Erosion Control March/April 2017 : Page 26

LADIE DURKIN Edmonton, AB, Canada. Pipeline was installed The new pipeline is 22 across the Niangua River. inches in diameter. “We integrated a smart tool throughout the pipe-line. It has magnets that tell the thickness of the pipe,” explains Durkin. If corrosion thins a spot of the new pipeline, GPS can locate it precisely. Then only that section of pipe will have to be uncovered and spot-welded, saving both time and expense. In addition to replac-ing the worn out 22-inch diameter pipeline, the project cut back and removed an even older 10-inch-diameter pipe-line for 50 feet on either side of the river for safety reasons. It had been laid shallowly enough that kayaks some-Cofferdams were essential for times got caught on it. “You could see providing dry work area for removing the marks where the kayaks had hit it,” the old pipelines and installing the new says Durkin. one. Minnesota Limited relied on cof-ferdams from Dam-It Dams of Grand Blanc, MI. “We put a Dam-It Dam upstream and another one downstream to divert the river,” says Durkin. The upstream dam was 250 feet long, 8 feet tall, and 24 feet wide. The downstream dam measured 225 feet long, 6 feet tall, and 18 feet wide. The dams were about 300 feet apart. Pumping the river water into them and doing the rest of the installation took only a couple of days. Removal went more quickly. Depth of the Niangua River was generally about 6 feet at the project site, but that varied. During heavy rain it increased to as much as 15 feet. Durkin says that a drop of 2 feet from one side to the other led to a stronger cur-rent on one side. The terrain surround-ing the river was rough. “On the upstream side, we put sand bags through the river, to start with, so the dam wouldn’t be washed away. There were lots of tree branches and debris floating through,” he adds. Weather was a major hassle on this job. Besides the typical heat and humidity of a Missouri summer, there were some big rainstorms with subse-quent severe flooding. Durkin says that after one storm, “We couldn’t install anything. We waited for 10 days for the site to dry out. Another time work was postponed for a month.” Deer and wild turkeys posed no problems, running away when they saw the workers. Some very small fish, however, caused a big problem, delaying work. The Niangua Darter measures only about 4 inches when fully grown. It is one of more than 30 species of perch-like darters found in Missouri rivers and lakes. Because the species is listed as endangered by the Missouri Department of Conservation, and as threatened by federal authorities, care had to be taken to see that no fish were harmed. Durkin says that, unfortunately, “Some of these darters got trapped inside a cofferdam. We had to pump the water out. Biologists from the WWW.EROSIONCONTROL.COM 26 EROSION CONTROL

King Hughes

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