With less than a month left until the winter weather shuts down
the ongoing rehabilitation of Marilla dam and reservoir, Nick
Cummins, a superintendent at Bob Cummins Construction Co., said his
crews are racing to lay the concrete for the new spillway.

Cummins told The Era recently “it’s gonna be close” getting the
spillway slab installed before winter. The wet weather lately has
all but completely refilled the reservoir, which was drained for
the project at the beginning of the year.

Because of the high water, construction crews have been “doing
any back-filling (they) can do,” most recently, Cummins said,
meaning they are replacing the soil between and around both the
remaining original and newly installed concrete walls.

Cummins said the task, though it is both extensive and costly,
is not an unusually complex project for the company. It is,
however, more weather dependent than most jobs, he said.

So far, construction workers have excavated the old spillway
channel, installed concrete footers and retaining walls on each
side of the spillway, and installed several thousands of feet of
gabion baskets (wire baskets filled with rock) for stability.

One slightly unusual aspect of the project, he said, is that all
the fill material used around the walls has to be clay or a
clay-like material, because it is nonporous or impermeable, Cummins
said. It compacts and seals around the retaining walls, he
added.

The fill material has been excavated from Bradford City Water
Authority watershed property across the road from Marilla on West
Washington Street.

Cummins Construction Co. has also re-lined the drain and raw
water lines that pass under the dam. Feed into the “raw water” line
eventually ends up at the water treatment plant, he said.

“One of the hardest parts of the project,” Cummins said, “has
been keeping in compliance with all the regulatory or government
agencies and meeting their mandates.”

The contractors, engineers and water authority are all at the
mercy of the state Department of Environmental Protection and
federal Bureau of Dams for each step taken as the project
unfolds.

The Bureau of Dams deemed Marilla unsafe in 2004, citing
concerns over the stability of the dam itself and the capacity of
the spillway. Engineers working for the authority drafted a plan
shortly thereafter that they felt would bring the dam and reservoir
into compliance with state and federal regulations.

That plan would have cost the authority about $2 million. After
several meetings with DEP and Bureau of Dams officials, however,
changes to the designs for rehabilitation submitted by those
governmental officials bumped the project up to $2.9 million, water
authority executive director Kim Benjamin announced this
spring.

Cummins Construction Co. was awarded the project in May with a
low bid of $2,941,210.

One of the factors taken into consideration when pricing the
project is the use of a relatively new construction material,
roller-compacted concrete or RCC. Starting in May of next year,
Cummins crews will face the challenge of installing the portion of
the new spillway made of RCC.

RCC, a nearly dry cement mix, was developed and came into its
own in the 1980s, according to a presentation given by the Bradford
City Water Authority in March of 2005, but has only recently been
used by companies locally, Cummins said.

A big factor in installing the RCC, he said, is that “once you
start the RCC, you have to keep going. It’s a continuous project
and will require a number of consecutive days with nice weather for
ideal placement.”

Cummins said the company has subcontracted an RCC specialist to
assist in the installation.

The projected completion date when the Marilla rehabilitation
was first proposed was November of 2006. Taking the recent weather
into consideration, the projected completion date is now June of
2007, Cummins said. After winter forces the end of the project for
this year, crews will likely start back on the project in March, he
said.