20201215 Ver 1_PreFiling Acknowledgement Email_20200925 (3)

LreeK. I ne malntalnea easement is aouttea Dy torestea areas on eltner
side. Small stream/wetland complexes are located north and south of the
stream where the exposed was identified. Mowing equipment crosses these
areas at locations where riprap has historically been placed. Riprap at the
northern crossing has become dispersed or embedded to a degree that it
is no longer effective to provide equipment support. The vicinity consists of
open land, pastures, forested areas and scattered residential
development.
To replace the segment of exposed gas line, DENC plans to install a new
section of pipe below the existing streambed at a sufficient depth to help
prevent its future exposure. The work will be conducted using industry -
standard mechanized equipment (track hoe and side -boom). Access for
construction equipment will be from Wright Road to the south. To prevent
impacts to a stream/wetland located between Wright Road and the
exposure, timber mats will be placed across an existing riprap crossing.
The mats will then be removed and the area restored upon project
completion.
The pipe replacement work will be conducted "in -the -dry" by constructing
coffer dams upstream and downstream of the exposure. A dry workspace
will then be established by pumping clean water from above the upstream
coffer dam and around the work area to below the downstream coffer dam.
The water will be pumped into a filter bag or dewatering structure sited in a
vegetated area on the west side of the work area, and the water will
eventually flow back into the stream. Secondary containment will be utilized
to prevent any leakage associated with the pump.
The new pipe will be staged on -site and fabricated as a "box -section" that
can be efficiently installed by conventional methods. The new pipe will be
placed at a depth approximately five feet below the bed of the stream in
order to maintain sufficient separation from the ground surface. Upon
installation and tie-in of the newgas line segment, the exposed gas line
segment will be removed. To inhibit the potential for future bank erosion
and instability, the streambanks within the easement, which are currently
eroded and nearly vertical, will then be graded at a 3:1 slope, seeded with
a native riparian seed mix and matted with coir fabric.
Minor permanent impacts to two wetland areas within the existing easement
are also proposed. Riprap was historically placed within portions of WA and
WB in order to accommodate passage of tractors with bush hogs and
maintenance equipment. Over time, the riprap within Wetland B has been
displaced and embedded such that vehicular passage through the area
cannot be accomplished without significant disturbance to the wetland. To
provide more reliable equipment access to this area during future
maintenance activities, the former rip -rapped crossing within the area north
of the exposure will be replaced with a new low-water crossing. The low
water crossing will be established by installing an articulated concrete block
(ACB) mattress across the stream and wetland. The mattress will be
embedded such that the stream can continue to flow through the area. The
embedded mattress will provide a firm equipment base, allowing mowing
equipment to cross the area with minimal disturbance, and the original
grade and contour of the wetland can be better maintained.
Please give a couple of dates you are available for a meeting.
9/23/2020
9/25/2020