didn't look right to me, incised and stripped of woody vegetation--probably grazed by cattle. I never thought it was a good study subject, certainly not to describe a typical unimpacted channel segment.

Here's the photo of Watts Branch, from Fluvial Processes in Geomorphology.

Wednesday, May 6, 2009

Grade control Part 1.



I've been working on an incised urban channel needing grade control, and took the opportunity to review what's out there, and also my own thick files. Here I'll talk a bit about theory, practice, and the politics of using grade control in channel management.

First, a skydiver. On leaving the plane he has huge potential energy relative to the ground thousands of feet below. After opening his chute, he slowly dissipates that energy by converting it to kinetic energy using a parachute.

Water works the same way. Especially in urban channels, I use this simple conceptual approach: We have a certain volume of water entering our area of interest at a certain elevation. As this flow moves down the channel, potential energy (from the elevation difference) is converted to kinetic energy and dissipated. How that conversion and dissipation happens largely controls channel erosion and sediment transport.

Grade control structures are a way to manage this. At the top of this figure we see a smooth channel. Conversion of potential (PE) to kinetic energy (KE) is more or less evenly distributed throughout the reach. Below we've added grade controls. What's important here is that we now see 1) most of the energy is now dissipated only at discreet locations (the GC structures) and 2) we pick and armor those locations.

Pretty simple. And it works. In theory, you don't have to armor the channel between these structures. One of the many things about river mechanics that is counterintuitive to most people.

Friday, May 1, 2009

Em2 models on a map.


View Emriver Em2 models in a larger map

We've been busy shipping Em2 models this month--it seems the economy is recovering, or at least agency budgets are moving past last fall's severe cuts.

So we took some time to map the locations of our Em2 models. It's a nice feeling to see the impact we're having. Some of the locations have several models; Winona State has six Em2's (and an Em4).