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.
back to the Town Diary front page