Saturday, January 26, 2013

Gorgeous View, Haphazard Town: Porto Empedocle, Sicily

Porto Empedocle is a seaport in southern Sicily. Most tourists in the area do not bother with the Port because their destination is the famous Valle dei Templi (Valley of the Temples or in Sicilian: Vaddi di li Tempri), an astonishing ancient Greek archaeological site in nearby Agrigento. On a recent road trip around Sicily, the coast highway E931 took me right through Porto Empedocle, and it looked too interesting to not stop.
The town is the terminus for ferry boats that go to the islands of Linosa and Lampedusa. Lampedusa, only 110 km from the coast of Tunisia, was in the news in 2011 because thousands of escapees from Libya and Tunisia were quarantined there in refugee camps. Remote Linosa was once a penal colony for Mafia chieftains and thugs. In the 1930s, dictator Benito Mussolini almost succeeded in eradicating the Mafia by executing hundreds (thousands) and banishing hundreds to prison camps on Linosa. But the American forces in 1943 enlisted the Mafia to help overthrow the Germans, put the Mafia back in power in rural towns all over Sicily, and the rest is history (Duncan, P. 1994. Sicily: A Traveller's Guide, John Murray Publishers Ltd.).
The town is built on two levels. The port and lower town are on the coastal plain, while the upper town is about 100 m higher on a limestone ridge. The lower town is a warren of twisty lanes with haphazard multi-floor apartments. Some may be late 1800s-vintage, but most look like dumpy post-World War II units, with an occasional modern monstrosity. The photographs above were taken from the Via Mare road that runs along the ridge.
Up on the ridge, all of the apartment blocks look to be post-1960s. The town has been known for its sulfur mines since antiquity. Do all these people work at the sulfur factory?
We saw some children playing, but the streets were pretty quiet mid-day on a Saturday. A supermarket tucked into the basement of one of these apartments was busy.
The streets reminded me of people's housing blocks I saw in the old Soviet Union, except here there were more private cars and the general maintenance condition was better.

Do not let me discourage you: Sicily is a spectacular tourist destination, and the people are very friendly.  The history spans the Phoenicians, Carthaginians, Greeks, Romans, Moors, and Normans.

Photographs taken with a Panasonic G1 digital camera. These look different then my previous Panasonic images because I processed the raw files with Photo Ninja. This is an amazing software that extracts subtle details from the files - highly recommended!

Saturday, January 12, 2013

Mississippi Basin Model construction and instruments

Regular readers may remember my earlier posts about the Mississippi Basin Model from early 2010, July 2010, and Dec. 2010. This was the most comprehensive hydraulic model ever built, meaning it covered the largest land extent of any model. The Corps of Engineers also built a Chesapeake Bay Model and one of San Francisco Bay. The Chesapeake model only had a full operational life of three years and is now gone.  But the San Francisco model still exists and is open to visitors in a warehouse in Sausalito.

Building a model like this is a complex project requiring precise scaling and ultra-precise shaping of the terrain. I found some photographs that help explain how a scale physical hydraulic model like this is constructed.
In the first photograph, metal templates that show the topography have been laid out across the soil at specified intervals. The templates usually have vertical exaggeration, such as 1:10, meaning vertical distance is scaled 10 times greater than the horizontal scale. Then the soil is moved and shaped to approximately match the templates.

At the Mississippi Basin Model, the original earth work, excavating canals, and installing piping was performed by German prisoners of war.  The Germans were repatriated in 1946, and the remaining model construction was done by civilian employees.  The template method of shaping the terrain was used between 1946 and approximately 1953.  But the expansive soil in the area required a shift to the contour method of construction (not shown in these photographs).
In the second photograph, the workers are carefully pouring concrete and shaping the surface to exactly match the top of the templates. This is painstaking work requiring years of experience. The labor, time, and space requirements underscore why building physical models is so expensive.
This is an electronic water-level follower, meaning an instrument to measure water level. Notice that electronic circuits means vacuum tubes!
Finally, here is one of the Stevens chart recorders that plots the water level over time. As the paper drum turns, an ink pens moves up and down on the guide rails.
This is a January, 2010, photograph of one of the controls rooms at the Basin Model. Since then, all the Stevens recorders have been removed, probably stolen.

Historical black and white photographs courtesy of the Coastal and Hydraulics Laboratory, Engineer Research and Development Center, US Army Corps of Engineers.