Stories from the "E" File: The Soil Test
Professional Surveyor Magazine - June 2012
The experience of growing up in the center of what is known to geologists as a “bird’s foot delta” provides a different perspective on the concept of permanence. Unlike lands that are blessed with a more or less dependable topography, the swamps and bayous of southeast Louisiana are forever changing. Perhaps it is this very lack of environmental dependability that is the impetus behind the famous Cajun joie de vivre
Fingers of distributary streams spread out to the Gulf of Mexico, depositing soil in an almost precise gradation. The banks near the stream are favored with compact clays, while the wide areas trapped in the webbing of the bird’s foot are filled with organic, unconsolidated muck. There are wide areas between the muck-filled swamp and the mounded, natural levees that have been enclosed by protective levees. These “fast lands” were initially farmed with great success and later abandoned to be converted into wooded lowlands. These areas only mimicked land.
A full understanding of the inexorable changes that are coming to this important region and the dynamics involved in those changes is only now emerging. Geographical Navigation Satellite Systems (GNSS) is the most powerful tool in analyzing, understanding and providing a dependable prognosis of the geological changes that are coming. But if I had been observant, perhaps the many clues that came my way would have hastened my understanding. One such clue occurred in 1962.
A small community had grown beside one of the distributaries of the Mississippi River. Originally a collection of truck farms providing produce to the city of New Orleans, the place known as Poydras, Louisiana, decided that it was too big and too modern to permit the continued use of outhouses and septic tanks for the disposal of residential waste. A new and modern sanitary sewerage disposal system was proposed and a tax passed to fund the project.
The crowning achievement of the project was a modern treatment pond situated far from the population center. A network of gravity sewers and pumping stations would transport waste water to an isolated tract of land far from eyes or noses that might be offended by the less-than-tidy process of open-pond sewerage treatment. Attached to that pond would be a large control building designed to regulate the outflow from the pond by the operation of flues and gates. The construction of that concrete control building provided me with an advanced warning of geological facts that I blissfully ignored.
I was working my summer job as a brush-cutter/chainman/rodman/go-for on a survey crew charged with providing grade and location for the structure. The land had been cleared of all vegetation, mostly Cypress and Tupelo gum trees. The late summer had been unseasonably dry and the hot sun had turned the bare earth into a baked clay field. The soil was black and rich. I could see why this had been such a successful truck farm, but refrigeration and mega-farms under-sold the local produce farmer.
The contractor had constructed a mile of plank road into the site from the nearest highway. While our survey crew began staking out the building site and establishing grade for the project, a huge pile driver tracked along the plank road. The wide steel tracks made loud popping sounds as the giant machine crawled along at the pace of a walking man.
With our work done, we drifted off to the side to watch. I noticed that the plank road was being crushed into the land as the machine passed and mentioned it to the survey party chief, Pap Dadar.
“I bet dey don get dat out again, me,” Pap said. “One good rain, an dey all go down.”
Pap knew about heavy machinery. “One tym, I seen a dozer sunk ‘til you could step from da lan down to da top of da cab,” he said. “Dat lan like a pie crust. Buss de crust an yo don never stop.”
The pile driver reached the location for the first pile, and the intricate process of assembling the apparatus began. Another layer of board road was added and the latticed boom trucked in separately, the three portions combined and attached to the front of the machine. Once the boom had been completed the long guide for the hammer was hauled in and lifted into place.
The last item brought in was the contractor’s pride and joy: a brand-new, $5,000 diesel hammer: the cutting edge of 20th century pile-driving technology. The truck carrying the hammer maneuvered into a position where the cables trailing down between the greased rails of the ladder could be fastened to the frame of the hammer. The ladder had been canted forward about 30 degrees to align with the guides on the side of the hammer. Cables were attached to the appropriate rings, and the signal was given for the operator to winch in the lines.
Once the weight of the hammer was taken up by the cables, the truck was driven away and a swarm of men inspected the connections. Satisfied that all was in order, the ground guide signaled for the operator to pull the hammer to the top of the ladder where fuel lines and other connections could be made. We all watched as the machine drew the steel-encased piston up 60 feet to the crown.
“It must weigh ten tons,” I said.
“If dat so,” Pap said. “It’s a little one. T’marteau
When the hammer reached the crown of the derrick, a grinding screech came from the cable spool and something flew into the sky from the top of the hammer. It was the frayed and free end of the haul line. The clamps holding the cable had slipped off, freeing the hammer.
Down she came! Slowly at first, but then gaining speed with every inch of free fall, the hammer blurred until it was an elongated red streak when it reached the ground. Broken splinters of planking and mud flew everywhere as if a land mine had exploded. We had to have been 200 feet from the entry point, yet we were showered with clods of black dirt and debris.
Stunned, I wiped the mess from my clothes and noticed some of the dirt was wet.
“Poo-ya!” Pap said. “I tink dey buss dat crust for true now, me!”
The empty ladder pointed toward a great crater that was beginning to fill with water. Men were running back and forth, shouting and gesturing. Finally, after it had been determined that no one was injured, a mob collected around the crater. Proposals on how the hammer could be recovered began to pour from all sides.
“How do you think they are going to get the hammer?” I asked. The crater was a smooth pool of putrid water. Men were poking long poles into the inky surface, feeling for the steel cylinder.
“I tink we go to Teta’s” Pap said. “I bet we don see dat hammer no more, me.”
Pap logged out the field book, and our survey crew ended the day at Teta’s sipping cold beer and recounting the day’s adventure with an unbelieving bartender.
And the hammer? It’s still there, somewhere under an obsolete and abandoned treatment pond.
Stephen Estopinal, PE, PLS is assistant division manager and senior project manager at SJB Group, LLC in Louisiana. He has been involved in the practice of land surveying for more than 30 years and is the author of “A Guide to Understanding Land Surveys 3rd ed.” John Wiley & Sons, Inc. 2009.
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