Town Diary - August 2002
River crossing of the gas pipeline in Riverton.
During late July and early August, motorists going between Pleasant Valley and Riverton have witnessed some unusual construction activity on the Farmington River just below Riverton. Workers there have completed a major improvement to the natural gas pipeline running under the Farmington River. The work was finished in just over 2 weeks with minimal delays to traffic. Fisherman, tubers and kayakers continued to enjoy the Farmington River during the construction because the river flow was only partially blocked during construction.
Photo- The new eight inch pipe used to upgrade an 850 foot section of the pipeline.
Photo- Installing sections of pipe on the east side of the Farmington River below Riverton. The two workers way in back at the far right are standing on East River Road near the river.
The purpose of the project was to replace an 850-foot section of pipeline, upgrading the existing six-inch pipe to an eight-inch pipe. In 1992 the entire pipeline had been replaced with eight-inch pipes except for this one section. The 850 foot section runs under East River Road, West River Road and the Farmington River. This section was not upgraded in 1992 because at the time the owner of the pipeline, Tennessee Gas Pipeline, did not have the required permits to cross the river with the eight-inch pipe. The two different pipes sizes were connected and the pipeline still carried natural gas during this period but the choke point did not allow ongoing testing of the pipeline. Federal Department of Transportation regulations call for pipelines to be electronically tested for safety purposes with a device that travels through the line. These devices, nicknamed "pigs" cannot be used on a line that changes diameter such as was the case under the Farmington River.
Photo- New pipe (on the right) meets old pipe. Workers would later splice the two lines together at this point on the east side of the river crossing.
With the upgrade to the eight-inch pipe, the chokepoint has been eliminated and the pig can travel the entire distance of the pipeline. The entire line is called the "Torrington Lateral" and is a branch off the main gas line in Massachusetts. The Torrington Lateral runs southwest and terminates in Torrington, supplying natural gas to customers in Winsted and Torrington. Tennessee Gas Pipeline is a subsidiary of El Paso Energy, which brings natural gas into our area from sources around the Gulf of Mexico and also now from Canada. The Torrington Lateral was originally constructed in 1947.
Photo- Excavator inside the coffer dam on the east side of the Farmington River. The iron plates partially showing at the bottom right of the photo allow traffic on East River Road to cross over the pipeline trench. The worker on the left is standing in front of two large pumps which are removing water that has entered the coffer dam.
Photo- a view from the west side of the river looking to the northeast. Note the red car, which is on East River Road, crossing iron plates on the road over the pipeline trench.
The pipeline upgrade work under the Farmington River is being done by a contractor, Delta Gulf Corporation out of Louisiana, although about half the work crew on the project are from this area. After securing the required permits the construction started in late July. The process involves constructing a coffer dam around a portion of the river crossing, allowing heavy equipment access to the river bed. Any water leaking into this area is pumped out. The old pipe is exposed and removed and the new eight-inch pipe installed. The pipeline is buried to a depth of about 5 feet. The coffer dam is then dismantled and re-constructed on the opposite side of the river and the process repeated. The new pipe is also run under East River Road and West River Road. Large steel plates are placed on the road over the trench to allow cars to pass, keeping traffic delays to a minimum.
Photo- Installing pipe on the west side of the river.
In addition to the work in Riverton, "launchers" and "receivers" will be installed at each end of the Torrington Lateral. These devices facilitate use of the pig, which periodically travels the length of the pipeline, electronically testing the integrity of the pipe.
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